Abseil Common Libraries (C++) (grcp 依赖) https://abseil.io/
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// Copyright 2018 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// MOTIVATION AND TUTORIAL
//
// If you want to put in a single heap allocation N doubles followed by M ints,
// it's easy if N and M are known at compile time.
//
// struct S {
// double a[N];
// int b[M];
// };
//
// S* p = new S;
//
// But what if N and M are known only in run time? Class template Layout to the
// rescue! It's a portable generalization of the technique known as struct hack.
//
// // This object will tell us everything we need to know about the memory
// // layout of double[N] followed by int[M]. It's structurally identical to
// // size_t[2] that stores N and M. It's very cheap to create.
// const Layout<double, int> layout(N, M);
//
// // Allocate enough memory for both arrays. `AllocSize()` tells us how much
// // memory is needed. We are free to use any allocation function we want as
// // long as it returns aligned memory.
// std::unique_ptr<unsigned char[]> p(new unsigned char[layout.AllocSize()]);
//
// // Obtain the pointer to the array of doubles.
// // Equivalent to `reinterpret_cast<double*>(p.get())`.
// //
// // We could have written layout.Pointer<0>(p) instead. If all the types are
// // unique you can use either form, but if some types are repeated you must
// // use the index form.
// double* a = layout.Pointer<double>(p.get());
//
// // Obtain the pointer to the array of ints.
// // Equivalent to `reinterpret_cast<int*>(p.get() + N * 8)`.
// int* b = layout.Pointer<int>(p);
//
// If we are unable to specify sizes of all fields, we can pass as many sizes as
// we can to `Partial()`. In return, it'll allow us to access the fields whose
// locations and sizes can be computed from the provided information.
// `Partial()` comes in handy when the array sizes are embedded into the
// allocation.
//
// // size_t[1] containing N, size_t[1] containing M, double[N], int[M].
// using L = Layout<size_t, size_t, double, int>;
//
// unsigned char* Allocate(size_t n, size_t m) {
// const L layout(1, 1, n, m);
// unsigned char* p = new unsigned char[layout.AllocSize()];
// *layout.Pointer<0>(p) = n;
// *layout.Pointer<1>(p) = m;
// return p;
// }
//
// void Use(unsigned char* p) {
// // First, extract N and M.
// // Specify that the first array has only one element. Using `prefix` we
// // can access the first two arrays but not more.
// constexpr auto prefix = L::Partial(1);
// size_t n = *prefix.Pointer<0>(p);
// size_t m = *prefix.Pointer<1>(p);
//
// // Now we can get pointers to the payload.
// const L layout(1, 1, n, m);
// double* a = layout.Pointer<double>(p);
// int* b = layout.Pointer<int>(p);
// }
//
// The layout we used above combines fixed-size with dynamically-sized fields.
// This is quite common. Layout is optimized for this use case and generates
// optimal code. All computations that can be performed at compile time are
// indeed performed at compile time.
//
// Efficiency tip: The order of fields matters. In `Layout<T1, ..., TN>` try to
// ensure that `alignof(T1) >= ... >= alignof(TN)`. This way you'll have no
// padding in between arrays.
//
// You can manually override the alignment of an array by wrapping the type in
// `Aligned<T, N>`. `Layout<..., Aligned<T, N>, ...>` has exactly the same API
// and behavior as `Layout<..., T, ...>` except that the first element of the
// array of `T` is aligned to `N` (the rest of the elements follow without
// padding). `N` cannot be less than `alignof(T)`.
//
// `AllocSize()` and `Pointer()` are the most basic methods for dealing with
// memory layouts. Check out the reference or code below to discover more.
//
// EXAMPLE
//
// // Immutable move-only string with sizeof equal to sizeof(void*). The
// // string size and the characters are kept in the same heap allocation.
// class CompactString {
// public:
// CompactString(const char* s = "") {
// const size_t size = strlen(s);
// // size_t[1] followed by char[size + 1].
// const L layout(1, size + 1);
// p_.reset(new unsigned char[layout.AllocSize()]);
// // If running under ASAN, mark the padding bytes, if any, to catch
// // memory errors.
// layout.PoisonPadding(p_.get());
// // Store the size in the allocation.
// *layout.Pointer<size_t>(p_.get()) = size;
// // Store the characters in the allocation.
// memcpy(layout.Pointer<char>(p_.get()), s, size + 1);
// }
//
// size_t size() const {
// // Equivalent to reinterpret_cast<size_t&>(*p).
// return *L::Partial().Pointer<size_t>(p_.get());
// }
//
// const char* c_str() const {
// // Equivalent to reinterpret_cast<char*>(p.get() + sizeof(size_t)).
// // The argument in Partial(1) specifies that we have size_t[1] in front
// // of the characters.
// return L::Partial(1).Pointer<char>(p_.get());
// }
//
// private:
// // Our heap allocation contains a size_t followed by an array of chars.
// using L = Layout<size_t, char>;
// std::unique_ptr<unsigned char[]> p_;
// };
//
// int main() {
// CompactString s = "hello";
// assert(s.size() == 5);
// assert(strcmp(s.c_str(), "hello") == 0);
// }
//
// DOCUMENTATION
//
// The interface exported by this file consists of:
// - class `Layout<>` and its public members.
// - The public members of class `internal_layout::LayoutImpl<>`. That class
// isn't intended to be used directly, and its name and template parameter
// list are internal implementation details, but the class itself provides
// most of the functionality in this file. See comments on its members for
// detailed documentation.
//
// `Layout<T1,... Tn>::Partial(count1,..., countm)` (where `m` <= `n`) returns a
// `LayoutImpl<>` object. `Layout<T1,..., Tn> layout(count1,..., countn)`
// creates a `Layout` object, which exposes the same functionality by inheriting
// from `LayoutImpl<>`.
#ifndef ABSL_CONTAINER_INTERNAL_LAYOUT_H_
#define ABSL_CONTAINER_INTERNAL_LAYOUT_H_
#include <assert.h>
#include <stddef.h>
#include <stdint.h>
#include <ostream>
#include <string>
#include <tuple>
#include <type_traits>
#include <typeinfo>
#include <utility>
#ifdef ADDRESS_SANITIZER
#include <sanitizer/asan_interface.h>
#endif
#include "absl/meta/type_traits.h"
#include "absl/strings/str_cat.h"
#include "absl/types/span.h"
#include "absl/utility/utility.h"
#if defined(__GXX_RTTI)
#define ABSL_INTERNAL_HAS_CXA_DEMANGLE
#endif
#ifdef ABSL_INTERNAL_HAS_CXA_DEMANGLE
#include <cxxabi.h>
#endif
namespace absl {
Export of internal Abseil changes -- c99f979ad34f155fbeeea69b88bdc7458d89a21c by Derek Mauro <dmauro@google.com>: Remove a floating point division by zero test. This isn't testing behavior related to the library, and MSVC warns about it in opt mode. PiperOrigin-RevId: 285220804 -- 68b015491f0dbf1ab547994673281abd1f34cd4b by Gennadiy Rozental <rogeeff@google.com>: This CL introduces following changes to the class FlagImpl: * We eliminate the CommandLineFlagLocks struct. Instead callback guard and callback function are combined into a single CallbackData struct, while primary data lock is stored separately. * CallbackData member of class FlagImpl is initially set to be nullptr and is only allocated and initialized when a flag's callback is being set. For most flags we do not pay for the extra space and extra absl::Mutex now. * Primary data guard is stored in data_guard_ data member. This is a properly aligned character buffer of necessary size. During initialization of the flag we construct absl::Mutex in this space using placement new call. * We now avoid extra value copy after successful attempt to parse value out of string. Instead we swap flag's current value with tentative value we just produced. PiperOrigin-RevId: 285132636 -- ed45d118fb818969eb13094cf7827c885dfc562c by Tom Manshreck <shreck@google.com>: Change null-term* (and nul-term*) to NUL-term* in comments PiperOrigin-RevId: 285036610 -- 729619017944db895ce8d6d29c1995aa2e5628a5 by Derek Mauro <dmauro@google.com>: Use the Posix implementation of thread identity on MinGW. Some versions of MinGW suffer from thread_local bugs. PiperOrigin-RevId: 285022920 -- 39a25493503c76885bc3254c28f66a251c5b5bb0 by Greg Falcon <gfalcon@google.com>: Implementation detail change. Add further ABSL_NAMESPACE_BEGIN and _END annotation macros to files in Abseil. PiperOrigin-RevId: 285012012 GitOrigin-RevId: c99f979ad34f155fbeeea69b88bdc7458d89a21c Change-Id: I4c85d3704e45d11a9ac50d562f39640a6adbedc1
5 years ago
ABSL_NAMESPACE_BEGIN
namespace container_internal {
// A type wrapper that instructs `Layout` to use the specific alignment for the
// array. `Layout<..., Aligned<T, N>, ...>` has exactly the same API
// and behavior as `Layout<..., T, ...>` except that the first element of the
// array of `T` is aligned to `N` (the rest of the elements follow without
// padding).
//
// Requires: `N >= alignof(T)` and `N` is a power of 2.
template <class T, size_t N>
struct Aligned;
namespace internal_layout {
template <class T>
struct NotAligned {};
template <class T, size_t N>
struct NotAligned<const Aligned<T, N>> {
static_assert(sizeof(T) == 0, "Aligned<T, N> cannot be const-qualified");
};
template <size_t>
using IntToSize = size_t;
template <class>
using TypeToSize = size_t;
template <class T>
struct Type : NotAligned<T> {
using type = T;
};
template <class T, size_t N>
struct Type<Aligned<T, N>> {
using type = T;
};
template <class T>
struct SizeOf : NotAligned<T>, std::integral_constant<size_t, sizeof(T)> {};
template <class T, size_t N>
struct SizeOf<Aligned<T, N>> : std::integral_constant<size_t, sizeof(T)> {};
Export of internal Abseil changes. -- 15d7bcf28220750db46930f4d8c090b54e3ae5fe by Jon Cohen <cohenjon@google.com>: Fix miscellaneous CMake change interleaving issues for the daily release: * add back the absl::container target * Add copts to absl_cc_library targets in absl/container/CMakeLists.txt * Add trailing newline to the end of AbseilConfigureCopts.cmake PiperOrigin-RevId: 223057096 -- baac35470d75b6561477f688dc4eb021f604cf71 by Abseil Team <absl-team@google.com>: Internal Cleanup. PiperOrigin-RevId: 223051579 -- 6791c2f2e35b030b5579f36d3c607c6ba92fa089 by Abseil Team <absl-team@google.com>: Internal Change. PiperOrigin-RevId: 223046855 -- 5467ad987ea82aef77d2f1cc85aa9105e7d9c320 by Samuel Benzaquen <sbenza@google.com>: Workaround for gcc bug https://gcc.gnu.org/PR88115 PiperOrigin-RevId: 223041901 -- 36fa5cfd41df2b71d26487c45363901bbf6a2463 by Tom Manshreck <shreck@google.com>: Clarify visit() constraints PiperOrigin-RevId: 223032194 -- afdf4013de036b411db7f92cde8a2493e6665223 by Abseil Team <absl-team@google.com>: Fix comment typos. PiperOrigin-RevId: 223024090 -- e11c01927eb8b898f6633282824022104b258342 by Jon Cohen <cohenjon@google.com>: Make absl::spinlock_test_common TESTONLY This should fix https://github.com/abseil/abseil-cpp/issues/221 PiperOrigin-RevId: 222885323 -- 5ccc576d1c68e4b92705aa8064f1e8d715e5415e by Abseil Team <absl-team@google.com>: Internal change. PiperOrigin-RevId: 222877017 -- 96ff25bf78c4f4bca0d6e61faa4feeab91a2e73c by Jon Cohen <cohenjon@google.com>: Align CMake and Bazel compile options. This is the first step towards a single source of truth for Abseil compile options. Also makes absl_test and absl_cc_test make binaries and targets with compatible names to each other to make testing easier. PiperOrigin-RevId: 222858408 -- 7dd3e2618ad5a5de5d918fc73e438ef0b98cec6a by Abseil Team <absl-team@google.com>: Revert "absl: cap SpinLock backoff to 4ms" PiperOrigin-RevId: 222656230 -- 0d49538a3cab714156ed0a5651656c0aa098a1e5 by Abseil Team <absl-team@google.com>: Update absl/container/CMakeLists.txt to use new functions i.e. absl_cc_(library|test) PiperOrigin-RevId: 222535766 -- 92744e9d0e5c3bf9e1167a7bdf1a6777192531b1 by Abseil Team <absl-team@google.com>: Disable header parsing for broken targets PiperOrigin-RevId: 222257218 -- 39a6c623601c44e02d91e412f126a813d719507b by Abseil Team <absl-team@google.com>: absl: cap SpinLock backoff to 4ms The current backoff logic has 3 problems: 1. It can produce too high values (up to 256ms), which can negatively affect tail latency. The value was chosen long time ago and now it's a good idea to reconsider it. 2. It does not have low bound, so on any iteration it can produce a very small value that will lead to unnecessary cpu consumption. 3. It does not increase low bound with the number of iterations. So if the SpinLock is actually somehow locked for a very prolonged time, a waiter can still wake periodically. Rework the logic to solve these problems. Add lower bound of 128us, no code should rely on absence of episodic delays in this range as they can occur everywhere. Lower upper bound to 4ms. A thread sleeping for 4ms does not consume significant cpu time (see below). Grow lower bound with the number of iterations. This is cpu consumption of a process doing usleep(x) in a loop (sampled with ps): 64us -> 4.0% 128us -> 2.7% 256us -> 3.5% 512us -> 2.8% 1024us -> 1.6% 2048us -> 0.6% 4096us -> 0.3% 8192us -> 0.0% Few millisecond sleeps do not consume significant time. PiperOrigin-RevId: 222196086 -- 17104a2396ddda61fb0faed0a72ff8c161ca17ea by Shahriar Rouf <nafi@google.com>: Add benchmarks for hashing civil_times. PiperOrigin-RevId: 222152108 GitOrigin-RevId: 15d7bcf28220750db46930f4d8c090b54e3ae5fe Change-Id: I73b929feaf6ce72b70fdafd6108f53bbbeaf9738
6 years ago
// Note: workaround for https://gcc.gnu.org/PR88115
template <class T>
Export of internal Abseil changes. -- 15d7bcf28220750db46930f4d8c090b54e3ae5fe by Jon Cohen <cohenjon@google.com>: Fix miscellaneous CMake change interleaving issues for the daily release: * add back the absl::container target * Add copts to absl_cc_library targets in absl/container/CMakeLists.txt * Add trailing newline to the end of AbseilConfigureCopts.cmake PiperOrigin-RevId: 223057096 -- baac35470d75b6561477f688dc4eb021f604cf71 by Abseil Team <absl-team@google.com>: Internal Cleanup. PiperOrigin-RevId: 223051579 -- 6791c2f2e35b030b5579f36d3c607c6ba92fa089 by Abseil Team <absl-team@google.com>: Internal Change. PiperOrigin-RevId: 223046855 -- 5467ad987ea82aef77d2f1cc85aa9105e7d9c320 by Samuel Benzaquen <sbenza@google.com>: Workaround for gcc bug https://gcc.gnu.org/PR88115 PiperOrigin-RevId: 223041901 -- 36fa5cfd41df2b71d26487c45363901bbf6a2463 by Tom Manshreck <shreck@google.com>: Clarify visit() constraints PiperOrigin-RevId: 223032194 -- afdf4013de036b411db7f92cde8a2493e6665223 by Abseil Team <absl-team@google.com>: Fix comment typos. PiperOrigin-RevId: 223024090 -- e11c01927eb8b898f6633282824022104b258342 by Jon Cohen <cohenjon@google.com>: Make absl::spinlock_test_common TESTONLY This should fix https://github.com/abseil/abseil-cpp/issues/221 PiperOrigin-RevId: 222885323 -- 5ccc576d1c68e4b92705aa8064f1e8d715e5415e by Abseil Team <absl-team@google.com>: Internal change. PiperOrigin-RevId: 222877017 -- 96ff25bf78c4f4bca0d6e61faa4feeab91a2e73c by Jon Cohen <cohenjon@google.com>: Align CMake and Bazel compile options. This is the first step towards a single source of truth for Abseil compile options. Also makes absl_test and absl_cc_test make binaries and targets with compatible names to each other to make testing easier. PiperOrigin-RevId: 222858408 -- 7dd3e2618ad5a5de5d918fc73e438ef0b98cec6a by Abseil Team <absl-team@google.com>: Revert "absl: cap SpinLock backoff to 4ms" PiperOrigin-RevId: 222656230 -- 0d49538a3cab714156ed0a5651656c0aa098a1e5 by Abseil Team <absl-team@google.com>: Update absl/container/CMakeLists.txt to use new functions i.e. absl_cc_(library|test) PiperOrigin-RevId: 222535766 -- 92744e9d0e5c3bf9e1167a7bdf1a6777192531b1 by Abseil Team <absl-team@google.com>: Disable header parsing for broken targets PiperOrigin-RevId: 222257218 -- 39a6c623601c44e02d91e412f126a813d719507b by Abseil Team <absl-team@google.com>: absl: cap SpinLock backoff to 4ms The current backoff logic has 3 problems: 1. It can produce too high values (up to 256ms), which can negatively affect tail latency. The value was chosen long time ago and now it's a good idea to reconsider it. 2. It does not have low bound, so on any iteration it can produce a very small value that will lead to unnecessary cpu consumption. 3. It does not increase low bound with the number of iterations. So if the SpinLock is actually somehow locked for a very prolonged time, a waiter can still wake periodically. Rework the logic to solve these problems. Add lower bound of 128us, no code should rely on absence of episodic delays in this range as they can occur everywhere. Lower upper bound to 4ms. A thread sleeping for 4ms does not consume significant cpu time (see below). Grow lower bound with the number of iterations. This is cpu consumption of a process doing usleep(x) in a loop (sampled with ps): 64us -> 4.0% 128us -> 2.7% 256us -> 3.5% 512us -> 2.8% 1024us -> 1.6% 2048us -> 0.6% 4096us -> 0.3% 8192us -> 0.0% Few millisecond sleeps do not consume significant time. PiperOrigin-RevId: 222196086 -- 17104a2396ddda61fb0faed0a72ff8c161ca17ea by Shahriar Rouf <nafi@google.com>: Add benchmarks for hashing civil_times. PiperOrigin-RevId: 222152108 GitOrigin-RevId: 15d7bcf28220750db46930f4d8c090b54e3ae5fe Change-Id: I73b929feaf6ce72b70fdafd6108f53bbbeaf9738
6 years ago
struct AlignOf : NotAligned<T> {
static constexpr size_t value = alignof(T);
};
template <class T, size_t N>
Export of internal Abseil changes. -- 15d7bcf28220750db46930f4d8c090b54e3ae5fe by Jon Cohen <cohenjon@google.com>: Fix miscellaneous CMake change interleaving issues for the daily release: * add back the absl::container target * Add copts to absl_cc_library targets in absl/container/CMakeLists.txt * Add trailing newline to the end of AbseilConfigureCopts.cmake PiperOrigin-RevId: 223057096 -- baac35470d75b6561477f688dc4eb021f604cf71 by Abseil Team <absl-team@google.com>: Internal Cleanup. PiperOrigin-RevId: 223051579 -- 6791c2f2e35b030b5579f36d3c607c6ba92fa089 by Abseil Team <absl-team@google.com>: Internal Change. PiperOrigin-RevId: 223046855 -- 5467ad987ea82aef77d2f1cc85aa9105e7d9c320 by Samuel Benzaquen <sbenza@google.com>: Workaround for gcc bug https://gcc.gnu.org/PR88115 PiperOrigin-RevId: 223041901 -- 36fa5cfd41df2b71d26487c45363901bbf6a2463 by Tom Manshreck <shreck@google.com>: Clarify visit() constraints PiperOrigin-RevId: 223032194 -- afdf4013de036b411db7f92cde8a2493e6665223 by Abseil Team <absl-team@google.com>: Fix comment typos. PiperOrigin-RevId: 223024090 -- e11c01927eb8b898f6633282824022104b258342 by Jon Cohen <cohenjon@google.com>: Make absl::spinlock_test_common TESTONLY This should fix https://github.com/abseil/abseil-cpp/issues/221 PiperOrigin-RevId: 222885323 -- 5ccc576d1c68e4b92705aa8064f1e8d715e5415e by Abseil Team <absl-team@google.com>: Internal change. PiperOrigin-RevId: 222877017 -- 96ff25bf78c4f4bca0d6e61faa4feeab91a2e73c by Jon Cohen <cohenjon@google.com>: Align CMake and Bazel compile options. This is the first step towards a single source of truth for Abseil compile options. Also makes absl_test and absl_cc_test make binaries and targets with compatible names to each other to make testing easier. PiperOrigin-RevId: 222858408 -- 7dd3e2618ad5a5de5d918fc73e438ef0b98cec6a by Abseil Team <absl-team@google.com>: Revert "absl: cap SpinLock backoff to 4ms" PiperOrigin-RevId: 222656230 -- 0d49538a3cab714156ed0a5651656c0aa098a1e5 by Abseil Team <absl-team@google.com>: Update absl/container/CMakeLists.txt to use new functions i.e. absl_cc_(library|test) PiperOrigin-RevId: 222535766 -- 92744e9d0e5c3bf9e1167a7bdf1a6777192531b1 by Abseil Team <absl-team@google.com>: Disable header parsing for broken targets PiperOrigin-RevId: 222257218 -- 39a6c623601c44e02d91e412f126a813d719507b by Abseil Team <absl-team@google.com>: absl: cap SpinLock backoff to 4ms The current backoff logic has 3 problems: 1. It can produce too high values (up to 256ms), which can negatively affect tail latency. The value was chosen long time ago and now it's a good idea to reconsider it. 2. It does not have low bound, so on any iteration it can produce a very small value that will lead to unnecessary cpu consumption. 3. It does not increase low bound with the number of iterations. So if the SpinLock is actually somehow locked for a very prolonged time, a waiter can still wake periodically. Rework the logic to solve these problems. Add lower bound of 128us, no code should rely on absence of episodic delays in this range as they can occur everywhere. Lower upper bound to 4ms. A thread sleeping for 4ms does not consume significant cpu time (see below). Grow lower bound with the number of iterations. This is cpu consumption of a process doing usleep(x) in a loop (sampled with ps): 64us -> 4.0% 128us -> 2.7% 256us -> 3.5% 512us -> 2.8% 1024us -> 1.6% 2048us -> 0.6% 4096us -> 0.3% 8192us -> 0.0% Few millisecond sleeps do not consume significant time. PiperOrigin-RevId: 222196086 -- 17104a2396ddda61fb0faed0a72ff8c161ca17ea by Shahriar Rouf <nafi@google.com>: Add benchmarks for hashing civil_times. PiperOrigin-RevId: 222152108 GitOrigin-RevId: 15d7bcf28220750db46930f4d8c090b54e3ae5fe Change-Id: I73b929feaf6ce72b70fdafd6108f53bbbeaf9738
6 years ago
struct AlignOf<Aligned<T, N>> {
static_assert(N % alignof(T) == 0,
"Custom alignment can't be lower than the type's alignment");
Export of internal Abseil changes. -- 15d7bcf28220750db46930f4d8c090b54e3ae5fe by Jon Cohen <cohenjon@google.com>: Fix miscellaneous CMake change interleaving issues for the daily release: * add back the absl::container target * Add copts to absl_cc_library targets in absl/container/CMakeLists.txt * Add trailing newline to the end of AbseilConfigureCopts.cmake PiperOrigin-RevId: 223057096 -- baac35470d75b6561477f688dc4eb021f604cf71 by Abseil Team <absl-team@google.com>: Internal Cleanup. PiperOrigin-RevId: 223051579 -- 6791c2f2e35b030b5579f36d3c607c6ba92fa089 by Abseil Team <absl-team@google.com>: Internal Change. PiperOrigin-RevId: 223046855 -- 5467ad987ea82aef77d2f1cc85aa9105e7d9c320 by Samuel Benzaquen <sbenza@google.com>: Workaround for gcc bug https://gcc.gnu.org/PR88115 PiperOrigin-RevId: 223041901 -- 36fa5cfd41df2b71d26487c45363901bbf6a2463 by Tom Manshreck <shreck@google.com>: Clarify visit() constraints PiperOrigin-RevId: 223032194 -- afdf4013de036b411db7f92cde8a2493e6665223 by Abseil Team <absl-team@google.com>: Fix comment typos. PiperOrigin-RevId: 223024090 -- e11c01927eb8b898f6633282824022104b258342 by Jon Cohen <cohenjon@google.com>: Make absl::spinlock_test_common TESTONLY This should fix https://github.com/abseil/abseil-cpp/issues/221 PiperOrigin-RevId: 222885323 -- 5ccc576d1c68e4b92705aa8064f1e8d715e5415e by Abseil Team <absl-team@google.com>: Internal change. PiperOrigin-RevId: 222877017 -- 96ff25bf78c4f4bca0d6e61faa4feeab91a2e73c by Jon Cohen <cohenjon@google.com>: Align CMake and Bazel compile options. This is the first step towards a single source of truth for Abseil compile options. Also makes absl_test and absl_cc_test make binaries and targets with compatible names to each other to make testing easier. PiperOrigin-RevId: 222858408 -- 7dd3e2618ad5a5de5d918fc73e438ef0b98cec6a by Abseil Team <absl-team@google.com>: Revert "absl: cap SpinLock backoff to 4ms" PiperOrigin-RevId: 222656230 -- 0d49538a3cab714156ed0a5651656c0aa098a1e5 by Abseil Team <absl-team@google.com>: Update absl/container/CMakeLists.txt to use new functions i.e. absl_cc_(library|test) PiperOrigin-RevId: 222535766 -- 92744e9d0e5c3bf9e1167a7bdf1a6777192531b1 by Abseil Team <absl-team@google.com>: Disable header parsing for broken targets PiperOrigin-RevId: 222257218 -- 39a6c623601c44e02d91e412f126a813d719507b by Abseil Team <absl-team@google.com>: absl: cap SpinLock backoff to 4ms The current backoff logic has 3 problems: 1. It can produce too high values (up to 256ms), which can negatively affect tail latency. The value was chosen long time ago and now it's a good idea to reconsider it. 2. It does not have low bound, so on any iteration it can produce a very small value that will lead to unnecessary cpu consumption. 3. It does not increase low bound with the number of iterations. So if the SpinLock is actually somehow locked for a very prolonged time, a waiter can still wake periodically. Rework the logic to solve these problems. Add lower bound of 128us, no code should rely on absence of episodic delays in this range as they can occur everywhere. Lower upper bound to 4ms. A thread sleeping for 4ms does not consume significant cpu time (see below). Grow lower bound with the number of iterations. This is cpu consumption of a process doing usleep(x) in a loop (sampled with ps): 64us -> 4.0% 128us -> 2.7% 256us -> 3.5% 512us -> 2.8% 1024us -> 1.6% 2048us -> 0.6% 4096us -> 0.3% 8192us -> 0.0% Few millisecond sleeps do not consume significant time. PiperOrigin-RevId: 222196086 -- 17104a2396ddda61fb0faed0a72ff8c161ca17ea by Shahriar Rouf <nafi@google.com>: Add benchmarks for hashing civil_times. PiperOrigin-RevId: 222152108 GitOrigin-RevId: 15d7bcf28220750db46930f4d8c090b54e3ae5fe Change-Id: I73b929feaf6ce72b70fdafd6108f53bbbeaf9738
6 years ago
static constexpr size_t value = N;
};
// Does `Ts...` contain `T`?
template <class T, class... Ts>
using Contains = absl::disjunction<std::is_same<T, Ts>...>;
template <class From, class To>
using CopyConst =
typename std::conditional<std::is_const<From>::value, const To, To>::type;
Export of internal Abseil changes. -- cd076f55c1fa600131f6dda392533dfe61679fc0 by Abseil Team <absl-team@google.com>: Internal change PiperOrigin-RevId: 224008762 -- e05f62b01286d51044ff86ec6ef565749b9faf82 by Abseil Team <absl-team@google.com>: Create a pow10() test helper function to compute guaranteed-precise double values of 10^x. Not all standard libraries ship bit-accurate pow() functions, causing tests to fail that rely on expected values generated by it. PiperOrigin-RevId: 223883762 -- fd88e5e3f7ab80f7f5df9fd1488cd58b4573be69 by Abseil Team <absl-team@google.com>: Remove some absl:: qualifications to work around inline namespace bugs on MSVC 2015. PiperOrigin-RevId: 223869642 -- 6276cfff969d596edd36a2bbaba65ee045808903 by Abseil Team <absl-team@google.com>: Update absl/memory/CMakeLists.txt to use new functions i.e. absl_cc_(library|test) PiperOrigin-RevId: 223854224 -- 359de9afc7a34c975fd3e0cbc52afd96637d97bd by Chris Kennelly <ckennelly@google.com>: Mark spinlock_benchmark_common as alwayslink = 1. PiperOrigin-RevId: 223844536 -- 450cd8cbe2789a6d54ed1eb87170259bb334f8b9 by Abseil Team <absl-team@google.com>: Support .* (pointer-to-member dereference) expressions in demangle.cc. PiperOrigin-RevId: 223826797 -- 772ca92179c3634f3e31a80bbc272ed8022e3572 by Abseil Team <absl-team@google.com>: Fix misspellings in absl::variant comments and replace a ' with a `. PiperOrigin-RevId: 223807911 -- 35dcdc2fbf299d195658aac101887f6dcad1de2f by Abseil Team <absl-team@google.com>: Bug fix in CMakeLists.txt file (SRCS --> HDRS). The compressed_tuple header-only library is being defined with the SRCS parameter instead of the HDRS parameter and this has been observed to cause some builds on some platforms to attempt to create a static library from it which fails since there are no .cc sources. PiperOrigin-RevId: 223805367 -- 4a57a3d2045bb137c0c97958e45ce425190b8d3e by Chris Kennelly <ckennelly@google.com>: Add test that absl::make_unique value initializes memory. PiperOrigin-RevId: 223801819 -- dfe8289d7f4dcc6bb568a26aaf192a89e896bdfd by Chris Kennelly <ckennelly@google.com>: SpinLock: Use exchange to avoid missing wakeups. The default fast path for SpinLock::Unlock does not use an atomic. If the SpinLock becomes contended while we are unlocking between lockword_.load and lockword_.store, we will fail to wake up the new waiter. This can cause unexpected latency spikes. PiperOrigin-RevId: 223800369 -- 9b9d35df786482f0016f77dd31691eff81503d23 by Abseil Team <absl-team@google.com>: Update absl/hash/CMakeLists.txt to use new functions i.e. absl_cc_(library|test) PiperOrigin-RevId: 223755819 -- c2014e2704b87e7cdce2d2a0287c7e2397752296 by Abseil Team <absl-team@google.com>: Update absl/debugging/CMakeLists.txt to use new functions i.e. absl_cc_(library|test) PiperOrigin-RevId: 223751986 -- d83a4e09126400e3fd80645cb03ee558f532271e by Derek Mauro <dmauro@google.com>: Cleanup synchronization benchmarks. PiperOrigin-RevId: 223589416 -- fad140b473586531b5b12843f942ec27dfcf5e93 by CJ Johnson <johnsoncj@google.com>: Makes unifies the order of forward_iterator and input_iterator overloads PiperOrigin-RevId: 223580660 -- 6cd7c96faa7cc5f79f574e35a1b13837ef187d05 by Abseil Team <absl-team@google.com>: Internal Change. PiperOrigin-RevId: 223561629 -- bd2e545356b0f548af0e3c14bb2f7f0e712e49d0 by Shaindel Schwartz <shaindel@google.com>: Remove misleading comments. try_emplace() does not exist for the hash_set containers. PiperOrigin-RevId: 223543089 -- 0cd380a53b587eb7aacc4003a4a3bbb6c78d7c10 by Derek Mauro <dmauro@google.com>: Internal change PiperOrigin-RevId: 223512551 -- 7156dfee599cb72e9adddfe0e6ae07a95ddf10bb by Greg Miller <jgm@google.com>: Fixes UB that would result from constructing, multiplying, or dividing a Duration with a double "NaN" value. This CL changes the absl::Duration *implementation* to return an InfiniteDuration value that has the same sign as the given NaN. PiperOrigin-RevId: 223407499 -- 196b7d18609958267951882baf7f9429e49bcafa by CJ Johnson <johnsoncj@google.com>: Addresses NVCC+MSVC compilation bug where `inlined_capacity()` was not considered valid in constexpr PiperOrigin-RevId: 223397718 GitOrigin-RevId: cd076f55c1fa600131f6dda392533dfe61679fc0 Change-Id: I5423ca6470f661a7c6f73aa8fee49990446f157f
6 years ago
// Note: We're not qualifying this with absl:: because it doesn't compile under
// MSVC.
template <class T>
Export of internal Abseil changes. -- cd076f55c1fa600131f6dda392533dfe61679fc0 by Abseil Team <absl-team@google.com>: Internal change PiperOrigin-RevId: 224008762 -- e05f62b01286d51044ff86ec6ef565749b9faf82 by Abseil Team <absl-team@google.com>: Create a pow10() test helper function to compute guaranteed-precise double values of 10^x. Not all standard libraries ship bit-accurate pow() functions, causing tests to fail that rely on expected values generated by it. PiperOrigin-RevId: 223883762 -- fd88e5e3f7ab80f7f5df9fd1488cd58b4573be69 by Abseil Team <absl-team@google.com>: Remove some absl:: qualifications to work around inline namespace bugs on MSVC 2015. PiperOrigin-RevId: 223869642 -- 6276cfff969d596edd36a2bbaba65ee045808903 by Abseil Team <absl-team@google.com>: Update absl/memory/CMakeLists.txt to use new functions i.e. absl_cc_(library|test) PiperOrigin-RevId: 223854224 -- 359de9afc7a34c975fd3e0cbc52afd96637d97bd by Chris Kennelly <ckennelly@google.com>: Mark spinlock_benchmark_common as alwayslink = 1. PiperOrigin-RevId: 223844536 -- 450cd8cbe2789a6d54ed1eb87170259bb334f8b9 by Abseil Team <absl-team@google.com>: Support .* (pointer-to-member dereference) expressions in demangle.cc. PiperOrigin-RevId: 223826797 -- 772ca92179c3634f3e31a80bbc272ed8022e3572 by Abseil Team <absl-team@google.com>: Fix misspellings in absl::variant comments and replace a ' with a `. PiperOrigin-RevId: 223807911 -- 35dcdc2fbf299d195658aac101887f6dcad1de2f by Abseil Team <absl-team@google.com>: Bug fix in CMakeLists.txt file (SRCS --> HDRS). The compressed_tuple header-only library is being defined with the SRCS parameter instead of the HDRS parameter and this has been observed to cause some builds on some platforms to attempt to create a static library from it which fails since there are no .cc sources. PiperOrigin-RevId: 223805367 -- 4a57a3d2045bb137c0c97958e45ce425190b8d3e by Chris Kennelly <ckennelly@google.com>: Add test that absl::make_unique value initializes memory. PiperOrigin-RevId: 223801819 -- dfe8289d7f4dcc6bb568a26aaf192a89e896bdfd by Chris Kennelly <ckennelly@google.com>: SpinLock: Use exchange to avoid missing wakeups. The default fast path for SpinLock::Unlock does not use an atomic. If the SpinLock becomes contended while we are unlocking between lockword_.load and lockword_.store, we will fail to wake up the new waiter. This can cause unexpected latency spikes. PiperOrigin-RevId: 223800369 -- 9b9d35df786482f0016f77dd31691eff81503d23 by Abseil Team <absl-team@google.com>: Update absl/hash/CMakeLists.txt to use new functions i.e. absl_cc_(library|test) PiperOrigin-RevId: 223755819 -- c2014e2704b87e7cdce2d2a0287c7e2397752296 by Abseil Team <absl-team@google.com>: Update absl/debugging/CMakeLists.txt to use new functions i.e. absl_cc_(library|test) PiperOrigin-RevId: 223751986 -- d83a4e09126400e3fd80645cb03ee558f532271e by Derek Mauro <dmauro@google.com>: Cleanup synchronization benchmarks. PiperOrigin-RevId: 223589416 -- fad140b473586531b5b12843f942ec27dfcf5e93 by CJ Johnson <johnsoncj@google.com>: Makes unifies the order of forward_iterator and input_iterator overloads PiperOrigin-RevId: 223580660 -- 6cd7c96faa7cc5f79f574e35a1b13837ef187d05 by Abseil Team <absl-team@google.com>: Internal Change. PiperOrigin-RevId: 223561629 -- bd2e545356b0f548af0e3c14bb2f7f0e712e49d0 by Shaindel Schwartz <shaindel@google.com>: Remove misleading comments. try_emplace() does not exist for the hash_set containers. PiperOrigin-RevId: 223543089 -- 0cd380a53b587eb7aacc4003a4a3bbb6c78d7c10 by Derek Mauro <dmauro@google.com>: Internal change PiperOrigin-RevId: 223512551 -- 7156dfee599cb72e9adddfe0e6ae07a95ddf10bb by Greg Miller <jgm@google.com>: Fixes UB that would result from constructing, multiplying, or dividing a Duration with a double "NaN" value. This CL changes the absl::Duration *implementation* to return an InfiniteDuration value that has the same sign as the given NaN. PiperOrigin-RevId: 223407499 -- 196b7d18609958267951882baf7f9429e49bcafa by CJ Johnson <johnsoncj@google.com>: Addresses NVCC+MSVC compilation bug where `inlined_capacity()` was not considered valid in constexpr PiperOrigin-RevId: 223397718 GitOrigin-RevId: cd076f55c1fa600131f6dda392533dfe61679fc0 Change-Id: I5423ca6470f661a7c6f73aa8fee49990446f157f
6 years ago
using SliceType = Span<T>;
// This namespace contains no types. It prevents functions defined in it from
// being found by ADL.
namespace adl_barrier {
template <class Needle, class... Ts>
constexpr size_t Find(Needle, Needle, Ts...) {
static_assert(!Contains<Needle, Ts...>(), "Duplicate element type");
return 0;
}
template <class Needle, class T, class... Ts>
constexpr size_t Find(Needle, T, Ts...) {
return adl_barrier::Find(Needle(), Ts()...) + 1;
}
constexpr bool IsPow2(size_t n) { return !(n & (n - 1)); }
// Returns `q * m` for the smallest `q` such that `q * m >= n`.
// Requires: `m` is a power of two. It's enforced by IsLegalElementType below.
constexpr size_t Align(size_t n, size_t m) { return (n + m - 1) & ~(m - 1); }
constexpr size_t Min(size_t a, size_t b) { return b < a ? b : a; }
constexpr size_t Max(size_t a) { return a; }
template <class... Ts>
constexpr size_t Max(size_t a, size_t b, Ts... rest) {
return adl_barrier::Max(b < a ? a : b, rest...);
}
template <class T>
std::string TypeName() {
std::string out;
int status = 0;
char* demangled = nullptr;
#ifdef ABSL_INTERNAL_HAS_CXA_DEMANGLE
demangled = abi::__cxa_demangle(typeid(T).name(), nullptr, nullptr, &status);
#endif
Export of internal Abseil changes. -- 15d7bcf28220750db46930f4d8c090b54e3ae5fe by Jon Cohen <cohenjon@google.com>: Fix miscellaneous CMake change interleaving issues for the daily release: * add back the absl::container target * Add copts to absl_cc_library targets in absl/container/CMakeLists.txt * Add trailing newline to the end of AbseilConfigureCopts.cmake PiperOrigin-RevId: 223057096 -- baac35470d75b6561477f688dc4eb021f604cf71 by Abseil Team <absl-team@google.com>: Internal Cleanup. PiperOrigin-RevId: 223051579 -- 6791c2f2e35b030b5579f36d3c607c6ba92fa089 by Abseil Team <absl-team@google.com>: Internal Change. PiperOrigin-RevId: 223046855 -- 5467ad987ea82aef77d2f1cc85aa9105e7d9c320 by Samuel Benzaquen <sbenza@google.com>: Workaround for gcc bug https://gcc.gnu.org/PR88115 PiperOrigin-RevId: 223041901 -- 36fa5cfd41df2b71d26487c45363901bbf6a2463 by Tom Manshreck <shreck@google.com>: Clarify visit() constraints PiperOrigin-RevId: 223032194 -- afdf4013de036b411db7f92cde8a2493e6665223 by Abseil Team <absl-team@google.com>: Fix comment typos. PiperOrigin-RevId: 223024090 -- e11c01927eb8b898f6633282824022104b258342 by Jon Cohen <cohenjon@google.com>: Make absl::spinlock_test_common TESTONLY This should fix https://github.com/abseil/abseil-cpp/issues/221 PiperOrigin-RevId: 222885323 -- 5ccc576d1c68e4b92705aa8064f1e8d715e5415e by Abseil Team <absl-team@google.com>: Internal change. PiperOrigin-RevId: 222877017 -- 96ff25bf78c4f4bca0d6e61faa4feeab91a2e73c by Jon Cohen <cohenjon@google.com>: Align CMake and Bazel compile options. This is the first step towards a single source of truth for Abseil compile options. Also makes absl_test and absl_cc_test make binaries and targets with compatible names to each other to make testing easier. PiperOrigin-RevId: 222858408 -- 7dd3e2618ad5a5de5d918fc73e438ef0b98cec6a by Abseil Team <absl-team@google.com>: Revert "absl: cap SpinLock backoff to 4ms" PiperOrigin-RevId: 222656230 -- 0d49538a3cab714156ed0a5651656c0aa098a1e5 by Abseil Team <absl-team@google.com>: Update absl/container/CMakeLists.txt to use new functions i.e. absl_cc_(library|test) PiperOrigin-RevId: 222535766 -- 92744e9d0e5c3bf9e1167a7bdf1a6777192531b1 by Abseil Team <absl-team@google.com>: Disable header parsing for broken targets PiperOrigin-RevId: 222257218 -- 39a6c623601c44e02d91e412f126a813d719507b by Abseil Team <absl-team@google.com>: absl: cap SpinLock backoff to 4ms The current backoff logic has 3 problems: 1. It can produce too high values (up to 256ms), which can negatively affect tail latency. The value was chosen long time ago and now it's a good idea to reconsider it. 2. It does not have low bound, so on any iteration it can produce a very small value that will lead to unnecessary cpu consumption. 3. It does not increase low bound with the number of iterations. So if the SpinLock is actually somehow locked for a very prolonged time, a waiter can still wake periodically. Rework the logic to solve these problems. Add lower bound of 128us, no code should rely on absence of episodic delays in this range as they can occur everywhere. Lower upper bound to 4ms. A thread sleeping for 4ms does not consume significant cpu time (see below). Grow lower bound with the number of iterations. This is cpu consumption of a process doing usleep(x) in a loop (sampled with ps): 64us -> 4.0% 128us -> 2.7% 256us -> 3.5% 512us -> 2.8% 1024us -> 1.6% 2048us -> 0.6% 4096us -> 0.3% 8192us -> 0.0% Few millisecond sleeps do not consume significant time. PiperOrigin-RevId: 222196086 -- 17104a2396ddda61fb0faed0a72ff8c161ca17ea by Shahriar Rouf <nafi@google.com>: Add benchmarks for hashing civil_times. PiperOrigin-RevId: 222152108 GitOrigin-RevId: 15d7bcf28220750db46930f4d8c090b54e3ae5fe Change-Id: I73b929feaf6ce72b70fdafd6108f53bbbeaf9738
6 years ago
if (status == 0 && demangled != nullptr) { // Demangling succeeded.
absl::StrAppend(&out, "<", demangled, ">");
free(demangled);
} else {
#if defined(__GXX_RTTI) || defined(_CPPRTTI)
absl::StrAppend(&out, "<", typeid(T).name(), ">");
#endif
}
return out;
}
} // namespace adl_barrier
template <bool C>
using EnableIf = typename std::enable_if<C, int>::type;
// Can `T` be a template argument of `Layout`?
template <class T>
using IsLegalElementType = std::integral_constant<
bool, !std::is_reference<T>::value && !std::is_volatile<T>::value &&
!std::is_reference<typename Type<T>::type>::value &&
!std::is_volatile<typename Type<T>::type>::value &&
adl_barrier::IsPow2(AlignOf<T>::value)>;
template <class Elements, class SizeSeq, class OffsetSeq>
class LayoutImpl;
// Public base class of `Layout` and the result type of `Layout::Partial()`.
//
// `Elements...` contains all template arguments of `Layout` that created this
// instance.
//
// `SizeSeq...` is `[0, NumSizes)` where `NumSizes` is the number of arguments
// passed to `Layout::Partial()` or `Layout::Layout()`.
//
// `OffsetSeq...` is `[0, NumOffsets)` where `NumOffsets` is
// `Min(sizeof...(Elements), NumSizes + 1)` (the number of arrays for which we
// can compute offsets).
template <class... Elements, size_t... SizeSeq, size_t... OffsetSeq>
class LayoutImpl<std::tuple<Elements...>, absl::index_sequence<SizeSeq...>,
absl::index_sequence<OffsetSeq...>> {
private:
static_assert(sizeof...(Elements) > 0, "At least one field is required");
static_assert(absl::conjunction<IsLegalElementType<Elements>...>::value,
"Invalid element type (see IsLegalElementType)");
enum {
NumTypes = sizeof...(Elements),
NumSizes = sizeof...(SizeSeq),
NumOffsets = sizeof...(OffsetSeq),
};
// These are guaranteed by `Layout`.
static_assert(NumOffsets == adl_barrier::Min(NumTypes, NumSizes + 1),
"Internal error");
static_assert(NumTypes > 0, "Internal error");
// Returns the index of `T` in `Elements...`. Results in a compilation error
// if `Elements...` doesn't contain exactly one instance of `T`.
template <class T>
static constexpr size_t ElementIndex() {
static_assert(Contains<Type<T>, Type<typename Type<Elements>::type>...>(),
"Type not found");
return adl_barrier::Find(Type<T>(),
Type<typename Type<Elements>::type>()...);
}
template <size_t N>
using ElementAlignment =
AlignOf<typename std::tuple_element<N, std::tuple<Elements...>>::type>;
public:
// Element types of all arrays packed in a tuple.
using ElementTypes = std::tuple<typename Type<Elements>::type...>;
// Element type of the Nth array.
template <size_t N>
using ElementType = typename std::tuple_element<N, ElementTypes>::type;
constexpr explicit LayoutImpl(IntToSize<SizeSeq>... sizes)
: size_{sizes...} {}
// Alignment of the layout, equal to the strictest alignment of all elements.
// All pointers passed to the methods of layout must be aligned to this value.
static constexpr size_t Alignment() {
return adl_barrier::Max(AlignOf<Elements>::value...);
}
// Offset in bytes of the Nth array.
//
// // int[3], 4 bytes of padding, double[4].
// Layout<int, double> x(3, 4);
// assert(x.Offset<0>() == 0); // The ints starts from 0.
// assert(x.Offset<1>() == 16); // The doubles starts from 16.
//
// Requires: `N <= NumSizes && N < sizeof...(Ts)`.
template <size_t N, EnableIf<N == 0> = 0>
constexpr size_t Offset() const {
return 0;
}
template <size_t N, EnableIf<N != 0> = 0>
constexpr size_t Offset() const {
static_assert(N < NumOffsets, "Index out of bounds");
return adl_barrier::Align(
Offset<N - 1>() + SizeOf<ElementType<N - 1>>() * size_[N - 1],
Export of internal Abseil changes. -- 15d7bcf28220750db46930f4d8c090b54e3ae5fe by Jon Cohen <cohenjon@google.com>: Fix miscellaneous CMake change interleaving issues for the daily release: * add back the absl::container target * Add copts to absl_cc_library targets in absl/container/CMakeLists.txt * Add trailing newline to the end of AbseilConfigureCopts.cmake PiperOrigin-RevId: 223057096 -- baac35470d75b6561477f688dc4eb021f604cf71 by Abseil Team <absl-team@google.com>: Internal Cleanup. PiperOrigin-RevId: 223051579 -- 6791c2f2e35b030b5579f36d3c607c6ba92fa089 by Abseil Team <absl-team@google.com>: Internal Change. PiperOrigin-RevId: 223046855 -- 5467ad987ea82aef77d2f1cc85aa9105e7d9c320 by Samuel Benzaquen <sbenza@google.com>: Workaround for gcc bug https://gcc.gnu.org/PR88115 PiperOrigin-RevId: 223041901 -- 36fa5cfd41df2b71d26487c45363901bbf6a2463 by Tom Manshreck <shreck@google.com>: Clarify visit() constraints PiperOrigin-RevId: 223032194 -- afdf4013de036b411db7f92cde8a2493e6665223 by Abseil Team <absl-team@google.com>: Fix comment typos. PiperOrigin-RevId: 223024090 -- e11c01927eb8b898f6633282824022104b258342 by Jon Cohen <cohenjon@google.com>: Make absl::spinlock_test_common TESTONLY This should fix https://github.com/abseil/abseil-cpp/issues/221 PiperOrigin-RevId: 222885323 -- 5ccc576d1c68e4b92705aa8064f1e8d715e5415e by Abseil Team <absl-team@google.com>: Internal change. PiperOrigin-RevId: 222877017 -- 96ff25bf78c4f4bca0d6e61faa4feeab91a2e73c by Jon Cohen <cohenjon@google.com>: Align CMake and Bazel compile options. This is the first step towards a single source of truth for Abseil compile options. Also makes absl_test and absl_cc_test make binaries and targets with compatible names to each other to make testing easier. PiperOrigin-RevId: 222858408 -- 7dd3e2618ad5a5de5d918fc73e438ef0b98cec6a by Abseil Team <absl-team@google.com>: Revert "absl: cap SpinLock backoff to 4ms" PiperOrigin-RevId: 222656230 -- 0d49538a3cab714156ed0a5651656c0aa098a1e5 by Abseil Team <absl-team@google.com>: Update absl/container/CMakeLists.txt to use new functions i.e. absl_cc_(library|test) PiperOrigin-RevId: 222535766 -- 92744e9d0e5c3bf9e1167a7bdf1a6777192531b1 by Abseil Team <absl-team@google.com>: Disable header parsing for broken targets PiperOrigin-RevId: 222257218 -- 39a6c623601c44e02d91e412f126a813d719507b by Abseil Team <absl-team@google.com>: absl: cap SpinLock backoff to 4ms The current backoff logic has 3 problems: 1. It can produce too high values (up to 256ms), which can negatively affect tail latency. The value was chosen long time ago and now it's a good idea to reconsider it. 2. It does not have low bound, so on any iteration it can produce a very small value that will lead to unnecessary cpu consumption. 3. It does not increase low bound with the number of iterations. So if the SpinLock is actually somehow locked for a very prolonged time, a waiter can still wake periodically. Rework the logic to solve these problems. Add lower bound of 128us, no code should rely on absence of episodic delays in this range as they can occur everywhere. Lower upper bound to 4ms. A thread sleeping for 4ms does not consume significant cpu time (see below). Grow lower bound with the number of iterations. This is cpu consumption of a process doing usleep(x) in a loop (sampled with ps): 64us -> 4.0% 128us -> 2.7% 256us -> 3.5% 512us -> 2.8% 1024us -> 1.6% 2048us -> 0.6% 4096us -> 0.3% 8192us -> 0.0% Few millisecond sleeps do not consume significant time. PiperOrigin-RevId: 222196086 -- 17104a2396ddda61fb0faed0a72ff8c161ca17ea by Shahriar Rouf <nafi@google.com>: Add benchmarks for hashing civil_times. PiperOrigin-RevId: 222152108 GitOrigin-RevId: 15d7bcf28220750db46930f4d8c090b54e3ae5fe Change-Id: I73b929feaf6ce72b70fdafd6108f53bbbeaf9738
6 years ago
ElementAlignment<N>::value);
}
// Offset in bytes of the array with the specified element type. There must
// be exactly one such array and its zero-based index must be at most
// `NumSizes`.
//
// // int[3], 4 bytes of padding, double[4].
// Layout<int, double> x(3, 4);
// assert(x.Offset<int>() == 0); // The ints starts from 0.
// assert(x.Offset<double>() == 16); // The doubles starts from 16.
template <class T>
constexpr size_t Offset() const {
return Offset<ElementIndex<T>()>();
}
// Offsets in bytes of all arrays for which the offsets are known.
constexpr std::array<size_t, NumOffsets> Offsets() const {
return {{Offset<OffsetSeq>()...}};
}
// The number of elements in the Nth array. This is the Nth argument of
// `Layout::Partial()` or `Layout::Layout()` (zero-based).
//
// // int[3], 4 bytes of padding, double[4].
// Layout<int, double> x(3, 4);
// assert(x.Size<0>() == 3);
// assert(x.Size<1>() == 4);
//
// Requires: `N < NumSizes`.
template <size_t N>
constexpr size_t Size() const {
static_assert(N < NumSizes, "Index out of bounds");
return size_[N];
}
// The number of elements in the array with the specified element type.
// There must be exactly one such array and its zero-based index must be
// at most `NumSizes`.
//
// // int[3], 4 bytes of padding, double[4].
// Layout<int, double> x(3, 4);
// assert(x.Size<int>() == 3);
// assert(x.Size<double>() == 4);
template <class T>
constexpr size_t Size() const {
return Size<ElementIndex<T>()>();
}
Export of internal Abseil changes. -- 15d7bcf28220750db46930f4d8c090b54e3ae5fe by Jon Cohen <cohenjon@google.com>: Fix miscellaneous CMake change interleaving issues for the daily release: * add back the absl::container target * Add copts to absl_cc_library targets in absl/container/CMakeLists.txt * Add trailing newline to the end of AbseilConfigureCopts.cmake PiperOrigin-RevId: 223057096 -- baac35470d75b6561477f688dc4eb021f604cf71 by Abseil Team <absl-team@google.com>: Internal Cleanup. PiperOrigin-RevId: 223051579 -- 6791c2f2e35b030b5579f36d3c607c6ba92fa089 by Abseil Team <absl-team@google.com>: Internal Change. PiperOrigin-RevId: 223046855 -- 5467ad987ea82aef77d2f1cc85aa9105e7d9c320 by Samuel Benzaquen <sbenza@google.com>: Workaround for gcc bug https://gcc.gnu.org/PR88115 PiperOrigin-RevId: 223041901 -- 36fa5cfd41df2b71d26487c45363901bbf6a2463 by Tom Manshreck <shreck@google.com>: Clarify visit() constraints PiperOrigin-RevId: 223032194 -- afdf4013de036b411db7f92cde8a2493e6665223 by Abseil Team <absl-team@google.com>: Fix comment typos. PiperOrigin-RevId: 223024090 -- e11c01927eb8b898f6633282824022104b258342 by Jon Cohen <cohenjon@google.com>: Make absl::spinlock_test_common TESTONLY This should fix https://github.com/abseil/abseil-cpp/issues/221 PiperOrigin-RevId: 222885323 -- 5ccc576d1c68e4b92705aa8064f1e8d715e5415e by Abseil Team <absl-team@google.com>: Internal change. PiperOrigin-RevId: 222877017 -- 96ff25bf78c4f4bca0d6e61faa4feeab91a2e73c by Jon Cohen <cohenjon@google.com>: Align CMake and Bazel compile options. This is the first step towards a single source of truth for Abseil compile options. Also makes absl_test and absl_cc_test make binaries and targets with compatible names to each other to make testing easier. PiperOrigin-RevId: 222858408 -- 7dd3e2618ad5a5de5d918fc73e438ef0b98cec6a by Abseil Team <absl-team@google.com>: Revert "absl: cap SpinLock backoff to 4ms" PiperOrigin-RevId: 222656230 -- 0d49538a3cab714156ed0a5651656c0aa098a1e5 by Abseil Team <absl-team@google.com>: Update absl/container/CMakeLists.txt to use new functions i.e. absl_cc_(library|test) PiperOrigin-RevId: 222535766 -- 92744e9d0e5c3bf9e1167a7bdf1a6777192531b1 by Abseil Team <absl-team@google.com>: Disable header parsing for broken targets PiperOrigin-RevId: 222257218 -- 39a6c623601c44e02d91e412f126a813d719507b by Abseil Team <absl-team@google.com>: absl: cap SpinLock backoff to 4ms The current backoff logic has 3 problems: 1. It can produce too high values (up to 256ms), which can negatively affect tail latency. The value was chosen long time ago and now it's a good idea to reconsider it. 2. It does not have low bound, so on any iteration it can produce a very small value that will lead to unnecessary cpu consumption. 3. It does not increase low bound with the number of iterations. So if the SpinLock is actually somehow locked for a very prolonged time, a waiter can still wake periodically. Rework the logic to solve these problems. Add lower bound of 128us, no code should rely on absence of episodic delays in this range as they can occur everywhere. Lower upper bound to 4ms. A thread sleeping for 4ms does not consume significant cpu time (see below). Grow lower bound with the number of iterations. This is cpu consumption of a process doing usleep(x) in a loop (sampled with ps): 64us -> 4.0% 128us -> 2.7% 256us -> 3.5% 512us -> 2.8% 1024us -> 1.6% 2048us -> 0.6% 4096us -> 0.3% 8192us -> 0.0% Few millisecond sleeps do not consume significant time. PiperOrigin-RevId: 222196086 -- 17104a2396ddda61fb0faed0a72ff8c161ca17ea by Shahriar Rouf <nafi@google.com>: Add benchmarks for hashing civil_times. PiperOrigin-RevId: 222152108 GitOrigin-RevId: 15d7bcf28220750db46930f4d8c090b54e3ae5fe Change-Id: I73b929feaf6ce72b70fdafd6108f53bbbeaf9738
6 years ago
// The number of elements of all arrays for which they are known.
constexpr std::array<size_t, NumSizes> Sizes() const {
return {{Size<SizeSeq>()...}};
}
// Pointer to the beginning of the Nth array.
//
// `Char` must be `[const] [signed|unsigned] char`.
//
// // int[3], 4 bytes of padding, double[4].
// Layout<int, double> x(3, 4);
// unsigned char* p = new unsigned char[x.AllocSize()];
// int* ints = x.Pointer<0>(p);
// double* doubles = x.Pointer<1>(p);
//
// Requires: `N <= NumSizes && N < sizeof...(Ts)`.
// Requires: `p` is aligned to `Alignment()`.
template <size_t N, class Char>
CopyConst<Char, ElementType<N>>* Pointer(Char* p) const {
using C = typename std::remove_const<Char>::type;
static_assert(
std::is_same<C, char>() || std::is_same<C, unsigned char>() ||
std::is_same<C, signed char>(),
"The argument must be a pointer to [const] [signed|unsigned] char");
constexpr size_t alignment = Alignment();
(void)alignment;
assert(reinterpret_cast<uintptr_t>(p) % alignment == 0);
return reinterpret_cast<CopyConst<Char, ElementType<N>>*>(p + Offset<N>());
}
// Pointer to the beginning of the array with the specified element type.
// There must be exactly one such array and its zero-based index must be at
// most `NumSizes`.
//
// `Char` must be `[const] [signed|unsigned] char`.
//
// // int[3], 4 bytes of padding, double[4].
// Layout<int, double> x(3, 4);
// unsigned char* p = new unsigned char[x.AllocSize()];
// int* ints = x.Pointer<int>(p);
// double* doubles = x.Pointer<double>(p);
//
// Requires: `p` is aligned to `Alignment()`.
template <class T, class Char>
CopyConst<Char, T>* Pointer(Char* p) const {
return Pointer<ElementIndex<T>()>(p);
}
// Pointers to all arrays for which pointers are known.
//
// `Char` must be `[const] [signed|unsigned] char`.
//
// // int[3], 4 bytes of padding, double[4].
// Layout<int, double> x(3, 4);
// unsigned char* p = new unsigned char[x.AllocSize()];
//
// int* ints;
// double* doubles;
// std::tie(ints, doubles) = x.Pointers(p);
//
// Requires: `p` is aligned to `Alignment()`.
//
// Note: We're not using ElementType alias here because it does not compile
// under MSVC.
template <class Char>
std::tuple<CopyConst<
Char, typename std::tuple_element<OffsetSeq, ElementTypes>::type>*...>
Pointers(Char* p) const {
return std::tuple<CopyConst<Char, ElementType<OffsetSeq>>*...>(
Pointer<OffsetSeq>(p)...);
}
// The Nth array.
//
// `Char` must be `[const] [signed|unsigned] char`.
//
// // int[3], 4 bytes of padding, double[4].
// Layout<int, double> x(3, 4);
// unsigned char* p = new unsigned char[x.AllocSize()];
// Span<int> ints = x.Slice<0>(p);
// Span<double> doubles = x.Slice<1>(p);
//
// Requires: `N < NumSizes`.
// Requires: `p` is aligned to `Alignment()`.
template <size_t N, class Char>
SliceType<CopyConst<Char, ElementType<N>>> Slice(Char* p) const {
return SliceType<CopyConst<Char, ElementType<N>>>(Pointer<N>(p), Size<N>());
}
// The array with the specified element type. There must be exactly one
// such array and its zero-based index must be less than `NumSizes`.
//
// `Char` must be `[const] [signed|unsigned] char`.
//
// // int[3], 4 bytes of padding, double[4].
// Layout<int, double> x(3, 4);
// unsigned char* p = new unsigned char[x.AllocSize()];
// Span<int> ints = x.Slice<int>(p);
// Span<double> doubles = x.Slice<double>(p);
//
// Requires: `p` is aligned to `Alignment()`.
template <class T, class Char>
SliceType<CopyConst<Char, T>> Slice(Char* p) const {
return Slice<ElementIndex<T>()>(p);
}
// All arrays with known sizes.
//
// `Char` must be `[const] [signed|unsigned] char`.
//
// // int[3], 4 bytes of padding, double[4].
// Layout<int, double> x(3, 4);
// unsigned char* p = new unsigned char[x.AllocSize()];
//
// Span<int> ints;
// Span<double> doubles;
// std::tie(ints, doubles) = x.Slices(p);
//
// Requires: `p` is aligned to `Alignment()`.
//
// Note: We're not using ElementType alias here because it does not compile
// under MSVC.
template <class Char>
std::tuple<SliceType<CopyConst<
Char, typename std::tuple_element<SizeSeq, ElementTypes>::type>>...>
Slices(Char* p) const {
// Workaround for https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63875 (fixed
// in 6.1).
(void)p;
return std::tuple<SliceType<CopyConst<Char, ElementType<SizeSeq>>>...>(
Slice<SizeSeq>(p)...);
}
// The size of the allocation that fits all arrays.
//
// // int[3], 4 bytes of padding, double[4].
// Layout<int, double> x(3, 4);
// unsigned char* p = new unsigned char[x.AllocSize()]; // 48 bytes
//
// Requires: `NumSizes == sizeof...(Ts)`.
constexpr size_t AllocSize() const {
static_assert(NumTypes == NumSizes, "You must specify sizes of all fields");
return Offset<NumTypes - 1>() +
SizeOf<ElementType<NumTypes - 1>>() * size_[NumTypes - 1];
}
// If built with --config=asan, poisons padding bytes (if any) in the
// allocation. The pointer must point to a memory block at least
// `AllocSize()` bytes in length.
//
// `Char` must be `[const] [signed|unsigned] char`.
//
// Requires: `p` is aligned to `Alignment()`.
template <class Char, size_t N = NumOffsets - 1, EnableIf<N == 0> = 0>
void PoisonPadding(const Char* p) const {
Pointer<0>(p); // verify the requirements on `Char` and `p`
}
template <class Char, size_t N = NumOffsets - 1, EnableIf<N != 0> = 0>
void PoisonPadding(const Char* p) const {
static_assert(N < NumOffsets, "Index out of bounds");
(void)p;
#ifdef ADDRESS_SANITIZER
PoisonPadding<Char, N - 1>(p);
// The `if` is an optimization. It doesn't affect the observable behaviour.
Export of internal Abseil changes. -- 15d7bcf28220750db46930f4d8c090b54e3ae5fe by Jon Cohen <cohenjon@google.com>: Fix miscellaneous CMake change interleaving issues for the daily release: * add back the absl::container target * Add copts to absl_cc_library targets in absl/container/CMakeLists.txt * Add trailing newline to the end of AbseilConfigureCopts.cmake PiperOrigin-RevId: 223057096 -- baac35470d75b6561477f688dc4eb021f604cf71 by Abseil Team <absl-team@google.com>: Internal Cleanup. PiperOrigin-RevId: 223051579 -- 6791c2f2e35b030b5579f36d3c607c6ba92fa089 by Abseil Team <absl-team@google.com>: Internal Change. PiperOrigin-RevId: 223046855 -- 5467ad987ea82aef77d2f1cc85aa9105e7d9c320 by Samuel Benzaquen <sbenza@google.com>: Workaround for gcc bug https://gcc.gnu.org/PR88115 PiperOrigin-RevId: 223041901 -- 36fa5cfd41df2b71d26487c45363901bbf6a2463 by Tom Manshreck <shreck@google.com>: Clarify visit() constraints PiperOrigin-RevId: 223032194 -- afdf4013de036b411db7f92cde8a2493e6665223 by Abseil Team <absl-team@google.com>: Fix comment typos. PiperOrigin-RevId: 223024090 -- e11c01927eb8b898f6633282824022104b258342 by Jon Cohen <cohenjon@google.com>: Make absl::spinlock_test_common TESTONLY This should fix https://github.com/abseil/abseil-cpp/issues/221 PiperOrigin-RevId: 222885323 -- 5ccc576d1c68e4b92705aa8064f1e8d715e5415e by Abseil Team <absl-team@google.com>: Internal change. PiperOrigin-RevId: 222877017 -- 96ff25bf78c4f4bca0d6e61faa4feeab91a2e73c by Jon Cohen <cohenjon@google.com>: Align CMake and Bazel compile options. This is the first step towards a single source of truth for Abseil compile options. Also makes absl_test and absl_cc_test make binaries and targets with compatible names to each other to make testing easier. PiperOrigin-RevId: 222858408 -- 7dd3e2618ad5a5de5d918fc73e438ef0b98cec6a by Abseil Team <absl-team@google.com>: Revert "absl: cap SpinLock backoff to 4ms" PiperOrigin-RevId: 222656230 -- 0d49538a3cab714156ed0a5651656c0aa098a1e5 by Abseil Team <absl-team@google.com>: Update absl/container/CMakeLists.txt to use new functions i.e. absl_cc_(library|test) PiperOrigin-RevId: 222535766 -- 92744e9d0e5c3bf9e1167a7bdf1a6777192531b1 by Abseil Team <absl-team@google.com>: Disable header parsing for broken targets PiperOrigin-RevId: 222257218 -- 39a6c623601c44e02d91e412f126a813d719507b by Abseil Team <absl-team@google.com>: absl: cap SpinLock backoff to 4ms The current backoff logic has 3 problems: 1. It can produce too high values (up to 256ms), which can negatively affect tail latency. The value was chosen long time ago and now it's a good idea to reconsider it. 2. It does not have low bound, so on any iteration it can produce a very small value that will lead to unnecessary cpu consumption. 3. It does not increase low bound with the number of iterations. So if the SpinLock is actually somehow locked for a very prolonged time, a waiter can still wake periodically. Rework the logic to solve these problems. Add lower bound of 128us, no code should rely on absence of episodic delays in this range as they can occur everywhere. Lower upper bound to 4ms. A thread sleeping for 4ms does not consume significant cpu time (see below). Grow lower bound with the number of iterations. This is cpu consumption of a process doing usleep(x) in a loop (sampled with ps): 64us -> 4.0% 128us -> 2.7% 256us -> 3.5% 512us -> 2.8% 1024us -> 1.6% 2048us -> 0.6% 4096us -> 0.3% 8192us -> 0.0% Few millisecond sleeps do not consume significant time. PiperOrigin-RevId: 222196086 -- 17104a2396ddda61fb0faed0a72ff8c161ca17ea by Shahriar Rouf <nafi@google.com>: Add benchmarks for hashing civil_times. PiperOrigin-RevId: 222152108 GitOrigin-RevId: 15d7bcf28220750db46930f4d8c090b54e3ae5fe Change-Id: I73b929feaf6ce72b70fdafd6108f53bbbeaf9738
6 years ago
if (ElementAlignment<N - 1>::value % ElementAlignment<N>::value) {
size_t start =
Offset<N - 1>() + SizeOf<ElementType<N - 1>>() * size_[N - 1];
ASAN_POISON_MEMORY_REGION(p + start, Offset<N>() - start);
}
#endif
}
// Human-readable description of the memory layout. Useful for debugging.
// Slow.
//
// // char[5], 3 bytes of padding, int[3], 4 bytes of padding, followed
// // by an unknown number of doubles.
// auto x = Layout<char, int, double>::Partial(5, 3);
// assert(x.DebugString() ==
// "@0<char>(1)[5]; @8<int>(4)[3]; @24<double>(8)");
//
// Each field is in the following format: @offset<type>(sizeof)[size] (<type>
// may be missing depending on the target platform). For example,
// @8<int>(4)[3] means that at offset 8 we have an array of ints, where each
// int is 4 bytes, and we have 3 of those ints. The size of the last field may
// be missing (as in the example above). Only fields with known offsets are
// described. Type names may differ across platforms: one compiler might
// produce "unsigned*" where another produces "unsigned int *".
std::string DebugString() const {
const auto offsets = Offsets();
const size_t sizes[] = {SizeOf<ElementType<OffsetSeq>>()...};
const std::string types[] = {
adl_barrier::TypeName<ElementType<OffsetSeq>>()...};
std::string res = absl::StrCat("@0", types[0], "(", sizes[0], ")");
for (size_t i = 0; i != NumOffsets - 1; ++i) {
absl::StrAppend(&res, "[", size_[i], "]; @", offsets[i + 1], types[i + 1],
"(", sizes[i + 1], ")");
}
// NumSizes is a constant that may be zero. Some compilers cannot see that
// inside the if statement "size_[NumSizes - 1]" must be valid.
int last = static_cast<int>(NumSizes) - 1;
if (NumTypes == NumSizes && last >= 0) {
absl::StrAppend(&res, "[", size_[last], "]");
}
return res;
}
private:
// Arguments of `Layout::Partial()` or `Layout::Layout()`.
size_t size_[NumSizes > 0 ? NumSizes : 1];
};
template <size_t NumSizes, class... Ts>
using LayoutType = LayoutImpl<
std::tuple<Ts...>, absl::make_index_sequence<NumSizes>,
absl::make_index_sequence<adl_barrier::Min(sizeof...(Ts), NumSizes + 1)>>;
} // namespace internal_layout
// Descriptor of arrays of various types and sizes laid out in memory one after
// another. See the top of the file for documentation.
//
// Check out the public API of internal_layout::LayoutImpl above. The type is
// internal to the library but its methods are public, and they are inherited
// by `Layout`.
template <class... Ts>
class Layout : public internal_layout::LayoutType<sizeof...(Ts), Ts...> {
public:
static_assert(sizeof...(Ts) > 0, "At least one field is required");
static_assert(
absl::conjunction<internal_layout::IsLegalElementType<Ts>...>::value,
"Invalid element type (see IsLegalElementType)");
// The result type of `Partial()` with `NumSizes` arguments.
template <size_t NumSizes>
using PartialType = internal_layout::LayoutType<NumSizes, Ts...>;
// `Layout` knows the element types of the arrays we want to lay out in
// memory but not the number of elements in each array.
// `Partial(size1, ..., sizeN)` allows us to specify the latter. The
// resulting immutable object can be used to obtain pointers to the
// individual arrays.
//
// It's allowed to pass fewer array sizes than the number of arrays. E.g.,
// if all you need is to the offset of the second array, you only need to
Export of internal Abseil changes. -- 15d7bcf28220750db46930f4d8c090b54e3ae5fe by Jon Cohen <cohenjon@google.com>: Fix miscellaneous CMake change interleaving issues for the daily release: * add back the absl::container target * Add copts to absl_cc_library targets in absl/container/CMakeLists.txt * Add trailing newline to the end of AbseilConfigureCopts.cmake PiperOrigin-RevId: 223057096 -- baac35470d75b6561477f688dc4eb021f604cf71 by Abseil Team <absl-team@google.com>: Internal Cleanup. PiperOrigin-RevId: 223051579 -- 6791c2f2e35b030b5579f36d3c607c6ba92fa089 by Abseil Team <absl-team@google.com>: Internal Change. PiperOrigin-RevId: 223046855 -- 5467ad987ea82aef77d2f1cc85aa9105e7d9c320 by Samuel Benzaquen <sbenza@google.com>: Workaround for gcc bug https://gcc.gnu.org/PR88115 PiperOrigin-RevId: 223041901 -- 36fa5cfd41df2b71d26487c45363901bbf6a2463 by Tom Manshreck <shreck@google.com>: Clarify visit() constraints PiperOrigin-RevId: 223032194 -- afdf4013de036b411db7f92cde8a2493e6665223 by Abseil Team <absl-team@google.com>: Fix comment typos. PiperOrigin-RevId: 223024090 -- e11c01927eb8b898f6633282824022104b258342 by Jon Cohen <cohenjon@google.com>: Make absl::spinlock_test_common TESTONLY This should fix https://github.com/abseil/abseil-cpp/issues/221 PiperOrigin-RevId: 222885323 -- 5ccc576d1c68e4b92705aa8064f1e8d715e5415e by Abseil Team <absl-team@google.com>: Internal change. PiperOrigin-RevId: 222877017 -- 96ff25bf78c4f4bca0d6e61faa4feeab91a2e73c by Jon Cohen <cohenjon@google.com>: Align CMake and Bazel compile options. This is the first step towards a single source of truth for Abseil compile options. Also makes absl_test and absl_cc_test make binaries and targets with compatible names to each other to make testing easier. PiperOrigin-RevId: 222858408 -- 7dd3e2618ad5a5de5d918fc73e438ef0b98cec6a by Abseil Team <absl-team@google.com>: Revert "absl: cap SpinLock backoff to 4ms" PiperOrigin-RevId: 222656230 -- 0d49538a3cab714156ed0a5651656c0aa098a1e5 by Abseil Team <absl-team@google.com>: Update absl/container/CMakeLists.txt to use new functions i.e. absl_cc_(library|test) PiperOrigin-RevId: 222535766 -- 92744e9d0e5c3bf9e1167a7bdf1a6777192531b1 by Abseil Team <absl-team@google.com>: Disable header parsing for broken targets PiperOrigin-RevId: 222257218 -- 39a6c623601c44e02d91e412f126a813d719507b by Abseil Team <absl-team@google.com>: absl: cap SpinLock backoff to 4ms The current backoff logic has 3 problems: 1. It can produce too high values (up to 256ms), which can negatively affect tail latency. The value was chosen long time ago and now it's a good idea to reconsider it. 2. It does not have low bound, so on any iteration it can produce a very small value that will lead to unnecessary cpu consumption. 3. It does not increase low bound with the number of iterations. So if the SpinLock is actually somehow locked for a very prolonged time, a waiter can still wake periodically. Rework the logic to solve these problems. Add lower bound of 128us, no code should rely on absence of episodic delays in this range as they can occur everywhere. Lower upper bound to 4ms. A thread sleeping for 4ms does not consume significant cpu time (see below). Grow lower bound with the number of iterations. This is cpu consumption of a process doing usleep(x) in a loop (sampled with ps): 64us -> 4.0% 128us -> 2.7% 256us -> 3.5% 512us -> 2.8% 1024us -> 1.6% 2048us -> 0.6% 4096us -> 0.3% 8192us -> 0.0% Few millisecond sleeps do not consume significant time. PiperOrigin-RevId: 222196086 -- 17104a2396ddda61fb0faed0a72ff8c161ca17ea by Shahriar Rouf <nafi@google.com>: Add benchmarks for hashing civil_times. PiperOrigin-RevId: 222152108 GitOrigin-RevId: 15d7bcf28220750db46930f4d8c090b54e3ae5fe Change-Id: I73b929feaf6ce72b70fdafd6108f53bbbeaf9738
6 years ago
// pass one argument -- the number of elements in the first array.
//
// // int[3] followed by 4 bytes of padding and an unknown number of
// // doubles.
// auto x = Layout<int, double>::Partial(3);
// // doubles start at byte 16.
// assert(x.Offset<1>() == 16);
//
// If you know the number of elements in all arrays, you can still call
// `Partial()` but it's more convenient to use the constructor of `Layout`.
//
// Layout<int, double> x(3, 5);
//
// Note: The sizes of the arrays must be specified in number of elements,
// not in bytes.
//
// Requires: `sizeof...(Sizes) <= sizeof...(Ts)`.
// Requires: all arguments are convertible to `size_t`.
template <class... Sizes>
static constexpr PartialType<sizeof...(Sizes)> Partial(Sizes&&... sizes) {
static_assert(sizeof...(Sizes) <= sizeof...(Ts), "");
return PartialType<sizeof...(Sizes)>(absl::forward<Sizes>(sizes)...);
}
// Creates a layout with the sizes of all arrays specified. If you know
// only the sizes of the first N arrays (where N can be zero), you can use
// `Partial()` defined above. The constructor is essentially equivalent to
// calling `Partial()` and passing in all array sizes; the constructor is
// provided as a convenient abbreviation.
//
// Note: The sizes of the arrays must be specified in number of elements,
// not in bytes.
constexpr explicit Layout(internal_layout::TypeToSize<Ts>... sizes)
: internal_layout::LayoutType<sizeof...(Ts), Ts...>(sizes...) {}
};
} // namespace container_internal
Export of internal Abseil changes -- c99f979ad34f155fbeeea69b88bdc7458d89a21c by Derek Mauro <dmauro@google.com>: Remove a floating point division by zero test. This isn't testing behavior related to the library, and MSVC warns about it in opt mode. PiperOrigin-RevId: 285220804 -- 68b015491f0dbf1ab547994673281abd1f34cd4b by Gennadiy Rozental <rogeeff@google.com>: This CL introduces following changes to the class FlagImpl: * We eliminate the CommandLineFlagLocks struct. Instead callback guard and callback function are combined into a single CallbackData struct, while primary data lock is stored separately. * CallbackData member of class FlagImpl is initially set to be nullptr and is only allocated and initialized when a flag's callback is being set. For most flags we do not pay for the extra space and extra absl::Mutex now. * Primary data guard is stored in data_guard_ data member. This is a properly aligned character buffer of necessary size. During initialization of the flag we construct absl::Mutex in this space using placement new call. * We now avoid extra value copy after successful attempt to parse value out of string. Instead we swap flag's current value with tentative value we just produced. PiperOrigin-RevId: 285132636 -- ed45d118fb818969eb13094cf7827c885dfc562c by Tom Manshreck <shreck@google.com>: Change null-term* (and nul-term*) to NUL-term* in comments PiperOrigin-RevId: 285036610 -- 729619017944db895ce8d6d29c1995aa2e5628a5 by Derek Mauro <dmauro@google.com>: Use the Posix implementation of thread identity on MinGW. Some versions of MinGW suffer from thread_local bugs. PiperOrigin-RevId: 285022920 -- 39a25493503c76885bc3254c28f66a251c5b5bb0 by Greg Falcon <gfalcon@google.com>: Implementation detail change. Add further ABSL_NAMESPACE_BEGIN and _END annotation macros to files in Abseil. PiperOrigin-RevId: 285012012 GitOrigin-RevId: c99f979ad34f155fbeeea69b88bdc7458d89a21c Change-Id: I4c85d3704e45d11a9ac50d562f39640a6adbedc1
5 years ago
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_CONTAINER_INTERNAL_LAYOUT_H_