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/**
* Copyright (C) 2020-present MongoDB, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the Server Side Public License, version 1,
* as published by MongoDB, Inc.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* Server Side Public License for more details.
*
* You should have received a copy of the Server Side Public License
* along with this program. If not, see
* <http://www.mongodb.com/licensing/server-side-public-license>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the Server Side Public License in all respects for
* all of the code used other than as permitted herein. If you modify file(s)
* with this exception, you may extend this exception to your version of the
* file(s), but you are not obligated to do so. If you do not wish to do so,
* delete this exception statement from your version. If you delete this
* exception statement from all source files in the program, then also delete
* it in the license file.
*/
#include "mongo/db/operation_cpu_timer.h"
#include "mongo/db/service_context_test_fixture.h"
#include "mongo/logv2/log.h"
#include "mongo/platform/atomic_word.h"
#include "mongo/stdx/chrono.h"
#include "mongo/stdx/condition_variable.h"
#include "mongo/stdx/mutex.h"
#include "mongo/stdx/thread.h"
#include "mongo/unittest/barrier.h"
#include "mongo/unittest/death_test.h"
#include "mongo/unittest/unittest.h"
#include "mongo/util/duration.h"
#include "mongo/util/time_support.h"
#define MONGO_LOGV2_DEFAULT_COMPONENT ::mongo::logv2::LogComponent::kTest
namespace mongo {
class OperationCPUTimerTest : public ServiceContextTest {
public:
auto makeClient() const {
return getGlobalServiceContext()->makeClient("AlternativeClient");
}
auto getTimer() const {
return OperationCPUTimer::get(_opCtx.get());
}
void setUp() {
_opCtx = getGlobalServiceContext()->makeOperationContext(Client::getCurrent());
}
void busyWait(Nanoseconds delay) const {
AtomicWord<bool> mayJoin{false};
stdx::thread blocker([&] {
sleepFor(delay);
mayJoin.store(true);
});
while (!mayJoin.load()) {
// Busy wait for the blocker thread.
}
blocker.join();
}
private:
ServiceContext::UniqueOperationContext _opCtx;
};
#if defined(__linux__)
TEST_F(OperationCPUTimerTest, TestTimer) {
auto timer = getTimer();
timer->start();
busyWait(Microseconds(1)); // A small delay to make sure the timer advances.
ASSERT_GT(timer->getElapsed(), Nanoseconds(0));
timer->stop();
const auto elapsedAfterStop = timer->getElapsed();
busyWait(Microseconds(10)); // A relatively longer delay to ensure the timer doesn't proceed.
const auto elapsedAfterSleep = timer->getElapsed();
ASSERT_EQ(elapsedAfterStop, elapsedAfterSleep);
}
TEST_F(OperationCPUTimerTest, TestReset) {
auto timer = getTimer();
timer->start();
busyWait(Milliseconds(1)); // Introducing some delay for the timer to measure.
timer->stop();
auto elapsedAfterStop = timer->getElapsed();
ASSERT_GTE(elapsedAfterStop, Milliseconds(1));
timer->start();
auto elapsedAfterReset = timer->getElapsed();
ASSERT_LT(elapsedAfterReset, elapsedAfterStop);
}
TEST_F(OperationCPUTimerTest, TestTimerDetachAndAttachHandlers) {
unittest::Barrier failPointsReady{2};
stdx::thread observer([&] {
FailPointEnableBlock fpAttach("hangCPUTimerAfterOnThreadAttach");
{
FailPointEnableBlock fpDetach("hangCPUTimerAfterOnThreadDetach");
failPointsReady.countDownAndWait();
fpDetach->waitForTimesEntered(1);
}
fpAttach->waitForTimesEntered(1);
});
auto timer = getTimer();
timer->start();
failPointsReady.countDownAndWait();
{
auto client = makeClient();
AlternativeClientRegion acr(client);
}
timer->stop();
observer.join();
}
DEATH_TEST_F(OperationCPUTimerTest,
AccessTimerForDetachedOperation,
"Operation not attached to the current thread") {
auto client = Client::releaseCurrent();
getTimer();
}
DEATH_TEST_F(OperationCPUTimerTest, StopTimerBeforeStart, "Timer is not running") {
getTimer()->stop();
}
DEATH_TEST_F(OperationCPUTimerTest, StartTimerMultipleTimes, "Timer has already started") {
getTimer()->start();
getTimer()->start();
}
DEATH_TEST_F(OperationCPUTimerTest, OnAttachForAttachedTimer, "Timer has already been attached") {
auto timer = getTimer();
timer->start();
timer->onThreadAttach();
}
DEATH_TEST_F(OperationCPUTimerTest, OnDetachForDetachedTimer, "Timer is not attached") {
auto timer = getTimer();
timer->start();
auto client = Client::releaseCurrent();
timer->onThreadDetach();
}
DEATH_TEST_F(OperationCPUTimerTest, GetElapsedForPausedTimer, "Not attached to current thread") {
auto timer = getTimer();
timer->start();
auto client = Client::releaseCurrent();
timer->getElapsed();
}
TEST_F(OperationCPUTimerTest, TimerPausesOnBlockingSleep) {
// This test checks if the time measured by `OperationCPUTimer` does not include the period of
// time the operation was blocked (e.g., waiting on a condition variable). The idea is to have
// the operation block for `kSomeDelay`, ensure the elapsed time observed by the timer is always
// less than `kSomeDelay`, and repeat the test `kRepeats` times. To account for the sporadic
// wake ups, the test does not fail unless the number of failures exceeds `kMaxFailures`. This
// is just a best-effort, and the number of failures is not guaranteed to not exceed the upper
// bound (i.e., `kMaxFailures`).
const auto kSomeDelay = Milliseconds(1);
const auto kRepeats = 1000;
const auto kMaxFailureRate = 0.1;
const auto kMaxFailures = kMaxFailureRate * kRepeats;
auto timer = getTimer();
auto checkTimer = [&] {
auto elapsed = timer->getElapsed();
if (elapsed < kSomeDelay)
return true;
LOGV2_WARNING(5160101,
"Elapsed operation time exceeded the upper bound",
"elapsed"_attr = elapsed,
"delay"_attr = kSomeDelay);
return false;
};
auto failures = 0;
for (auto i = 0; i < kRepeats; i++) {
timer->start();
sleepFor(kSomeDelay);
if (!checkTimer())
failures++;
timer->stop();
stdx::condition_variable cv;
auto mutex = MONGO_MAKE_LATCH("TimerPausesOnBlockingSleep");
timer->start();
stdx::unique_lock lk(mutex);
cv.wait_for(lk, kSomeDelay.toSystemDuration(), [] { return false; });
if (!checkTimer())
failures++;
timer->stop();
}
ASSERT_LTE(failures, kMaxFailures);
}
#else
TEST_F(OperationCPUTimerTest, TimerNotSetIfNotSupported) {
auto timer = getTimer();
ASSERT(timer == nullptr);
}
#endif // defined(__linux__)
} // namespace mongo
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