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// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include <windows.h>
#include <mmsystem.h>
#include <process.h>
#include "base/threading/platform_thread.h"
#include "base/time.h"
#include "testing/gtest/include/gtest/gtest.h"
using base::Time;
using base::TimeDelta;
using base::TimeTicks;
namespace {
class MockTimeTicks : public TimeTicks {
public:
static DWORD Ticker() {
return static_cast<int>(InterlockedIncrement(&ticker_));
}
static void InstallTicker() {
old_tick_function_ = SetMockTickFunction(&Ticker);
ticker_ = -5;
}
static void UninstallTicker() {
SetMockTickFunction(old_tick_function_);
}
private:
static volatile LONG ticker_;
static TickFunctionType old_tick_function_;
};
volatile LONG MockTimeTicks::ticker_;
MockTimeTicks::TickFunctionType MockTimeTicks::old_tick_function_;
HANDLE g_rollover_test_start;
unsigned __stdcall RolloverTestThreadMain(void* param) {
int64 counter = reinterpret_cast<int64>(param);
DWORD rv = WaitForSingleObject(g_rollover_test_start, INFINITE);
EXPECT_EQ(rv, WAIT_OBJECT_0);
TimeTicks last = TimeTicks::Now();
for (int index = 0; index < counter; index++) {
TimeTicks now = TimeTicks::Now();
int64 milliseconds = (now - last).InMilliseconds();
// This is a tight loop; we could have looped faster than our
// measurements, so the time might be 0 millis.
EXPECT_GE(milliseconds, 0);
EXPECT_LT(milliseconds, 250);
last = now;
}
return 0;
}
} // namespace
TEST(TimeTicks, WinRollover) {
// The internal counter rolls over at ~49days. We'll use a mock
// timer to test this case.
// Basic test algorithm:
// 1) Set clock to rollover - N
// 2) Create N threads
// 3) Start the threads
// 4) Each thread loops through TimeTicks() N times
// 5) Each thread verifies integrity of result.
const int kThreads = 8;
// Use int64 so we can cast into a void* without a compiler warning.
const int64 kChecks = 10;
// It takes a lot of iterations to reproduce the bug!
// (See bug 1081395)
for (int loop = 0; loop < 4096; loop++) {
// Setup
MockTimeTicks::InstallTicker();
g_rollover_test_start = CreateEvent(0, TRUE, FALSE, 0);
HANDLE threads[kThreads];
for (int index = 0; index < kThreads; index++) {
void* argument = reinterpret_cast<void*>(kChecks);
unsigned thread_id;
threads[index] = reinterpret_cast<HANDLE>(
_beginthreadex(NULL, 0, RolloverTestThreadMain, argument, 0,
&thread_id));
EXPECT_NE((HANDLE)NULL, threads[index]);
}
// Start!
SetEvent(g_rollover_test_start);
// Wait for threads to finish
for (int index = 0; index < kThreads; index++) {
DWORD rv = WaitForSingleObject(threads[index], INFINITE);
EXPECT_EQ(rv, WAIT_OBJECT_0);
}
CloseHandle(g_rollover_test_start);
// Teardown
MockTimeTicks::UninstallTicker();
}
}
TEST(TimeTicks, SubMillisecondTimers) {
// HighResNow doesn't work on some systems. Since the product still works
// even if it doesn't work, it makes this entire test questionable.
if (!TimeTicks::IsHighResClockWorking())
return;
const int kRetries = 1000;
bool saw_submillisecond_timer = false;
// Run kRetries attempts to see a sub-millisecond timer.
for (int index = 0; index < 1000; index++) {
TimeTicks last_time = TimeTicks::HighResNow();
TimeDelta delta;
// Spin until the clock has detected a change.
do {
delta = TimeTicks::HighResNow() - last_time;
} while (delta.InMicroseconds() == 0);
if (delta.InMicroseconds() < 1000) {
saw_submillisecond_timer = true;
break;
}
}
EXPECT_TRUE(saw_submillisecond_timer);
}
TEST(TimeTicks, TimeGetTimeCaps) {
// Test some basic assumptions that we expect about how timeGetDevCaps works.
TIMECAPS caps;
MMRESULT status = timeGetDevCaps(&caps, sizeof(caps));
EXPECT_EQ(TIMERR_NOERROR, status);
if (status != TIMERR_NOERROR) {
printf("Could not get timeGetDevCaps\n");
return;
}
EXPECT_GE(static_cast<int>(caps.wPeriodMin), 1);
EXPECT_GT(static_cast<int>(caps.wPeriodMax), 1);
EXPECT_GE(static_cast<int>(caps.wPeriodMin), 1);
EXPECT_GT(static_cast<int>(caps.wPeriodMax), 1);
printf("timeGetTime range is %d to %dms\n", caps.wPeriodMin,
caps.wPeriodMax);
}
TEST(TimeTicks, QueryPerformanceFrequency) {
// Test some basic assumptions that we expect about QPC.
LARGE_INTEGER frequency;
BOOL rv = QueryPerformanceFrequency(&frequency);
EXPECT_EQ(TRUE, rv);
EXPECT_GT(frequency.QuadPart, 1000000); // Expect at least 1MHz
printf("QueryPerformanceFrequency is %5.2fMHz\n",
frequency.QuadPart / 1000000.0);
}
TEST(TimeTicks, TimerPerformance) {
// Verify that various timer mechanisms can always complete quickly.
// Note: This is a somewhat arbitrary test.
const int kLoops = 10000;
// Due to the fact that these run on bbots, which are horribly slow,
// we can't really make any guarantees about minimum runtime.
// Really, we want these to finish in ~10ms, and that is generous.
const int kMaxTime = 35; // Maximum acceptible milliseconds for test.
typedef TimeTicks (*TestFunc)();
struct TestCase {
TestFunc func;
char *description;
};
// Cheating a bit here: assumes sizeof(TimeTicks) == sizeof(Time)
// in order to create a single test case list.
COMPILE_ASSERT(sizeof(TimeTicks) == sizeof(Time),
test_only_works_with_same_sizes);
TestCase cases[] = {
{ reinterpret_cast<TestFunc>(Time::Now), "Time::Now" },
{ TimeTicks::Now, "TimeTicks::Now" },
{ TimeTicks::HighResNow, "TimeTicks::HighResNow" },
{ NULL, "" }
};
int test_case = 0;
while (cases[test_case].func) {
TimeTicks start = TimeTicks::HighResNow();
for (int index = 0; index < kLoops; index++)
cases[test_case].func();
TimeTicks stop = TimeTicks::HighResNow();
// Turning off the check for acceptible delays. Without this check,
// the test really doesn't do much other than measure. But the
// measurements are still useful for testing timers on various platforms.
// The reason to remove the check is because the tests run on many
// buildbots, some of which are VMs. These machines can run horribly
// slow, and there is really no value for checking against a max timer.
//EXPECT_LT((stop - start).InMilliseconds(), kMaxTime);
printf("%s: %1.2fus per call\n", cases[test_case].description,
(stop - start).InMillisecondsF() * 1000 / kLoops);
test_case++;
}
}
TEST(TimeTicks, Drift) {
// If QPC is disabled, this isn't measuring anything.
if (!TimeTicks::IsHighResClockWorking())
return;
const int kIterations = 100;
int64 total_drift = 0;
for (int i = 0; i < kIterations; ++i) {
int64 drift_microseconds = TimeTicks::GetQPCDriftMicroseconds();
// Make sure the drift never exceeds our limit.
EXPECT_LT(drift_microseconds, 50000);
// Sleep for a few milliseconds (note that it means 1000 microseconds).
// If we check the drift too frequently, it's going to increase
// monotonically, making our measurement less realistic.
base::PlatformThread::Sleep(
base::TimeDelta::FromMilliseconds((i % 2 == 0) ? 1 : 2));
total_drift += drift_microseconds;
}
// Sanity check. We expect some time drift to occur, especially across
// the number of iterations we do.
EXPECT_LT(0, total_drift);
printf("average time drift in microseconds: %lld\n",
total_drift / kIterations);
}
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