Abseil Common Libraries (C++) (grcp 依赖) https://abseil.io/
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Export of internal Abseil changes -- f012012ef78234a6a4585321b67d7b7c92ebc266 by Laramie Leavitt <lar@google.com>: Slight restructuring of absl/random/internal randen implementation. Convert round-keys.inc into randen_round_keys.cc file. Consistently use a 128-bit pointer type for internal method parameters. This allows simpler pointer arithmetic in C++ & permits removal of some constants and casts. Remove some redundancy in comments & constexpr variables. Specifically, all references to Randen algorithm parameters use RandenTraits; duplication in RandenSlow removed. PiperOrigin-RevId: 312190313 -- dc8b42e054046741e9ed65335bfdface997c6063 by Abseil Team <absl-team@google.com>: Internal change. PiperOrigin-RevId: 312167304 -- f13d248fafaf206492c1362c3574031aea3abaf7 by Matthew Brown <matthewbr@google.com>: Cleanup StrFormat extensions a little. PiperOrigin-RevId: 312166336 -- 9d9117589667afe2332bb7ad42bc967ca7c54502 by Derek Mauro <dmauro@google.com>: Internal change PiperOrigin-RevId: 312105213 -- 9a12b9b3aa0e59b8ee6cf9408ed0029045543a9b by Abseil Team <absl-team@google.com>: Complete IGNORE_TYPE macro renaming. PiperOrigin-RevId: 311999699 -- 64756f20d61021d999bd0d4c15e9ad3857382f57 by Gennadiy Rozental <rogeeff@google.com>: Switch to fixed bytes specific default value. This fixes the Abseil Flags for big endian platforms. PiperOrigin-RevId: 311844448 -- bdbe6b5b29791dbc3816ada1828458b3010ff1e9 by Laramie Leavitt <lar@google.com>: Change many distribution tests to use pcg_engine as a deterministic source of entropy. It's reasonable to test that the BitGen itself has good entropy, however when testing the cross product of all random distributions x all the architecture variations x all submitted changes results in a large number of tests. In order to account for these failures while still using good entropy requires that our allowed sigma need to account for all of these independent tests. Our current sigma values are too restrictive, and we see a lot of failures, so we have to either relax the sigma values or convert some of the statistical tests to use deterministic values. This changelist does the latter. PiperOrigin-RevId: 311840096 GitOrigin-RevId: f012012ef78234a6a4585321b67d7b7c92ebc266 Change-Id: Ic84886f38ff30d7d72c126e9b63c9a61eb729a1a
5 years ago
// Copyright 2017 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.
#include "absl/synchronization/mutex.h"
#ifdef _WIN32
#include <windows.h>
#endif
#include <algorithm>
#include <atomic>
#include <cstdlib>
#include <functional>
#include <memory>
#include <random>
#include <string>
#include <thread> // NOLINT(build/c++11)
#include <vector>
#include "gtest/gtest.h"
#include "absl/base/attributes.h"
#include "absl/base/internal/raw_logging.h"
#include "absl/base/internal/sysinfo.h"
#include "absl/memory/memory.h"
#include "absl/synchronization/internal/thread_pool.h"
#include "absl/time/clock.h"
#include "absl/time/time.h"
namespace {
// TODO(dmauro): Replace with a commandline flag.
static constexpr bool kExtendedTest = false;
std::unique_ptr<absl::synchronization_internal::ThreadPool> CreatePool(
int threads) {
return absl::make_unique<absl::synchronization_internal::ThreadPool>(threads);
}
std::unique_ptr<absl::synchronization_internal::ThreadPool>
CreateDefaultPool() {
return CreatePool(kExtendedTest ? 32 : 10);
}
// Hack to schedule a function to run on a thread pool thread after a
// duration has elapsed.
static void ScheduleAfter(absl::synchronization_internal::ThreadPool *tp,
absl::Duration after,
const std::function<void()> &func) {
tp->Schedule([func, after] {
absl::SleepFor(after);
func();
});
}
struct TestContext {
int iterations;
int threads;
int g0; // global 0
int g1; // global 1
absl::Mutex mu;
absl::CondVar cv;
};
// To test whether the invariant check call occurs
static std::atomic<bool> invariant_checked;
static bool GetInvariantChecked() {
return invariant_checked.load(std::memory_order_relaxed);
}
static void SetInvariantChecked(bool new_value) {
invariant_checked.store(new_value, std::memory_order_relaxed);
}
static void CheckSumG0G1(void *v) {
TestContext *cxt = static_cast<TestContext *>(v);
ABSL_RAW_CHECK(cxt->g0 == -cxt->g1, "Error in CheckSumG0G1");
SetInvariantChecked(true);
}
static void TestMu(TestContext *cxt, int c) {
for (int i = 0; i != cxt->iterations; i++) {
absl::MutexLock l(&cxt->mu);
int a = cxt->g0 + 1;
cxt->g0 = a;
cxt->g1--;
}
}
static void TestTry(TestContext *cxt, int c) {
for (int i = 0; i != cxt->iterations; i++) {
do {
std::this_thread::yield();
} while (!cxt->mu.TryLock());
int a = cxt->g0 + 1;
cxt->g0 = a;
cxt->g1--;
cxt->mu.Unlock();
}
}
static void TestR20ms(TestContext *cxt, int c) {
for (int i = 0; i != cxt->iterations; i++) {
absl::ReaderMutexLock l(&cxt->mu);
absl::SleepFor(absl::Milliseconds(20));
cxt->mu.AssertReaderHeld();
}
}
static void TestRW(TestContext *cxt, int c) {
if ((c & 1) == 0) {
for (int i = 0; i != cxt->iterations; i++) {
absl::WriterMutexLock l(&cxt->mu);
cxt->g0++;
cxt->g1--;
cxt->mu.AssertHeld();
cxt->mu.AssertReaderHeld();
}
} else {
for (int i = 0; i != cxt->iterations; i++) {
absl::ReaderMutexLock l(&cxt->mu);
ABSL_RAW_CHECK(cxt->g0 == -cxt->g1, "Error in TestRW");
cxt->mu.AssertReaderHeld();
}
}
}
struct MyContext {
int target;
TestContext *cxt;
bool MyTurn();
};
bool MyContext::MyTurn() {
TestContext *cxt = this->cxt;
return cxt->g0 == this->target || cxt->g0 == cxt->iterations;
}
static void TestAwait(TestContext *cxt, int c) {
MyContext mc;
mc.target = c;
mc.cxt = cxt;
absl::MutexLock l(&cxt->mu);
cxt->mu.AssertHeld();
while (cxt->g0 < cxt->iterations) {
cxt->mu.Await(absl::Condition(&mc, &MyContext::MyTurn));
ABSL_RAW_CHECK(mc.MyTurn(), "Error in TestAwait");
cxt->mu.AssertHeld();
if (cxt->g0 < cxt->iterations) {
int a = cxt->g0 + 1;
cxt->g0 = a;
mc.target += cxt->threads;
}
}
}
static void TestSignalAll(TestContext *cxt, int c) {
int target = c;
absl::MutexLock l(&cxt->mu);
cxt->mu.AssertHeld();
while (cxt->g0 < cxt->iterations) {
while (cxt->g0 != target && cxt->g0 != cxt->iterations) {
cxt->cv.Wait(&cxt->mu);
}
if (cxt->g0 < cxt->iterations) {
int a = cxt->g0 + 1;
cxt->g0 = a;
cxt->cv.SignalAll();
target += cxt->threads;
}
}
}
static void TestSignal(TestContext *cxt, int c) {
ABSL_RAW_CHECK(cxt->threads == 2, "TestSignal should use 2 threads");
int target = c;
absl::MutexLock l(&cxt->mu);
cxt->mu.AssertHeld();
while (cxt->g0 < cxt->iterations) {
while (cxt->g0 != target && cxt->g0 != cxt->iterations) {
cxt->cv.Wait(&cxt->mu);
}
if (cxt->g0 < cxt->iterations) {
int a = cxt->g0 + 1;
cxt->g0 = a;
cxt->cv.Signal();
target += cxt->threads;
}
}
}
static void TestCVTimeout(TestContext *cxt, int c) {
int target = c;
absl::MutexLock l(&cxt->mu);
cxt->mu.AssertHeld();
while (cxt->g0 < cxt->iterations) {
while (cxt->g0 != target && cxt->g0 != cxt->iterations) {
cxt->cv.WaitWithTimeout(&cxt->mu, absl::Seconds(100));
}
if (cxt->g0 < cxt->iterations) {
int a = cxt->g0 + 1;
cxt->g0 = a;
cxt->cv.SignalAll();
target += cxt->threads;
}
}
}
static bool G0GE2(TestContext *cxt) { return cxt->g0 >= 2; }
static void TestTime(TestContext *cxt, int c, bool use_cv) {
ABSL_RAW_CHECK(cxt->iterations == 1, "TestTime should only use 1 iteration");
ABSL_RAW_CHECK(cxt->threads > 2, "TestTime should use more than 2 threads");
const bool kFalse = false;
absl::Condition false_cond(&kFalse);
absl::Condition g0ge2(G0GE2, cxt);
if (c == 0) {
absl::MutexLock l(&cxt->mu);
absl::Time start = absl::Now();
if (use_cv) {
cxt->cv.WaitWithTimeout(&cxt->mu, absl::Seconds(1));
} else {
ABSL_RAW_CHECK(!cxt->mu.AwaitWithTimeout(false_cond, absl::Seconds(1)),
"TestTime failed");
}
absl::Duration elapsed = absl::Now() - start;
ABSL_RAW_CHECK(
absl::Seconds(0.9) <= elapsed && elapsed <= absl::Seconds(2.0),
"TestTime failed");
ABSL_RAW_CHECK(cxt->g0 == 1, "TestTime failed");
start = absl::Now();
if (use_cv) {
cxt->cv.WaitWithTimeout(&cxt->mu, absl::Seconds(1));
} else {
ABSL_RAW_CHECK(!cxt->mu.AwaitWithTimeout(false_cond, absl::Seconds(1)),
"TestTime failed");
}
elapsed = absl::Now() - start;
ABSL_RAW_CHECK(
absl::Seconds(0.9) <= elapsed && elapsed <= absl::Seconds(2.0),
"TestTime failed");
cxt->g0++;
if (use_cv) {
cxt->cv.Signal();
}
start = absl::Now();
if (use_cv) {
cxt->cv.WaitWithTimeout(&cxt->mu, absl::Seconds(4));
} else {
ABSL_RAW_CHECK(!cxt->mu.AwaitWithTimeout(false_cond, absl::Seconds(4)),
"TestTime failed");
}
elapsed = absl::Now() - start;
ABSL_RAW_CHECK(
absl::Seconds(3.9) <= elapsed && elapsed <= absl::Seconds(6.0),
"TestTime failed");
ABSL_RAW_CHECK(cxt->g0 >= 3, "TestTime failed");
start = absl::Now();
if (use_cv) {
cxt->cv.WaitWithTimeout(&cxt->mu, absl::Seconds(1));
} else {
ABSL_RAW_CHECK(!cxt->mu.AwaitWithTimeout(false_cond, absl::Seconds(1)),
"TestTime failed");
}
elapsed = absl::Now() - start;
ABSL_RAW_CHECK(
absl::Seconds(0.9) <= elapsed && elapsed <= absl::Seconds(2.0),
"TestTime failed");
if (use_cv) {
cxt->cv.SignalAll();
}
start = absl::Now();
if (use_cv) {
cxt->cv.WaitWithTimeout(&cxt->mu, absl::Seconds(1));
} else {
ABSL_RAW_CHECK(!cxt->mu.AwaitWithTimeout(false_cond, absl::Seconds(1)),
"TestTime failed");
}
elapsed = absl::Now() - start;
ABSL_RAW_CHECK(absl::Seconds(0.9) <= elapsed &&
elapsed <= absl::Seconds(2.0), "TestTime failed");
ABSL_RAW_CHECK(cxt->g0 == cxt->threads, "TestTime failed");
} else if (c == 1) {
absl::MutexLock l(&cxt->mu);
const absl::Time start = absl::Now();
if (use_cv) {
cxt->cv.WaitWithTimeout(&cxt->mu, absl::Milliseconds(500));
} else {
ABSL_RAW_CHECK(
!cxt->mu.AwaitWithTimeout(false_cond, absl::Milliseconds(500)),
"TestTime failed");
}
const absl::Duration elapsed = absl::Now() - start;
ABSL_RAW_CHECK(
absl::Seconds(0.4) <= elapsed && elapsed <= absl::Seconds(0.9),
"TestTime failed");
cxt->g0++;
} else if (c == 2) {
absl::MutexLock l(&cxt->mu);
if (use_cv) {
while (cxt->g0 < 2) {
cxt->cv.WaitWithTimeout(&cxt->mu, absl::Seconds(100));
}
} else {
ABSL_RAW_CHECK(cxt->mu.AwaitWithTimeout(g0ge2, absl::Seconds(100)),
"TestTime failed");
}
cxt->g0++;
} else {
absl::MutexLock l(&cxt->mu);
if (use_cv) {
while (cxt->g0 < 2) {
cxt->cv.Wait(&cxt->mu);
}
} else {
cxt->mu.Await(g0ge2);
}
cxt->g0++;
}
}
static void TestMuTime(TestContext *cxt, int c) { TestTime(cxt, c, false); }
static void TestCVTime(TestContext *cxt, int c) { TestTime(cxt, c, true); }
static void EndTest(int *c0, int *c1, absl::Mutex *mu, absl::CondVar *cv,
const std::function<void(int)>& cb) {
mu->Lock();
int c = (*c0)++;
mu->Unlock();
cb(c);
absl::MutexLock l(mu);
(*c1)++;
cv->Signal();
}
// Code common to RunTest() and RunTestWithInvariantDebugging().
static int RunTestCommon(TestContext *cxt, void (*test)(TestContext *cxt, int),
int threads, int iterations, int operations) {
absl::Mutex mu2;
absl::CondVar cv2;
int c0 = 0;
int c1 = 0;
cxt->g0 = 0;
cxt->g1 = 0;
cxt->iterations = iterations;
cxt->threads = threads;
absl::synchronization_internal::ThreadPool tp(threads);
for (int i = 0; i != threads; i++) {
tp.Schedule(std::bind(&EndTest, &c0, &c1, &mu2, &cv2,
std::function<void(int)>(
std::bind(test, cxt, std::placeholders::_1))));
}
mu2.Lock();
while (c1 != threads) {
cv2.Wait(&mu2);
}
mu2.Unlock();
return cxt->g0;
}
// Basis for the parameterized tests configured below.
static int RunTest(void (*test)(TestContext *cxt, int), int threads,
int iterations, int operations) {
TestContext cxt;
return RunTestCommon(&cxt, test, threads, iterations, operations);
}
// Like RunTest(), but sets an invariant on the tested Mutex and
// verifies that the invariant check happened. The invariant function
// will be passed the TestContext* as its arg and must call
// SetInvariantChecked(true);
#if !defined(ABSL_MUTEX_ENABLE_INVARIANT_DEBUGGING_NOT_IMPLEMENTED)
static int RunTestWithInvariantDebugging(void (*test)(TestContext *cxt, int),
int threads, int iterations,
int operations,
void (*invariant)(void *)) {
absl::EnableMutexInvariantDebugging(true);
SetInvariantChecked(false);
TestContext cxt;
cxt.mu.EnableInvariantDebugging(invariant, &cxt);
int ret = RunTestCommon(&cxt, test, threads, iterations, operations);
ABSL_RAW_CHECK(GetInvariantChecked(), "Invariant not checked");
absl::EnableMutexInvariantDebugging(false); // Restore.
return ret;
}
#endif
// --------------------------------------------------------
// Test for fix of bug in TryRemove()
struct TimeoutBugStruct {
absl::Mutex mu;
bool a;
int a_waiter_count;
};
static void WaitForA(TimeoutBugStruct *x) {
x->mu.LockWhen(absl::Condition(&x->a));
x->a_waiter_count--;
x->mu.Unlock();
}
static bool NoAWaiters(TimeoutBugStruct *x) { return x->a_waiter_count == 0; }
// Test that a CondVar.Wait(&mutex) can un-block a call to mutex.Await() in
// another thread.
TEST(Mutex, CondVarWaitSignalsAwait) {
// Use a struct so the lock annotations apply.
struct {
absl::Mutex barrier_mu;
bool barrier ABSL_GUARDED_BY(barrier_mu) = false;
absl::Mutex release_mu;
bool release ABSL_GUARDED_BY(release_mu) = false;
absl::CondVar released_cv;
} state;
auto pool = CreateDefaultPool();
// Thread A. Sets barrier, waits for release using Mutex::Await, then
// signals released_cv.
pool->Schedule([&state] {
state.release_mu.Lock();
state.barrier_mu.Lock();
state.barrier = true;
state.barrier_mu.Unlock();
state.release_mu.Await(absl::Condition(&state.release));
state.released_cv.Signal();
state.release_mu.Unlock();
});
state.barrier_mu.LockWhen(absl::Condition(&state.barrier));
state.barrier_mu.Unlock();
state.release_mu.Lock();
// Thread A is now blocked on release by way of Mutex::Await().
// Set release. Calling released_cv.Wait() should un-block thread A,
// which will signal released_cv. If not, the test will hang.
state.release = true;
state.released_cv.Wait(&state.release_mu);
state.release_mu.Unlock();
}
// Test that a CondVar.WaitWithTimeout(&mutex) can un-block a call to
// mutex.Await() in another thread.
TEST(Mutex, CondVarWaitWithTimeoutSignalsAwait) {
// Use a struct so the lock annotations apply.
struct {
absl::Mutex barrier_mu;
bool barrier ABSL_GUARDED_BY(barrier_mu) = false;
absl::Mutex release_mu;
bool release ABSL_GUARDED_BY(release_mu) = false;
absl::CondVar released_cv;
} state;
auto pool = CreateDefaultPool();
// Thread A. Sets barrier, waits for release using Mutex::Await, then
// signals released_cv.
pool->Schedule([&state] {
state.release_mu.Lock();
state.barrier_mu.Lock();
state.barrier = true;
state.barrier_mu.Unlock();
state.release_mu.Await(absl::Condition(&state.release));
state.released_cv.Signal();
state.release_mu.Unlock();
});
state.barrier_mu.LockWhen(absl::Condition(&state.barrier));
state.barrier_mu.Unlock();
state.release_mu.Lock();
// Thread A is now blocked on release by way of Mutex::Await().
// Set release. Calling released_cv.Wait() should un-block thread A,
// which will signal released_cv. If not, the test will hang.
state.release = true;
EXPECT_TRUE(
!state.released_cv.WaitWithTimeout(&state.release_mu, absl::Seconds(10)))
<< "; Unrecoverable test failure: CondVar::WaitWithTimeout did not "
"unblock the absl::Mutex::Await call in another thread.";
state.release_mu.Unlock();
}
// Test for regression of a bug in loop of TryRemove()
TEST(Mutex, MutexTimeoutBug) {
auto tp = CreateDefaultPool();
TimeoutBugStruct x;
x.a = false;
x.a_waiter_count = 2;
tp->Schedule(std::bind(&WaitForA, &x));
tp->Schedule(std::bind(&WaitForA, &x));
absl::SleepFor(absl::Seconds(1)); // Allow first two threads to hang.
// The skip field of the second will point to the first because there are
// only two.
// Now cause a thread waiting on an always-false to time out
// This would deadlock when the bug was present.
bool always_false = false;
x.mu.LockWhenWithTimeout(absl::Condition(&always_false),
absl::Milliseconds(500));
// if we get here, the bug is not present. Cleanup the state.
x.a = true; // wakeup the two waiters on A
x.mu.Await(absl::Condition(&NoAWaiters, &x)); // wait for them to exit
x.mu.Unlock();
}
struct CondVarWaitDeadlock : testing::TestWithParam<int> {
absl::Mutex mu;
absl::CondVar cv;
bool cond1 = false;
bool cond2 = false;
bool read_lock1;
bool read_lock2;
bool signal_unlocked;
CondVarWaitDeadlock() {
read_lock1 = GetParam() & (1 << 0);
read_lock2 = GetParam() & (1 << 1);
signal_unlocked = GetParam() & (1 << 2);
}
void Waiter1() {
if (read_lock1) {
mu.ReaderLock();
while (!cond1) {
cv.Wait(&mu);
}
mu.ReaderUnlock();
} else {
mu.Lock();
while (!cond1) {
cv.Wait(&mu);
}
mu.Unlock();
}
}
void Waiter2() {
if (read_lock2) {
mu.ReaderLockWhen(absl::Condition(&cond2));
mu.ReaderUnlock();
} else {
mu.LockWhen(absl::Condition(&cond2));
mu.Unlock();
}
}
};
// Test for a deadlock bug in Mutex::Fer().
// The sequence of events that lead to the deadlock is:
// 1. waiter1 blocks on cv in read mode (mu bits = 0).
// 2. waiter2 blocks on mu in either mode (mu bits = kMuWait).
// 3. main thread locks mu, sets cond1, unlocks mu (mu bits = kMuWait).
// 4. main thread signals on cv and this eventually calls Mutex::Fer().
// Currently Fer wakes waiter1 since mu bits = kMuWait (mutex is unlocked).
// Before the bug fix Fer neither woke waiter1 nor queued it on mutex,
// which resulted in deadlock.
TEST_P(CondVarWaitDeadlock, Test) {
auto waiter1 = CreatePool(1);
auto waiter2 = CreatePool(1);
waiter1->Schedule([this] { this->Waiter1(); });
waiter2->Schedule([this] { this->Waiter2(); });
// Wait while threads block (best-effort is fine).
absl::SleepFor(absl::Milliseconds(100));
// Wake condwaiter.
mu.Lock();
cond1 = true;
if (signal_unlocked) {
mu.Unlock();
cv.Signal();
} else {
cv.Signal();
mu.Unlock();
}
waiter1.reset(); // "join" waiter1
// Wake waiter.
mu.Lock();
cond2 = true;
mu.Unlock();
waiter2.reset(); // "join" waiter2
}
INSTANTIATE_TEST_SUITE_P(CondVarWaitDeadlockTest, CondVarWaitDeadlock,
::testing::Range(0, 8),
::testing::PrintToStringParamName());
// --------------------------------------------------------
// Test for fix of bug in DequeueAllWakeable()
// Bug was that if there was more than one waiting reader
// and all should be woken, the most recently blocked one
// would not be.
struct DequeueAllWakeableBugStruct {
absl::Mutex mu;
absl::Mutex mu2; // protects all fields below
int unfinished_count; // count of unfinished readers; under mu2
bool done1; // unfinished_count == 0; under mu2
int finished_count; // count of finished readers, under mu2
bool done2; // finished_count == 0; under mu2
};
// Test for regression of a bug in loop of DequeueAllWakeable()
static void AcquireAsReader(DequeueAllWakeableBugStruct *x) {
x->mu.ReaderLock();
x->mu2.Lock();
x->unfinished_count--;
x->done1 = (x->unfinished_count == 0);
x->mu2.Unlock();
// make sure that both readers acquired mu before we release it.
absl::SleepFor(absl::Seconds(2));
x->mu.ReaderUnlock();
x->mu2.Lock();
x->finished_count--;
x->done2 = (x->finished_count == 0);
x->mu2.Unlock();
}
// Test for regression of a bug in loop of DequeueAllWakeable()
TEST(Mutex, MutexReaderWakeupBug) {
auto tp = CreateDefaultPool();
DequeueAllWakeableBugStruct x;
x.unfinished_count = 2;
x.done1 = false;
x.finished_count = 2;
x.done2 = false;
x.mu.Lock(); // acquire mu exclusively
// queue two thread that will block on reader locks on x.mu
tp->Schedule(std::bind(&AcquireAsReader, &x));
tp->Schedule(std::bind(&AcquireAsReader, &x));
absl::SleepFor(absl::Seconds(1)); // give time for reader threads to block
x.mu.Unlock(); // wake them up
// both readers should finish promptly
EXPECT_TRUE(
x.mu2.LockWhenWithTimeout(absl::Condition(&x.done1), absl::Seconds(10)));
x.mu2.Unlock();
EXPECT_TRUE(
x.mu2.LockWhenWithTimeout(absl::Condition(&x.done2), absl::Seconds(10)));
x.mu2.Unlock();
}
struct LockWhenTestStruct {
absl::Mutex mu1;
bool cond = false;
absl::Mutex mu2;
bool waiting = false;
};
static bool LockWhenTestIsCond(LockWhenTestStruct* s) {
s->mu2.Lock();
s->waiting = true;
s->mu2.Unlock();
return s->cond;
}
static void LockWhenTestWaitForIsCond(LockWhenTestStruct* s) {
s->mu1.LockWhen(absl::Condition(&LockWhenTestIsCond, s));
s->mu1.Unlock();
}
TEST(Mutex, LockWhen) {
LockWhenTestStruct s;
std::thread t(LockWhenTestWaitForIsCond, &s);
s.mu2.LockWhen(absl::Condition(&s.waiting));
s.mu2.Unlock();
s.mu1.Lock();
s.cond = true;
s.mu1.Unlock();
t.join();
}
// --------------------------------------------------------
// The following test requires Mutex::ReaderLock to be a real shared
// lock, which is not the case in all builds.
#if !defined(ABSL_MUTEX_READER_LOCK_IS_EXCLUSIVE)
// Test for fix of bug in UnlockSlow() that incorrectly decremented the reader
// count when putting a thread to sleep waiting for a false condition when the
// lock was not held.
// For this bug to strike, we make a thread wait on a free mutex with no
// waiters by causing its wakeup condition to be false. Then the
// next two acquirers must be readers. The bug causes the lock
// to be released when one reader unlocks, rather than both.
struct ReaderDecrementBugStruct {
bool cond; // to delay first thread (under mu)
int done; // reference count (under mu)
absl::Mutex mu;
bool waiting_on_cond; // under mu2
bool have_reader_lock; // under mu2
bool complete; // under mu2
absl::Mutex mu2; // > mu
};
// L >= mu, L < mu_waiting_on_cond
static bool IsCond(void *v) {
ReaderDecrementBugStruct *x = reinterpret_cast<ReaderDecrementBugStruct *>(v);
x->mu2.Lock();
x->waiting_on_cond = true;
x->mu2.Unlock();
return x->cond;
}
// L >= mu
static bool AllDone(void *v) {
ReaderDecrementBugStruct *x = reinterpret_cast<ReaderDecrementBugStruct *>(v);
return x->done == 0;
}
// L={}
static void WaitForCond(ReaderDecrementBugStruct *x) {
absl::Mutex dummy;
absl::MutexLock l(&dummy);
x->mu.LockWhen(absl::Condition(&IsCond, x));
x->done--;
x->mu.Unlock();
}
// L={}
static void GetReadLock(ReaderDecrementBugStruct *x) {
x->mu.ReaderLock();
x->mu2.Lock();
x->have_reader_lock = true;
x->mu2.Await(absl::Condition(&x->complete));
x->mu2.Unlock();
x->mu.ReaderUnlock();
x->mu.Lock();
x->done--;
x->mu.Unlock();
}
// Test for reader counter being decremented incorrectly by waiter
// with false condition.
TEST(Mutex, MutexReaderDecrementBug) ABSL_NO_THREAD_SAFETY_ANALYSIS {
ReaderDecrementBugStruct x;
x.cond = false;
x.waiting_on_cond = false;
x.have_reader_lock = false;
x.complete = false;
x.done = 2; // initial ref count
// Run WaitForCond() and wait for it to sleep
std::thread thread1(WaitForCond, &x);
x.mu2.LockWhen(absl::Condition(&x.waiting_on_cond));
x.mu2.Unlock();
// Run GetReadLock(), and wait for it to get the read lock
std::thread thread2(GetReadLock, &x);
x.mu2.LockWhen(absl::Condition(&x.have_reader_lock));
x.mu2.Unlock();
// Get the reader lock ourselves, and release it.
x.mu.ReaderLock();
x.mu.ReaderUnlock();
// The lock should be held in read mode by GetReadLock().
// If we have the bug, the lock will be free.
x.mu.AssertReaderHeld();
// Wake up all the threads.
x.mu2.Lock();
x.complete = true;
x.mu2.Unlock();
// TODO(delesley): turn on analysis once lock upgrading is supported.
// (This call upgrades the lock from shared to exclusive.)
x.mu.Lock();
x.cond = true;
x.mu.Await(absl::Condition(&AllDone, &x));
x.mu.Unlock();
thread1.join();
thread2.join();
}
#endif // !ABSL_MUTEX_READER_LOCK_IS_EXCLUSIVE
// Test that we correctly handle the situation when a lock is
// held and then destroyed (w/o unlocking).
#ifdef THREAD_SANITIZER
// TSAN reports errors when locked Mutexes are destroyed.
TEST(Mutex, DISABLED_LockedMutexDestructionBug) NO_THREAD_SAFETY_ANALYSIS {
#else
TEST(Mutex, LockedMutexDestructionBug) ABSL_NO_THREAD_SAFETY_ANALYSIS {
#endif
for (int i = 0; i != 10; i++) {
// Create, lock and destroy 10 locks.
const int kNumLocks = 10;
auto mu = absl::make_unique<absl::Mutex[]>(kNumLocks);
for (int j = 0; j != kNumLocks; j++) {
if ((j % 2) == 0) {
mu[j].WriterLock();
} else {
mu[j].ReaderLock();
}
}
}
}
// --------------------------------------------------------
// Test for bug with pattern of readers using a condvar. The bug was that if a
// reader went to sleep on a condition variable while one or more other readers
// held the lock, but there were no waiters, the reader count (held in the
// mutex word) would be lost. (This is because Enqueue() had at one time
// always placed the thread on the Mutex queue. Later (CL 4075610), to
// tolerate re-entry into Mutex from a Condition predicate, Enqueue() was
// changed so that it could also place a thread on a condition-variable. This
// introduced the case where Enqueue() returned with an empty queue, and this
// case was handled incorrectly in one place.)
static void ReaderForReaderOnCondVar(absl::Mutex *mu, absl::CondVar *cv,
int *running) {
std::random_device dev;
std::mt19937 gen(dev());
std::uniform_int_distribution<int> random_millis(0, 15);
mu->ReaderLock();
while (*running == 3) {
absl::SleepFor(absl::Milliseconds(random_millis(gen)));
cv->WaitWithTimeout(mu, absl::Milliseconds(random_millis(gen)));
}
mu->ReaderUnlock();
mu->Lock();
(*running)--;
mu->Unlock();
}
struct True {
template <class... Args>
bool operator()(Args...) const {
return true;
}
};
struct DerivedTrue : True {};
TEST(Mutex, FunctorCondition) {
{ // Variadic
True f;
EXPECT_TRUE(absl::Condition(&f).Eval());
}
{ // Inherited
DerivedTrue g;
EXPECT_TRUE(absl::Condition(&g).Eval());
}
{ // lambda
int value = 3;
auto is_zero = [&value] { return value == 0; };
absl::Condition c(&is_zero);
EXPECT_FALSE(c.Eval());
value = 0;
EXPECT_TRUE(c.Eval());
}
{ // bind
int value = 0;
auto is_positive = std::bind(std::less<int>(), 0, std::cref(value));
absl::Condition c(&is_positive);
EXPECT_FALSE(c.Eval());
value = 1;
EXPECT_TRUE(c.Eval());
}
{ // std::function
int value = 3;
std::function<bool()> is_zero = [&value] { return value == 0; };
absl::Condition c(&is_zero);
EXPECT_FALSE(c.Eval());
value = 0;
EXPECT_TRUE(c.Eval());
}
}
static bool IntIsZero(int *x) { return *x == 0; }
// Test for reader waiting condition variable when there are other readers
// but no waiters.
TEST(Mutex, TestReaderOnCondVar) {
auto tp = CreateDefaultPool();
absl::Mutex mu;
absl::CondVar cv;
int running = 3;
tp->Schedule(std::bind(&ReaderForReaderOnCondVar, &mu, &cv, &running));
tp->Schedule(std::bind(&ReaderForReaderOnCondVar, &mu, &cv, &running));
absl::SleepFor(absl::Seconds(2));
mu.Lock();
running--;
mu.Await(absl::Condition(&IntIsZero, &running));
mu.Unlock();
}
// --------------------------------------------------------
struct AcquireFromConditionStruct {
absl::Mutex mu0; // protects value, done
int value; // times condition function is called; under mu0,
bool done; // done with test? under mu0
absl::Mutex mu1; // used to attempt to mess up state of mu0
absl::CondVar cv; // so the condition function can be invoked from
// CondVar::Wait().
};
static bool ConditionWithAcquire(AcquireFromConditionStruct *x) {
x->value++; // count times this function is called
if (x->value == 2 || x->value == 3) {
// On the second and third invocation of this function, sleep for 100ms,
// but with the side-effect of altering the state of a Mutex other than
// than one for which this is a condition. The spec now explicitly allows
// this side effect; previously it did not. it was illegal.
bool always_false = false;
x->mu1.LockWhenWithTimeout(absl::Condition(&always_false),
absl::Milliseconds(100));
x->mu1.Unlock();
}
ABSL_RAW_CHECK(x->value < 4, "should not be invoked a fourth time");
// We arrange for the condition to return true on only the 2nd and 3rd calls.
return x->value == 2 || x->value == 3;
}
static void WaitForCond2(AcquireFromConditionStruct *x) {
// wait for cond0 to become true
x->mu0.LockWhen(absl::Condition(&ConditionWithAcquire, x));
x->done = true;
x->mu0.Unlock();
}
// Test for Condition whose function acquires other Mutexes
TEST(Mutex, AcquireFromCondition) {
auto tp = CreateDefaultPool();
AcquireFromConditionStruct x;
x.value = 0;
x.done = false;
tp->Schedule(
std::bind(&WaitForCond2, &x)); // run WaitForCond2() in a thread T
// T will hang because the first invocation of ConditionWithAcquire() will
// return false.
absl::SleepFor(absl::Milliseconds(500)); // allow T time to hang
x.mu0.Lock();
x.cv.WaitWithTimeout(&x.mu0, absl::Milliseconds(500)); // wake T
// T will be woken because the Wait() will call ConditionWithAcquire()
// for the second time, and it will return true.
x.mu0.Unlock();
// T will then acquire the lock and recheck its own condition.
// It will find the condition true, as this is the third invocation,
// but the use of another Mutex by the calling function will
// cause the old mutex implementation to think that the outer
// LockWhen() has timed out because the inner LockWhenWithTimeout() did.
// T will then check the condition a fourth time because it finds a
// timeout occurred. This should not happen in the new
// implementation that allows the Condition function to use Mutexes.
// It should also succeed, even though the Condition function
// is being invoked from CondVar::Wait, and thus this thread
// is conceptually waiting both on the condition variable, and on mu2.
x.mu0.LockWhen(absl::Condition(&x.done));
x.mu0.Unlock();
}
// The deadlock detector is not part of non-prod builds, so do not test it.
#if !defined(ABSL_INTERNAL_USE_NONPROD_MUTEX)
TEST(Mutex, DeadlockDetector) {
absl::SetMutexDeadlockDetectionMode(absl::OnDeadlockCycle::kAbort);
// check that we can call ForgetDeadlockInfo() on a lock with the lock held
absl::Mutex m1;
absl::Mutex m2;
absl::Mutex m3;
absl::Mutex m4;
m1.Lock(); // m1 gets ID1
m2.Lock(); // m2 gets ID2
m3.Lock(); // m3 gets ID3
m3.Unlock();
m2.Unlock();
// m1 still held
m1.ForgetDeadlockInfo(); // m1 loses ID
m2.Lock(); // m2 gets ID2
m3.Lock(); // m3 gets ID3
m4.Lock(); // m4 gets ID4
m3.Unlock();
m2.Unlock();
m4.Unlock();
m1.Unlock();
}
// Bazel has a test "warning" file that programs can write to if the
// test should pass with a warning. This class disables the warning
// file until it goes out of scope.
class ScopedDisableBazelTestWarnings {
public:
ScopedDisableBazelTestWarnings() {
#ifdef _WIN32
char file[MAX_PATH];
if (GetEnvironmentVariableA(kVarName, file, sizeof(file)) < sizeof(file)) {
warnings_output_file_ = file;
SetEnvironmentVariableA(kVarName, nullptr);
}
#else
const char *file = getenv(kVarName);
if (file != nullptr) {
warnings_output_file_ = file;
unsetenv(kVarName);
}
#endif
}
~ScopedDisableBazelTestWarnings() {
if (!warnings_output_file_.empty()) {
#ifdef _WIN32
SetEnvironmentVariableA(kVarName, warnings_output_file_.c_str());
#else
setenv(kVarName, warnings_output_file_.c_str(), 0);
#endif
}
}
private:
static const char kVarName[];
std::string warnings_output_file_;
};
const char ScopedDisableBazelTestWarnings::kVarName[] =
"TEST_WARNINGS_OUTPUT_FILE";
#ifdef THREAD_SANITIZER
// This test intentionally creates deadlocks to test the deadlock detector.
TEST(Mutex, DISABLED_DeadlockDetectorBazelWarning) {
#else
TEST(Mutex, DeadlockDetectorBazelWarning) {
#endif
absl::SetMutexDeadlockDetectionMode(absl::OnDeadlockCycle::kReport);
// Cause deadlock detection to detect something, if it's
// compiled in and enabled. But turn off the bazel warning.
ScopedDisableBazelTestWarnings disable_bazel_test_warnings;
absl::Mutex mu0;
absl::Mutex mu1;
bool got_mu0 = mu0.TryLock();
mu1.Lock(); // acquire mu1 while holding mu0
if (got_mu0) {
mu0.Unlock();
}
if (mu0.TryLock()) { // try lock shouldn't cause deadlock detector to fire
mu0.Unlock();
}
mu0.Lock(); // acquire mu0 while holding mu1; should get one deadlock
// report here
mu0.Unlock();
mu1.Unlock();
absl::SetMutexDeadlockDetectionMode(absl::OnDeadlockCycle::kAbort);
}
// This test is tagged with NO_THREAD_SAFETY_ANALYSIS because the
// annotation-based static thread-safety analysis is not currently
// predicate-aware and cannot tell if the two for-loops that acquire and
// release the locks have the same predicates.
TEST(Mutex, DeadlockDetectorStessTest) ABSL_NO_THREAD_SAFETY_ANALYSIS {
// Stress test: Here we create a large number of locks and use all of them.
// If a deadlock detector keeps a full graph of lock acquisition order,
// it will likely be too slow for this test to pass.
const int n_locks = 1 << 17;
auto array_of_locks = absl::make_unique<absl::Mutex[]>(n_locks);
for (int i = 0; i < n_locks; i++) {
int end = std::min(n_locks, i + 5);
// acquire and then release locks i, i+1, ..., i+4
for (int j = i; j < end; j++) {
array_of_locks[j].Lock();
}
for (int j = i; j < end; j++) {
array_of_locks[j].Unlock();
}
}
}
#ifdef THREAD_SANITIZER
// TSAN reports errors when locked Mutexes are destroyed.
TEST(Mutex, DISABLED_DeadlockIdBug) NO_THREAD_SAFETY_ANALYSIS {
#else
TEST(Mutex, DeadlockIdBug) ABSL_NO_THREAD_SAFETY_ANALYSIS {
#endif
// Test a scenario where a cached deadlock graph node id in the
// list of held locks is not invalidated when the corresponding
// mutex is deleted.
absl::SetMutexDeadlockDetectionMode(absl::OnDeadlockCycle::kAbort);
// Mutex that will be destroyed while being held
absl::Mutex *a = new absl::Mutex;
// Other mutexes needed by test
absl::Mutex b, c;
// Hold mutex.
a->Lock();
// Force deadlock id assignment by acquiring another lock.
b.Lock();
b.Unlock();
// Delete the mutex. The Mutex destructor tries to remove held locks,
// but the attempt isn't foolproof. It can fail if:
// (a) Deadlock detection is currently disabled.
// (b) The destruction is from another thread.
// We exploit (a) by temporarily disabling deadlock detection.
absl::SetMutexDeadlockDetectionMode(absl::OnDeadlockCycle::kIgnore);
delete a;
absl::SetMutexDeadlockDetectionMode(absl::OnDeadlockCycle::kAbort);
// Now acquire another lock which will force a deadlock id assignment.
// We should end up getting assigned the same deadlock id that was
// freed up when "a" was deleted, which will cause a spurious deadlock
// report if the held lock entry for "a" was not invalidated.
c.Lock();
c.Unlock();
}
#endif // !defined(ABSL_INTERNAL_USE_NONPROD_MUTEX)
// --------------------------------------------------------
// Test for timeouts/deadlines on condition waits that are specified using
// absl::Duration and absl::Time. For each waiting function we test with
// a timeout/deadline that has already expired/passed, one that is infinite
// and so never expires/passes, and one that will expire/pass in the near
// future.
static absl::Duration TimeoutTestAllowedSchedulingDelay() {
// Note: we use a function here because Microsoft Visual Studio fails to
// properly initialize constexpr static absl::Duration variables.
return absl::Milliseconds(150);
}
// Returns true if `actual_delay` is close enough to `expected_delay` to pass
// the timeouts/deadlines test. Otherwise, logs warnings and returns false.
ABSL_MUST_USE_RESULT
static bool DelayIsWithinBounds(absl::Duration expected_delay,
absl::Duration actual_delay) {
bool pass = true;
// Do not allow the observed delay to be less than expected. This may occur
// in practice due to clock skew or when the synchronization primitives use a
// different clock than absl::Now(), but these cases should be handled by the
// the retry mechanism in each TimeoutTest.
if (actual_delay < expected_delay) {
ABSL_RAW_LOG(WARNING,
"Actual delay %s was too short, expected %s (difference %s)",
absl::FormatDuration(actual_delay).c_str(),
absl::FormatDuration(expected_delay).c_str(),
absl::FormatDuration(actual_delay - expected_delay).c_str());
pass = false;
}
// If the expected delay is <= zero then allow a small error tolerance, since
// we do not expect context switches to occur during test execution.
// Otherwise, thread scheduling delays may be substantial in rare cases, so
// tolerate up to kTimeoutTestAllowedSchedulingDelay of error.
absl::Duration tolerance = expected_delay <= absl::ZeroDuration()
? absl::Milliseconds(10)
: TimeoutTestAllowedSchedulingDelay();
if (actual_delay > expected_delay + tolerance) {
ABSL_RAW_LOG(WARNING,
"Actual delay %s was too long, expected %s (difference %s)",
absl::FormatDuration(actual_delay).c_str(),
absl::FormatDuration(expected_delay).c_str(),
absl::FormatDuration(actual_delay - expected_delay).c_str());
pass = false;
}
return pass;
}
// Parameters for TimeoutTest, below.
struct TimeoutTestParam {
// The file and line number (used for logging purposes only).
const char *from_file;
int from_line;
// Should the absolute deadline API based on absl::Time be tested? If false,
// the relative deadline API based on absl::Duration is tested.
bool use_absolute_deadline;
// The deadline/timeout used when calling the API being tested
// (e.g. Mutex::LockWhenWithDeadline).
absl::Duration wait_timeout;
// The delay before the condition will be set true by the test code. If zero
// or negative, the condition is set true immediately (before calling the API
// being tested). Otherwise, if infinite, the condition is never set true.
// Otherwise a closure is scheduled for the future that sets the condition
// true.
absl::Duration satisfy_condition_delay;
// The expected result of the condition after the call to the API being
// tested. Generally `true` means the condition was true when the API returns,
// `false` indicates an expected timeout.
bool expected_result;
// The expected delay before the API under test returns. This is inherently
// flaky, so some slop is allowed (see `DelayIsWithinBounds` above), and the
// test keeps trying indefinitely until this constraint passes.
absl::Duration expected_delay;
};
// Print a `TimeoutTestParam` to a debug log.
std::ostream &operator<<(std::ostream &os, const TimeoutTestParam &param) {
return os << "from: " << param.from_file << ":" << param.from_line
<< " use_absolute_deadline: "
<< (param.use_absolute_deadline ? "true" : "false")
<< " wait_timeout: " << param.wait_timeout
<< " satisfy_condition_delay: " << param.satisfy_condition_delay
<< " expected_result: "
<< (param.expected_result ? "true" : "false")
<< " expected_delay: " << param.expected_delay;
}
std::string FormatString(const TimeoutTestParam &param) {
std::ostringstream os;
os << param;
return os.str();
}
// Like `thread::Executor::ScheduleAt` except:
// a) Delays zero or negative are executed immediately in the current thread.
// b) Infinite delays are never scheduled.
// c) Calls this test's `ScheduleAt` helper instead of using `pool` directly.
static void RunAfterDelay(absl::Duration delay,
absl::synchronization_internal::ThreadPool *pool,
const std::function<void()> &callback) {
if (delay <= absl::ZeroDuration()) {
callback(); // immediate
} else if (delay != absl::InfiniteDuration()) {
ScheduleAfter(pool, delay, callback);
}
}
class TimeoutTest : public ::testing::Test,
public ::testing::WithParamInterface<TimeoutTestParam> {};
std::vector<TimeoutTestParam> MakeTimeoutTestParamValues() {
// The `finite` delay is a finite, relatively short, delay. We make it larger
// than our allowed scheduling delay (slop factor) to avoid confusion when
// diagnosing test failures. The other constants here have clear meanings.
const absl::Duration finite = 3 * TimeoutTestAllowedSchedulingDelay();
const absl::Duration never = absl::InfiniteDuration();
const absl::Duration negative = -absl::InfiniteDuration();
const absl::Duration immediate = absl::ZeroDuration();
// Every test case is run twice; once using the absolute deadline API and once
// using the relative timeout API.
std::vector<TimeoutTestParam> values;
for (bool use_absolute_deadline : {false, true}) {
// Tests with a negative timeout (deadline in the past), which should
// immediately return current state of the condition.
// The condition is already true:
values.push_back(TimeoutTestParam{
__FILE__, __LINE__, use_absolute_deadline,
negative, // wait_timeout
immediate, // satisfy_condition_delay
true, // expected_result
immediate, // expected_delay
});
// The condition becomes true, but the timeout has already expired:
values.push_back(TimeoutTestParam{
__FILE__, __LINE__, use_absolute_deadline,
negative, // wait_timeout
finite, // satisfy_condition_delay
false, // expected_result
immediate // expected_delay
});
// The condition never becomes true:
values.push_back(TimeoutTestParam{
__FILE__, __LINE__, use_absolute_deadline,
negative, // wait_timeout
never, // satisfy_condition_delay
false, // expected_result
immediate // expected_delay
});
// Tests with an infinite timeout (deadline in the infinite future), which
// should only return when the condition becomes true.
// The condition is already true:
values.push_back(TimeoutTestParam{
__FILE__, __LINE__, use_absolute_deadline,
never, // wait_timeout
immediate, // satisfy_condition_delay
true, // expected_result
immediate // expected_delay
});
// The condition becomes true before the (infinite) expiry:
values.push_back(TimeoutTestParam{
__FILE__, __LINE__, use_absolute_deadline,
never, // wait_timeout
finite, // satisfy_condition_delay
true, // expected_result
finite, // expected_delay
});
// Tests with a (small) finite timeout (deadline soon), with the condition
// becoming true both before and after its expiry.
// The condition is already true:
values.push_back(TimeoutTestParam{
__FILE__, __LINE__, use_absolute_deadline,
never, // wait_timeout
immediate, // satisfy_condition_delay
true, // expected_result
immediate // expected_delay
});
// The condition becomes true before the expiry:
values.push_back(TimeoutTestParam{
__FILE__, __LINE__, use_absolute_deadline,
finite * 2, // wait_timeout
finite, // satisfy_condition_delay
true, // expected_result
finite // expected_delay
});
// The condition becomes true, but the timeout has already expired:
values.push_back(TimeoutTestParam{
__FILE__, __LINE__, use_absolute_deadline,
finite, // wait_timeout
finite * 2, // satisfy_condition_delay
false, // expected_result
finite // expected_delay
});
// The condition never becomes true:
values.push_back(TimeoutTestParam{
__FILE__, __LINE__, use_absolute_deadline,
finite, // wait_timeout
never, // satisfy_condition_delay
false, // expected_result
finite // expected_delay
});
}
return values;
}
// Instantiate `TimeoutTest` with `MakeTimeoutTestParamValues()`.
INSTANTIATE_TEST_SUITE_P(All, TimeoutTest,
testing::ValuesIn(MakeTimeoutTestParamValues()));
TEST_P(TimeoutTest, Await) {
const TimeoutTestParam params = GetParam();
ABSL_RAW_LOG(INFO, "Params: %s", FormatString(params).c_str());
// Because this test asserts bounds on scheduling delays it is flaky. To
// compensate it loops forever until it passes. Failures express as test
// timeouts, in which case the test log can be used to diagnose the issue.
for (int attempt = 1;; ++attempt) {
ABSL_RAW_LOG(INFO, "Attempt %d", attempt);
absl::Mutex mu;
bool value = false; // condition value (under mu)
std::unique_ptr<absl::synchronization_internal::ThreadPool> pool =
CreateDefaultPool();
RunAfterDelay(params.satisfy_condition_delay, pool.get(), [&] {
absl::MutexLock l(&mu);
value = true;
});
absl::MutexLock lock(&mu);
absl::Time start_time = absl::Now();
absl::Condition cond(&value);
bool result =
params.use_absolute_deadline
? mu.AwaitWithDeadline(cond, start_time + params.wait_timeout)
: mu.AwaitWithTimeout(cond, params.wait_timeout);
if (DelayIsWithinBounds(params.expected_delay, absl::Now() - start_time)) {
EXPECT_EQ(params.expected_result, result);
break;
}
}
}
TEST_P(TimeoutTest, LockWhen) {
const TimeoutTestParam params = GetParam();
ABSL_RAW_LOG(INFO, "Params: %s", FormatString(params).c_str());
// Because this test asserts bounds on scheduling delays it is flaky. To
// compensate it loops forever until it passes. Failures express as test
// timeouts, in which case the test log can be used to diagnose the issue.
for (int attempt = 1;; ++attempt) {
ABSL_RAW_LOG(INFO, "Attempt %d", attempt);
absl::Mutex mu;
bool value = false; // condition value (under mu)
std::unique_ptr<absl::synchronization_internal::ThreadPool> pool =
CreateDefaultPool();
RunAfterDelay(params.satisfy_condition_delay, pool.get(), [&] {
absl::MutexLock l(&mu);
value = true;
});
absl::Time start_time = absl::Now();
absl::Condition cond(&value);
bool result =
params.use_absolute_deadline
? mu.LockWhenWithDeadline(cond, start_time + params.wait_timeout)
: mu.LockWhenWithTimeout(cond, params.wait_timeout);
mu.Unlock();
if (DelayIsWithinBounds(params.expected_delay, absl::Now() - start_time)) {
EXPECT_EQ(params.expected_result, result);
break;
}
}
}
TEST_P(TimeoutTest, ReaderLockWhen) {
const TimeoutTestParam params = GetParam();
ABSL_RAW_LOG(INFO, "Params: %s", FormatString(params).c_str());
// Because this test asserts bounds on scheduling delays it is flaky. To
// compensate it loops forever until it passes. Failures express as test
// timeouts, in which case the test log can be used to diagnose the issue.
for (int attempt = 0;; ++attempt) {
ABSL_RAW_LOG(INFO, "Attempt %d", attempt);
absl::Mutex mu;
bool value = false; // condition value (under mu)
std::unique_ptr<absl::synchronization_internal::ThreadPool> pool =
CreateDefaultPool();
RunAfterDelay(params.satisfy_condition_delay, pool.get(), [&] {
absl::MutexLock l(&mu);
value = true;
});
absl::Time start_time = absl::Now();
bool result =
params.use_absolute_deadline
? mu.ReaderLockWhenWithDeadline(absl::Condition(&value),
start_time + params.wait_timeout)
: mu.ReaderLockWhenWithTimeout(absl::Condition(&value),
params.wait_timeout);
mu.ReaderUnlock();
if (DelayIsWithinBounds(params.expected_delay, absl::Now() - start_time)) {
EXPECT_EQ(params.expected_result, result);
break;
}
}
}
TEST_P(TimeoutTest, Wait) {
const TimeoutTestParam params = GetParam();
ABSL_RAW_LOG(INFO, "Params: %s", FormatString(params).c_str());
// Because this test asserts bounds on scheduling delays it is flaky. To
// compensate it loops forever until it passes. Failures express as test
// timeouts, in which case the test log can be used to diagnose the issue.
for (int attempt = 0;; ++attempt) {
ABSL_RAW_LOG(INFO, "Attempt %d", attempt);
absl::Mutex mu;
bool value = false; // condition value (under mu)
absl::CondVar cv; // signals a change of `value`
std::unique_ptr<absl::synchronization_internal::ThreadPool> pool =
CreateDefaultPool();
RunAfterDelay(params.satisfy_condition_delay, pool.get(), [&] {
absl::MutexLock l(&mu);
value = true;
cv.Signal();
});
absl::MutexLock lock(&mu);
absl::Time start_time = absl::Now();
absl::Duration timeout = params.wait_timeout;
absl::Time deadline = start_time + timeout;
while (!value) {
if (params.use_absolute_deadline ? cv.WaitWithDeadline(&mu, deadline)
: cv.WaitWithTimeout(&mu, timeout)) {
break; // deadline/timeout exceeded
}
timeout = deadline - absl::Now(); // recompute
}
bool result = value; // note: `mu` is still held
if (DelayIsWithinBounds(params.expected_delay, absl::Now() - start_time)) {
EXPECT_EQ(params.expected_result, result);
break;
}
}
}
TEST(Mutex, Logging) {
// Allow user to look at logging output
absl::Mutex logged_mutex;
logged_mutex.EnableDebugLog("fido_mutex");
absl::CondVar logged_cv;
logged_cv.EnableDebugLog("rover_cv");
logged_mutex.Lock();
logged_cv.WaitWithTimeout(&logged_mutex, absl::Milliseconds(20));
logged_mutex.Unlock();
logged_mutex.ReaderLock();
logged_mutex.ReaderUnlock();
logged_mutex.Lock();
logged_mutex.Unlock();
logged_cv.Signal();
logged_cv.SignalAll();
}
// --------------------------------------------------------
// Generate the vector of thread counts for tests parameterized on thread count.
static std::vector<int> AllThreadCountValues() {
if (kExtendedTest) {
return {2, 4, 8, 10, 16, 20, 24, 30, 32};
}
return {2, 4, 10};
}
// A test fixture parameterized by thread count.
class MutexVariableThreadCountTest : public ::testing::TestWithParam<int> {};
// Instantiate the above with AllThreadCountOptions().
INSTANTIATE_TEST_SUITE_P(ThreadCounts, MutexVariableThreadCountTest,
::testing::ValuesIn(AllThreadCountValues()),
::testing::PrintToStringParamName());
// Reduces iterations by some factor for slow platforms
// (determined empirically).
static int ScaleIterations(int x) {
// ABSL_MUTEX_READER_LOCK_IS_EXCLUSIVE is set in the implementation
// of Mutex that uses either std::mutex or pthread_mutex_t. Use
// these as keys to determine the slow implementation.
#if defined(ABSL_MUTEX_READER_LOCK_IS_EXCLUSIVE)
return x / 10;
#else
return x;
#endif
}
TEST_P(MutexVariableThreadCountTest, Mutex) {
int threads = GetParam();
int iterations = ScaleIterations(10000000) / threads;
int operations = threads * iterations;
EXPECT_EQ(RunTest(&TestMu, threads, iterations, operations), operations);
#if !defined(ABSL_MUTEX_ENABLE_INVARIANT_DEBUGGING_NOT_IMPLEMENTED)
iterations = std::min(iterations, 10);
operations = threads * iterations;
EXPECT_EQ(RunTestWithInvariantDebugging(&TestMu, threads, iterations,
operations, CheckSumG0G1),
operations);
#endif
}
TEST_P(MutexVariableThreadCountTest, Try) {
int threads = GetParam();
int iterations = 1000000 / threads;
int operations = iterations * threads;
EXPECT_EQ(RunTest(&TestTry, threads, iterations, operations), operations);
#if !defined(ABSL_MUTEX_ENABLE_INVARIANT_DEBUGGING_NOT_IMPLEMENTED)
iterations = std::min(iterations, 10);
operations = threads * iterations;
EXPECT_EQ(RunTestWithInvariantDebugging(&TestTry, threads, iterations,
operations, CheckSumG0G1),
operations);
#endif
}
TEST_P(MutexVariableThreadCountTest, R20ms) {
int threads = GetParam();
int iterations = 100;
int operations = iterations * threads;
EXPECT_EQ(RunTest(&TestR20ms, threads, iterations, operations), 0);
}
TEST_P(MutexVariableThreadCountTest, RW) {
int threads = GetParam();
int iterations = ScaleIterations(20000000) / threads;
int operations = iterations * threads;
EXPECT_EQ(RunTest(&TestRW, threads, iterations, operations), operations / 2);
#if !defined(ABSL_MUTEX_ENABLE_INVARIANT_DEBUGGING_NOT_IMPLEMENTED)
iterations = std::min(iterations, 10);
operations = threads * iterations;
EXPECT_EQ(RunTestWithInvariantDebugging(&TestRW, threads, iterations,
operations, CheckSumG0G1),
operations / 2);
#endif
}
TEST_P(MutexVariableThreadCountTest, Await) {
int threads = GetParam();
int iterations = ScaleIterations(500000);
int operations = iterations;
EXPECT_EQ(RunTest(&TestAwait, threads, iterations, operations), operations);
}
TEST_P(MutexVariableThreadCountTest, SignalAll) {
int threads = GetParam();
int iterations = 200000 / threads;
int operations = iterations;
EXPECT_EQ(RunTest(&TestSignalAll, threads, iterations, operations),
operations);
}
TEST(Mutex, Signal) {
int threads = 2; // TestSignal must use two threads
int iterations = 200000;
int operations = iterations;
EXPECT_EQ(RunTest(&TestSignal, threads, iterations, operations), operations);
}
TEST(Mutex, Timed) {
int threads = 10; // Use a fixed thread count of 10
int iterations = 1000;
int operations = iterations;
EXPECT_EQ(RunTest(&TestCVTimeout, threads, iterations, operations),
operations);
}
TEST(Mutex, CVTime) {
int threads = 10; // Use a fixed thread count of 10
int iterations = 1;
EXPECT_EQ(RunTest(&TestCVTime, threads, iterations, 1),
threads * iterations);
}
TEST(Mutex, MuTime) {
int threads = 10; // Use a fixed thread count of 10
int iterations = 1;
EXPECT_EQ(RunTest(&TestMuTime, threads, iterations, 1), threads * iterations);
}
} // namespace