Abseil Common Libraries (C++) (grcp 依赖) https://abseil.io/
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Export of internal Abseil changes. -- 7fa1107161a03dac53fb84c2b06d8092616c7b13 by Abseil Team <absl-team@google.com>: Harden the generic stacktrace implementation for use during early program execution PiperOrigin-RevId: 226375950 -- 079f9969329f5eb66f647dd3c44b17541b1bf217 by Matt Kulukundis <kfm@google.com>: Workaround platforms that have over-aggressive warnings on -Wexit-time-destructors PiperOrigin-RevId: 226362948 -- 1447943f509be681ca5495add0162c750ef237f1 by Matt Kulukundis <kfm@google.com>: Switch from 64 to size_t atomics so they work on embedded platforms that do not have 64 bit atomics. PiperOrigin-RevId: 226210704 -- d14d49837ae2bcde74051e0c79c18ee0f43866b9 by Tom Manshreck <shreck@google.com>: Develop initial documentation for API breaking changes process: PiperOrigin-RevId: 226210021 -- 7ea3d7fe0e86979dab83a5fc9cc3bf1d6cb3bd53 by Abseil Team <absl-team@google.com>: Import of CCTZ from GitHub. PiperOrigin-RevId: 226195522 -- 7de873e880d7f016a4fa1e08d626f0535cc470af by Abseil Team <absl-team@google.com>: Make Abseil LICENSE files newline terminated, with a single trailing blank line. Also remove line-ending whitespace. PiperOrigin-RevId: 226182949 -- 7d00643fadfad7f0d992c68bd9d2ed2e5bc960b0 by Matt Kulukundis <kfm@google.com>: Internal cleanup PiperOrigin-RevId: 226045282 -- c4a0a11c0ce2875271191e477f3d36eaaeca4613 by Matt Kulukundis <kfm@google.com>: Internal cleanup PiperOrigin-RevId: 226038273 -- 8ee4ebbb1ae5cda119e436e5ff7e3aa966608c10 by Matt Kulukundis <kfm@google.com>: Adds a global sampler which tracks a fraction of live tables for collecting telemetry data. PiperOrigin-RevId: 226032080 -- d576446f050518cd1b0ae447d682d8552f0e7e30 by Mark Barolak <mbar@google.com>: Replace an internal CaseEqual function with calls to the identical absl::EqualsIgnoreCase. This closes out a rather old TODO. PiperOrigin-RevId: 226024779 -- 6b23f1ee028a5ffa608c920424f1220a117a8f3d by Abseil Team <absl-team@google.com>: Add December 2018 LTS branch to list of LTS branches. PiperOrigin-RevId: 226011333 -- bb0833a43bdaef4c8c059b17bcd27ba9a085a114 by Mark Barolak <mbar@google.com>: Explicitly state that when the SimpleAtoi family of functions encounter an error, the value of their output parameter is unspecified. Also standardize the name of the output parameter to be `out`. PiperOrigin-RevId: 225997035 -- 46c1876b1a248eabda7545daa61a74a4cdfe9077 by Abseil Team <absl-team@google.com>: Remove deprecated CMake function absl_test, absl_library and absl_header_library PiperOrigin-RevId: 225950041 GitOrigin-RevId: 7fa1107161a03dac53fb84c2b06d8092616c7b13 Change-Id: I2ca9d3aada9292614527d1339a7557494139b806
6 years ago
// 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
//
// http://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.
//
// This is a low level library to sample hashtables and collect runtime
// statistics about them.
//
// `HashtablezSampler` controls the lifecycle of `HashtablezInfo` objects which
// store information about a single sample.
//
// `Record*` methods store information into samples.
// `Sample()` and `Unsample()` make use of a single global sampler with
// properties controlled by the flags hashtablez_enabled,
// hashtablez_sample_rate, and hashtablez_max_samples.
#ifndef ABSL_CONTAINER_INTERNAL_HASHTABLEZ_SAMPLER_H_
#define ABSL_CONTAINER_INTERNAL_HASHTABLEZ_SAMPLER_H_
#include <atomic>
#include <functional>
#include <memory>
#include <vector>
Export of internal Abseil changes. -- 5f1cf6547231f1b1daad6d1b785df6b0b999b3c9 by Samuel Benzaquen <sbenza@google.com>: Fix uninitialized member in the `iterator` class by using a union of the two possible states of the iterator. This silences a Wuninitialized warning in gcc>=7. PiperOrigin-RevId: 228175148 -- 98b4e3204c0ec3cfd4cb037e24d443ea4b63fc84 by CJ Johnson <johnsoncj@google.com>: Factors out the implementation of InlinedVector::swap(...) into a private member function PiperOrigin-RevId: 228173383 -- f1432ad3a8b05285c6d55bc4754cfae765485b7f by Abseil Team <absl-team@google.com>: Import of CCTZ from GitHub. PiperOrigin-RevId: 227891984 -- 03fc00c7a4efc6000e6d9125cb2e252bffda76fe by Andy Getzendanner <durandal@google.com>: Add a missing linebreak to a comment and markdownify two unordered lists. PiperOrigin-RevId: 227861389 -- 0d66c9afba4fc9aa52e61d9fb410e165018a7b48 by Abseil Team <absl-team@google.com>: Add an API to register a new source for the cycle clock. PiperOrigin-RevId: 227779218 -- 14d3f9b70c8818b8541e5fb2f6ca4c59d479de31 by Andy Getzendanner <durandal@google.com>: Correct a typo in a stripping marker. PiperOrigin-RevId: 227750014 -- 59df88740f4e315beb57a8772f8bcf7879440c74 by Matt Kulukundis <kfm@google.com>: Switch thread local handling to be more cross platform PiperOrigin-RevId: 227695133 -- 75deed5bfcb5c42534e933f104aa7d94e11e348d by Abseil Team <absl-team@google.com>: Rollback workaround toolchain bug for incorrect handling of thread_local in inline functions PiperOrigin-RevId: 227689133 -- 54994bf0afec026e6e0e7a199df0bbb4b7d9a4aa by Derek Mauro <dmauro@google.com>: Add -pthread to linkopts where it actually belongs, on the library that uses it. Fixes https://github.com/abseil/abseil-cpp/issues/240. PiperOrigin-RevId: 227612492 -- 893875f3536b7e0a1bad993aa6b2e083abb3b25a by Derek Mauro <dmauro@google.com>: Internal change PiperOrigin-RevId: 227582833 -- 506c9b8e9002ca3389c7040473b68d4cbf94bdcc by Matt Kulukundis <kfm@google.com>: Workaround toolchain bug for incorrect handling of thread_local in inline functions PiperOrigin-RevId: 227561449 -- 29ee90d96dfe3114cf93f9bb92ea0cc9e768a407 by Derek Mauro <dmauro@google.com>: Internal change PiperOrigin-RevId: 227054634 GitOrigin-RevId: 5f1cf6547231f1b1daad6d1b785df6b0b999b3c9 Change-Id: Ibc90566d92ee6e0ad7e150f513ec7f5d22ec0a94
6 years ago
#include "absl/base/internal/per_thread_tls.h"
Export of internal Abseil changes. -- 7fa1107161a03dac53fb84c2b06d8092616c7b13 by Abseil Team <absl-team@google.com>: Harden the generic stacktrace implementation for use during early program execution PiperOrigin-RevId: 226375950 -- 079f9969329f5eb66f647dd3c44b17541b1bf217 by Matt Kulukundis <kfm@google.com>: Workaround platforms that have over-aggressive warnings on -Wexit-time-destructors PiperOrigin-RevId: 226362948 -- 1447943f509be681ca5495add0162c750ef237f1 by Matt Kulukundis <kfm@google.com>: Switch from 64 to size_t atomics so they work on embedded platforms that do not have 64 bit atomics. PiperOrigin-RevId: 226210704 -- d14d49837ae2bcde74051e0c79c18ee0f43866b9 by Tom Manshreck <shreck@google.com>: Develop initial documentation for API breaking changes process: PiperOrigin-RevId: 226210021 -- 7ea3d7fe0e86979dab83a5fc9cc3bf1d6cb3bd53 by Abseil Team <absl-team@google.com>: Import of CCTZ from GitHub. PiperOrigin-RevId: 226195522 -- 7de873e880d7f016a4fa1e08d626f0535cc470af by Abseil Team <absl-team@google.com>: Make Abseil LICENSE files newline terminated, with a single trailing blank line. Also remove line-ending whitespace. PiperOrigin-RevId: 226182949 -- 7d00643fadfad7f0d992c68bd9d2ed2e5bc960b0 by Matt Kulukundis <kfm@google.com>: Internal cleanup PiperOrigin-RevId: 226045282 -- c4a0a11c0ce2875271191e477f3d36eaaeca4613 by Matt Kulukundis <kfm@google.com>: Internal cleanup PiperOrigin-RevId: 226038273 -- 8ee4ebbb1ae5cda119e436e5ff7e3aa966608c10 by Matt Kulukundis <kfm@google.com>: Adds a global sampler which tracks a fraction of live tables for collecting telemetry data. PiperOrigin-RevId: 226032080 -- d576446f050518cd1b0ae447d682d8552f0e7e30 by Mark Barolak <mbar@google.com>: Replace an internal CaseEqual function with calls to the identical absl::EqualsIgnoreCase. This closes out a rather old TODO. PiperOrigin-RevId: 226024779 -- 6b23f1ee028a5ffa608c920424f1220a117a8f3d by Abseil Team <absl-team@google.com>: Add December 2018 LTS branch to list of LTS branches. PiperOrigin-RevId: 226011333 -- bb0833a43bdaef4c8c059b17bcd27ba9a085a114 by Mark Barolak <mbar@google.com>: Explicitly state that when the SimpleAtoi family of functions encounter an error, the value of their output parameter is unspecified. Also standardize the name of the output parameter to be `out`. PiperOrigin-RevId: 225997035 -- 46c1876b1a248eabda7545daa61a74a4cdfe9077 by Abseil Team <absl-team@google.com>: Remove deprecated CMake function absl_test, absl_library and absl_header_library PiperOrigin-RevId: 225950041 GitOrigin-RevId: 7fa1107161a03dac53fb84c2b06d8092616c7b13 Change-Id: I2ca9d3aada9292614527d1339a7557494139b806
6 years ago
#include "absl/base/optimization.h"
#include "absl/synchronization/mutex.h"
#include "absl/utility/utility.h"
namespace absl {
namespace container_internal {
// Stores information about a sampled hashtable. All mutations to this *must*
// be made through `Record*` functions below. All reads from this *must* only
// occur in the callback to `HashtablezSampler::Iterate`.
struct HashtablezInfo {
// Constructs the object but does not fill in any fields.
HashtablezInfo();
~HashtablezInfo();
HashtablezInfo(const HashtablezInfo&) = delete;
HashtablezInfo& operator=(const HashtablezInfo&) = delete;
// Puts the object into a clean state, fills in the logically `const` members,
// blocking for any readers that are currently sampling the object.
void PrepareForSampling() EXCLUSIVE_LOCKS_REQUIRED(init_mu);
// These fields are mutated by the various Record* APIs and need to be
// thread-safe.
std::atomic<size_t> capacity;
std::atomic<size_t> size;
std::atomic<size_t> num_erases;
std::atomic<size_t> max_probe_length;
std::atomic<size_t> total_probe_length;
std::atomic<size_t> hashes_bitwise_or;
std::atomic<size_t> hashes_bitwise_and;
// `HashtablezSampler` maintains intrusive linked lists for all samples. See
// comments on `HashtablezSampler::all_` for details on these. `init_mu`
// guards the ability to restore the sample to a pristine state. This
// prevents races with sampling and resurrecting an object.
absl::Mutex init_mu;
HashtablezInfo* next;
HashtablezInfo* dead GUARDED_BY(init_mu);
// All of the fields below are set by `PrepareForSampling`, they must not be
// mutated in `Record*` functions. They are logically `const` in that sense.
// These are guarded by init_mu, but that is not externalized to clients, who
// can only read them during `HashtablezSampler::Iterate` which will hold the
// lock.
static constexpr int kMaxStackDepth = 64;
absl::Time create_time;
int32_t depth;
void* stack[kMaxStackDepth];
};
inline void RecordStorageChangedSlow(HashtablezInfo* info, size_t size,
size_t capacity) {
info->size.store(size, std::memory_order_relaxed);
info->capacity.store(capacity, std::memory_order_relaxed);
}
void RecordInsertSlow(HashtablezInfo* info, size_t hash,
size_t distance_from_desired);
inline void RecordEraseSlow(HashtablezInfo* info) {
info->size.fetch_sub(1, std::memory_order_relaxed);
info->num_erases.fetch_add(1, std::memory_order_relaxed);
}
HashtablezInfo* SampleSlow(int64_t* next_sample);
void UnsampleSlow(HashtablezInfo* info);
class HashtablezInfoHandle {
public:
explicit HashtablezInfoHandle() : info_(nullptr) {}
explicit HashtablezInfoHandle(HashtablezInfo* info) : info_(info) {}
~HashtablezInfoHandle() {
if (ABSL_PREDICT_TRUE(info_ == nullptr)) return;
UnsampleSlow(info_);
}
HashtablezInfoHandle(const HashtablezInfoHandle&) = delete;
HashtablezInfoHandle& operator=(const HashtablezInfoHandle&) = delete;
HashtablezInfoHandle(HashtablezInfoHandle&& o) noexcept
: info_(absl::exchange(o.info_, nullptr)) {}
HashtablezInfoHandle& operator=(HashtablezInfoHandle&& o) noexcept {
if (ABSL_PREDICT_FALSE(info_ != nullptr)) {
UnsampleSlow(info_);
}
info_ = absl::exchange(o.info_, nullptr);
return *this;
}
inline void RecordStorageChanged(size_t size, size_t capacity) {
if (ABSL_PREDICT_TRUE(info_ == nullptr)) return;
RecordStorageChangedSlow(info_, size, capacity);
}
inline void RecordInsert(size_t hash, size_t distance_from_desired) {
if (ABSL_PREDICT_TRUE(info_ == nullptr)) return;
RecordInsertSlow(info_, hash, distance_from_desired);
}
inline void RecordErase() {
if (ABSL_PREDICT_TRUE(info_ == nullptr)) return;
RecordEraseSlow(info_);
}
friend inline void swap(HashtablezInfoHandle& lhs,
HashtablezInfoHandle& rhs) {
std::swap(lhs.info_, rhs.info_);
}
private:
friend class HashtablezInfoHandlePeer;
HashtablezInfo* info_;
};
// Returns an RAII sampling handle that manages registration and unregistation
// with the global sampler.
Export of internal Abseil changes. -- 5f1cf6547231f1b1daad6d1b785df6b0b999b3c9 by Samuel Benzaquen <sbenza@google.com>: Fix uninitialized member in the `iterator` class by using a union of the two possible states of the iterator. This silences a Wuninitialized warning in gcc>=7. PiperOrigin-RevId: 228175148 -- 98b4e3204c0ec3cfd4cb037e24d443ea4b63fc84 by CJ Johnson <johnsoncj@google.com>: Factors out the implementation of InlinedVector::swap(...) into a private member function PiperOrigin-RevId: 228173383 -- f1432ad3a8b05285c6d55bc4754cfae765485b7f by Abseil Team <absl-team@google.com>: Import of CCTZ from GitHub. PiperOrigin-RevId: 227891984 -- 03fc00c7a4efc6000e6d9125cb2e252bffda76fe by Andy Getzendanner <durandal@google.com>: Add a missing linebreak to a comment and markdownify two unordered lists. PiperOrigin-RevId: 227861389 -- 0d66c9afba4fc9aa52e61d9fb410e165018a7b48 by Abseil Team <absl-team@google.com>: Add an API to register a new source for the cycle clock. PiperOrigin-RevId: 227779218 -- 14d3f9b70c8818b8541e5fb2f6ca4c59d479de31 by Andy Getzendanner <durandal@google.com>: Correct a typo in a stripping marker. PiperOrigin-RevId: 227750014 -- 59df88740f4e315beb57a8772f8bcf7879440c74 by Matt Kulukundis <kfm@google.com>: Switch thread local handling to be more cross platform PiperOrigin-RevId: 227695133 -- 75deed5bfcb5c42534e933f104aa7d94e11e348d by Abseil Team <absl-team@google.com>: Rollback workaround toolchain bug for incorrect handling of thread_local in inline functions PiperOrigin-RevId: 227689133 -- 54994bf0afec026e6e0e7a199df0bbb4b7d9a4aa by Derek Mauro <dmauro@google.com>: Add -pthread to linkopts where it actually belongs, on the library that uses it. Fixes https://github.com/abseil/abseil-cpp/issues/240. PiperOrigin-RevId: 227612492 -- 893875f3536b7e0a1bad993aa6b2e083abb3b25a by Derek Mauro <dmauro@google.com>: Internal change PiperOrigin-RevId: 227582833 -- 506c9b8e9002ca3389c7040473b68d4cbf94bdcc by Matt Kulukundis <kfm@google.com>: Workaround toolchain bug for incorrect handling of thread_local in inline functions PiperOrigin-RevId: 227561449 -- 29ee90d96dfe3114cf93f9bb92ea0cc9e768a407 by Derek Mauro <dmauro@google.com>: Internal change PiperOrigin-RevId: 227054634 GitOrigin-RevId: 5f1cf6547231f1b1daad6d1b785df6b0b999b3c9 Change-Id: Ibc90566d92ee6e0ad7e150f513ec7f5d22ec0a94
6 years ago
#if ABSL_PER_THREAD_TLS == 1
extern ABSL_PER_THREAD_TLS_KEYWORD int64_t next_sample;
#endif // ABSL_PER_THREAD_TLS
Export of internal Abseil changes. -- 7fa1107161a03dac53fb84c2b06d8092616c7b13 by Abseil Team <absl-team@google.com>: Harden the generic stacktrace implementation for use during early program execution PiperOrigin-RevId: 226375950 -- 079f9969329f5eb66f647dd3c44b17541b1bf217 by Matt Kulukundis <kfm@google.com>: Workaround platforms that have over-aggressive warnings on -Wexit-time-destructors PiperOrigin-RevId: 226362948 -- 1447943f509be681ca5495add0162c750ef237f1 by Matt Kulukundis <kfm@google.com>: Switch from 64 to size_t atomics so they work on embedded platforms that do not have 64 bit atomics. PiperOrigin-RevId: 226210704 -- d14d49837ae2bcde74051e0c79c18ee0f43866b9 by Tom Manshreck <shreck@google.com>: Develop initial documentation for API breaking changes process: PiperOrigin-RevId: 226210021 -- 7ea3d7fe0e86979dab83a5fc9cc3bf1d6cb3bd53 by Abseil Team <absl-team@google.com>: Import of CCTZ from GitHub. PiperOrigin-RevId: 226195522 -- 7de873e880d7f016a4fa1e08d626f0535cc470af by Abseil Team <absl-team@google.com>: Make Abseil LICENSE files newline terminated, with a single trailing blank line. Also remove line-ending whitespace. PiperOrigin-RevId: 226182949 -- 7d00643fadfad7f0d992c68bd9d2ed2e5bc960b0 by Matt Kulukundis <kfm@google.com>: Internal cleanup PiperOrigin-RevId: 226045282 -- c4a0a11c0ce2875271191e477f3d36eaaeca4613 by Matt Kulukundis <kfm@google.com>: Internal cleanup PiperOrigin-RevId: 226038273 -- 8ee4ebbb1ae5cda119e436e5ff7e3aa966608c10 by Matt Kulukundis <kfm@google.com>: Adds a global sampler which tracks a fraction of live tables for collecting telemetry data. PiperOrigin-RevId: 226032080 -- d576446f050518cd1b0ae447d682d8552f0e7e30 by Mark Barolak <mbar@google.com>: Replace an internal CaseEqual function with calls to the identical absl::EqualsIgnoreCase. This closes out a rather old TODO. PiperOrigin-RevId: 226024779 -- 6b23f1ee028a5ffa608c920424f1220a117a8f3d by Abseil Team <absl-team@google.com>: Add December 2018 LTS branch to list of LTS branches. PiperOrigin-RevId: 226011333 -- bb0833a43bdaef4c8c059b17bcd27ba9a085a114 by Mark Barolak <mbar@google.com>: Explicitly state that when the SimpleAtoi family of functions encounter an error, the value of their output parameter is unspecified. Also standardize the name of the output parameter to be `out`. PiperOrigin-RevId: 225997035 -- 46c1876b1a248eabda7545daa61a74a4cdfe9077 by Abseil Team <absl-team@google.com>: Remove deprecated CMake function absl_test, absl_library and absl_header_library PiperOrigin-RevId: 225950041 GitOrigin-RevId: 7fa1107161a03dac53fb84c2b06d8092616c7b13 Change-Id: I2ca9d3aada9292614527d1339a7557494139b806
6 years ago
inline HashtablezInfoHandle Sample() {
Export of internal Abseil changes. -- 5f1cf6547231f1b1daad6d1b785df6b0b999b3c9 by Samuel Benzaquen <sbenza@google.com>: Fix uninitialized member in the `iterator` class by using a union of the two possible states of the iterator. This silences a Wuninitialized warning in gcc>=7. PiperOrigin-RevId: 228175148 -- 98b4e3204c0ec3cfd4cb037e24d443ea4b63fc84 by CJ Johnson <johnsoncj@google.com>: Factors out the implementation of InlinedVector::swap(...) into a private member function PiperOrigin-RevId: 228173383 -- f1432ad3a8b05285c6d55bc4754cfae765485b7f by Abseil Team <absl-team@google.com>: Import of CCTZ from GitHub. PiperOrigin-RevId: 227891984 -- 03fc00c7a4efc6000e6d9125cb2e252bffda76fe by Andy Getzendanner <durandal@google.com>: Add a missing linebreak to a comment and markdownify two unordered lists. PiperOrigin-RevId: 227861389 -- 0d66c9afba4fc9aa52e61d9fb410e165018a7b48 by Abseil Team <absl-team@google.com>: Add an API to register a new source for the cycle clock. PiperOrigin-RevId: 227779218 -- 14d3f9b70c8818b8541e5fb2f6ca4c59d479de31 by Andy Getzendanner <durandal@google.com>: Correct a typo in a stripping marker. PiperOrigin-RevId: 227750014 -- 59df88740f4e315beb57a8772f8bcf7879440c74 by Matt Kulukundis <kfm@google.com>: Switch thread local handling to be more cross platform PiperOrigin-RevId: 227695133 -- 75deed5bfcb5c42534e933f104aa7d94e11e348d by Abseil Team <absl-team@google.com>: Rollback workaround toolchain bug for incorrect handling of thread_local in inline functions PiperOrigin-RevId: 227689133 -- 54994bf0afec026e6e0e7a199df0bbb4b7d9a4aa by Derek Mauro <dmauro@google.com>: Add -pthread to linkopts where it actually belongs, on the library that uses it. Fixes https://github.com/abseil/abseil-cpp/issues/240. PiperOrigin-RevId: 227612492 -- 893875f3536b7e0a1bad993aa6b2e083abb3b25a by Derek Mauro <dmauro@google.com>: Internal change PiperOrigin-RevId: 227582833 -- 506c9b8e9002ca3389c7040473b68d4cbf94bdcc by Matt Kulukundis <kfm@google.com>: Workaround toolchain bug for incorrect handling of thread_local in inline functions PiperOrigin-RevId: 227561449 -- 29ee90d96dfe3114cf93f9bb92ea0cc9e768a407 by Derek Mauro <dmauro@google.com>: Internal change PiperOrigin-RevId: 227054634 GitOrigin-RevId: 5f1cf6547231f1b1daad6d1b785df6b0b999b3c9 Change-Id: Ibc90566d92ee6e0ad7e150f513ec7f5d22ec0a94
6 years ago
#if ABSL_PER_THREAD_TLS == 0
Export of internal Abseil changes. -- 7fa1107161a03dac53fb84c2b06d8092616c7b13 by Abseil Team <absl-team@google.com>: Harden the generic stacktrace implementation for use during early program execution PiperOrigin-RevId: 226375950 -- 079f9969329f5eb66f647dd3c44b17541b1bf217 by Matt Kulukundis <kfm@google.com>: Workaround platforms that have over-aggressive warnings on -Wexit-time-destructors PiperOrigin-RevId: 226362948 -- 1447943f509be681ca5495add0162c750ef237f1 by Matt Kulukundis <kfm@google.com>: Switch from 64 to size_t atomics so they work on embedded platforms that do not have 64 bit atomics. PiperOrigin-RevId: 226210704 -- d14d49837ae2bcde74051e0c79c18ee0f43866b9 by Tom Manshreck <shreck@google.com>: Develop initial documentation for API breaking changes process: PiperOrigin-RevId: 226210021 -- 7ea3d7fe0e86979dab83a5fc9cc3bf1d6cb3bd53 by Abseil Team <absl-team@google.com>: Import of CCTZ from GitHub. PiperOrigin-RevId: 226195522 -- 7de873e880d7f016a4fa1e08d626f0535cc470af by Abseil Team <absl-team@google.com>: Make Abseil LICENSE files newline terminated, with a single trailing blank line. Also remove line-ending whitespace. PiperOrigin-RevId: 226182949 -- 7d00643fadfad7f0d992c68bd9d2ed2e5bc960b0 by Matt Kulukundis <kfm@google.com>: Internal cleanup PiperOrigin-RevId: 226045282 -- c4a0a11c0ce2875271191e477f3d36eaaeca4613 by Matt Kulukundis <kfm@google.com>: Internal cleanup PiperOrigin-RevId: 226038273 -- 8ee4ebbb1ae5cda119e436e5ff7e3aa966608c10 by Matt Kulukundis <kfm@google.com>: Adds a global sampler which tracks a fraction of live tables for collecting telemetry data. PiperOrigin-RevId: 226032080 -- d576446f050518cd1b0ae447d682d8552f0e7e30 by Mark Barolak <mbar@google.com>: Replace an internal CaseEqual function with calls to the identical absl::EqualsIgnoreCase. This closes out a rather old TODO. PiperOrigin-RevId: 226024779 -- 6b23f1ee028a5ffa608c920424f1220a117a8f3d by Abseil Team <absl-team@google.com>: Add December 2018 LTS branch to list of LTS branches. PiperOrigin-RevId: 226011333 -- bb0833a43bdaef4c8c059b17bcd27ba9a085a114 by Mark Barolak <mbar@google.com>: Explicitly state that when the SimpleAtoi family of functions encounter an error, the value of their output parameter is unspecified. Also standardize the name of the output parameter to be `out`. PiperOrigin-RevId: 225997035 -- 46c1876b1a248eabda7545daa61a74a4cdfe9077 by Abseil Team <absl-team@google.com>: Remove deprecated CMake function absl_test, absl_library and absl_header_library PiperOrigin-RevId: 225950041 GitOrigin-RevId: 7fa1107161a03dac53fb84c2b06d8092616c7b13 Change-Id: I2ca9d3aada9292614527d1339a7557494139b806
6 years ago
static auto* mu = new absl::Mutex;
static int64_t next_sample = 0;
absl::MutexLock l(mu);
Export of internal Abseil changes. -- 5f1cf6547231f1b1daad6d1b785df6b0b999b3c9 by Samuel Benzaquen <sbenza@google.com>: Fix uninitialized member in the `iterator` class by using a union of the two possible states of the iterator. This silences a Wuninitialized warning in gcc>=7. PiperOrigin-RevId: 228175148 -- 98b4e3204c0ec3cfd4cb037e24d443ea4b63fc84 by CJ Johnson <johnsoncj@google.com>: Factors out the implementation of InlinedVector::swap(...) into a private member function PiperOrigin-RevId: 228173383 -- f1432ad3a8b05285c6d55bc4754cfae765485b7f by Abseil Team <absl-team@google.com>: Import of CCTZ from GitHub. PiperOrigin-RevId: 227891984 -- 03fc00c7a4efc6000e6d9125cb2e252bffda76fe by Andy Getzendanner <durandal@google.com>: Add a missing linebreak to a comment and markdownify two unordered lists. PiperOrigin-RevId: 227861389 -- 0d66c9afba4fc9aa52e61d9fb410e165018a7b48 by Abseil Team <absl-team@google.com>: Add an API to register a new source for the cycle clock. PiperOrigin-RevId: 227779218 -- 14d3f9b70c8818b8541e5fb2f6ca4c59d479de31 by Andy Getzendanner <durandal@google.com>: Correct a typo in a stripping marker. PiperOrigin-RevId: 227750014 -- 59df88740f4e315beb57a8772f8bcf7879440c74 by Matt Kulukundis <kfm@google.com>: Switch thread local handling to be more cross platform PiperOrigin-RevId: 227695133 -- 75deed5bfcb5c42534e933f104aa7d94e11e348d by Abseil Team <absl-team@google.com>: Rollback workaround toolchain bug for incorrect handling of thread_local in inline functions PiperOrigin-RevId: 227689133 -- 54994bf0afec026e6e0e7a199df0bbb4b7d9a4aa by Derek Mauro <dmauro@google.com>: Add -pthread to linkopts where it actually belongs, on the library that uses it. Fixes https://github.com/abseil/abseil-cpp/issues/240. PiperOrigin-RevId: 227612492 -- 893875f3536b7e0a1bad993aa6b2e083abb3b25a by Derek Mauro <dmauro@google.com>: Internal change PiperOrigin-RevId: 227582833 -- 506c9b8e9002ca3389c7040473b68d4cbf94bdcc by Matt Kulukundis <kfm@google.com>: Workaround toolchain bug for incorrect handling of thread_local in inline functions PiperOrigin-RevId: 227561449 -- 29ee90d96dfe3114cf93f9bb92ea0cc9e768a407 by Derek Mauro <dmauro@google.com>: Internal change PiperOrigin-RevId: 227054634 GitOrigin-RevId: 5f1cf6547231f1b1daad6d1b785df6b0b999b3c9 Change-Id: Ibc90566d92ee6e0ad7e150f513ec7f5d22ec0a94
6 years ago
#endif // !ABSL_HAVE_THREAD_LOCAL
Export of internal Abseil changes. -- 7fa1107161a03dac53fb84c2b06d8092616c7b13 by Abseil Team <absl-team@google.com>: Harden the generic stacktrace implementation for use during early program execution PiperOrigin-RevId: 226375950 -- 079f9969329f5eb66f647dd3c44b17541b1bf217 by Matt Kulukundis <kfm@google.com>: Workaround platforms that have over-aggressive warnings on -Wexit-time-destructors PiperOrigin-RevId: 226362948 -- 1447943f509be681ca5495add0162c750ef237f1 by Matt Kulukundis <kfm@google.com>: Switch from 64 to size_t atomics so they work on embedded platforms that do not have 64 bit atomics. PiperOrigin-RevId: 226210704 -- d14d49837ae2bcde74051e0c79c18ee0f43866b9 by Tom Manshreck <shreck@google.com>: Develop initial documentation for API breaking changes process: PiperOrigin-RevId: 226210021 -- 7ea3d7fe0e86979dab83a5fc9cc3bf1d6cb3bd53 by Abseil Team <absl-team@google.com>: Import of CCTZ from GitHub. PiperOrigin-RevId: 226195522 -- 7de873e880d7f016a4fa1e08d626f0535cc470af by Abseil Team <absl-team@google.com>: Make Abseil LICENSE files newline terminated, with a single trailing blank line. Also remove line-ending whitespace. PiperOrigin-RevId: 226182949 -- 7d00643fadfad7f0d992c68bd9d2ed2e5bc960b0 by Matt Kulukundis <kfm@google.com>: Internal cleanup PiperOrigin-RevId: 226045282 -- c4a0a11c0ce2875271191e477f3d36eaaeca4613 by Matt Kulukundis <kfm@google.com>: Internal cleanup PiperOrigin-RevId: 226038273 -- 8ee4ebbb1ae5cda119e436e5ff7e3aa966608c10 by Matt Kulukundis <kfm@google.com>: Adds a global sampler which tracks a fraction of live tables for collecting telemetry data. PiperOrigin-RevId: 226032080 -- d576446f050518cd1b0ae447d682d8552f0e7e30 by Mark Barolak <mbar@google.com>: Replace an internal CaseEqual function with calls to the identical absl::EqualsIgnoreCase. This closes out a rather old TODO. PiperOrigin-RevId: 226024779 -- 6b23f1ee028a5ffa608c920424f1220a117a8f3d by Abseil Team <absl-team@google.com>: Add December 2018 LTS branch to list of LTS branches. PiperOrigin-RevId: 226011333 -- bb0833a43bdaef4c8c059b17bcd27ba9a085a114 by Mark Barolak <mbar@google.com>: Explicitly state that when the SimpleAtoi family of functions encounter an error, the value of their output parameter is unspecified. Also standardize the name of the output parameter to be `out`. PiperOrigin-RevId: 225997035 -- 46c1876b1a248eabda7545daa61a74a4cdfe9077 by Abseil Team <absl-team@google.com>: Remove deprecated CMake function absl_test, absl_library and absl_header_library PiperOrigin-RevId: 225950041 GitOrigin-RevId: 7fa1107161a03dac53fb84c2b06d8092616c7b13 Change-Id: I2ca9d3aada9292614527d1339a7557494139b806
6 years ago
if (ABSL_PREDICT_TRUE(--next_sample > 0)) {
return HashtablezInfoHandle(nullptr);
}
return HashtablezInfoHandle(SampleSlow(&next_sample));
}
// Holds samples and their associated stack traces with a soft limit of
// `SetHashtablezMaxSamples()`.
//
// Thread safe.
class HashtablezSampler {
public:
// Returns a global Sampler.
static HashtablezSampler& Global();
HashtablezSampler();
~HashtablezSampler();
// Registers for sampling. Returns an opaque registration info.
HashtablezInfo* Register();
// Unregisters the sample.
void Unregister(HashtablezInfo* sample);
// Iterates over all the registered `StackInfo`s. Returning the number of
// samples that have been dropped.
int64_t Iterate(const std::function<void(const HashtablezInfo& stack)>& f);
private:
void PushNew(HashtablezInfo* sample);
void PushDead(HashtablezInfo* sample);
HashtablezInfo* PopDead();
std::atomic<size_t> dropped_samples_;
std::atomic<size_t> size_estimate_;
// Intrusive lock free linked lists for tracking samples.
//
// `all_` records all samples (they are never removed from this list) and is
// terminated with a `nullptr`.
//
// `graveyard_.dead` is a circular linked list. When it is empty,
// `graveyard_.dead == &graveyard`. The list is circular so that
// every item on it (even the last) has a non-null dead pointer. This allows
// `Iterate` to determine if a given sample is live or dead using only
// information on the sample itself.
//
// For example, nodes [A, B, C, D, E] with [A, C, E] alive and [B, D] dead
// looks like this (G is the Graveyard):
//
// +---+ +---+ +---+ +---+ +---+
// all -->| A |--->| B |--->| C |--->| D |--->| E |
// | | | | | | | | | |
// +---+ | | +->| |-+ | | +->| |-+ | |
// | G | +---+ | +---+ | +---+ | +---+ | +---+
// | | | | | |
// | | --------+ +--------+ |
// +---+ |
// ^ |
// +--------------------------------------+
//
std::atomic<HashtablezInfo*> all_;
HashtablezInfo graveyard_;
};
// Enables or disables sampling for Swiss tables.
void SetHashtablezEnabled(bool enabled);
// Sets the rate at which Swiss tables will be sampled.
void SetHashtablezSampleParameter(int32_t rate);
// Sets a soft max for the number of samples that will be kept.
void SetHashtablezMaxSamples(int32_t max);
} // namespace container_internal
} // namespace absl
#endif // ABSL_CONTAINER_INTERNAL_HASHTABLEZ_SAMPLER_H_