Reland of Added GetCpuTime to base/ to get total CPU time consumed by process for perf tests.
BUG=webrtc:7095
Review-Url: https://codereview.webrtc.org/2695743003
Cr-Commit-Position: refs/heads/master@{#16665}
Committed: https://chromium.googlesource.com/external/webrtc/+/3ff474b72ba1b34027e8391b1014c2838af445d4
patch from issue 2695743003 at patchset 440001 (http://crrev.com/2695743003#ps440001)
Review-Url: https://codereview.webrtc.org/2706823002
Cr-Commit-Position: refs/heads/master@{#16736}
diff --git a/webrtc/base/cpu_time_unittest.cc b/webrtc/base/cpu_time_unittest.cc
new file mode 100644
index 0000000..cb025ea
--- /dev/null
+++ b/webrtc/base/cpu_time_unittest.cc
@@ -0,0 +1,108 @@
+/*
+ * Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
+ *
+ * Use of this source code is governed by a BSD-style license
+ * that can be found in the LICENSE file in the root of the source
+ * tree. An additional intellectual property rights grant can be found
+ * in the file PATENTS. All contributing project authors may
+ * be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include <memory>
+#include <algorithm>
+#include "webrtc/base/cpu_time.h"
+#include "webrtc/base/platform_thread.h"
+#include "webrtc/base/timeutils.h"
+#include "webrtc/test/gtest.h"
+#include "webrtc/system_wrappers/include/cpu_info.h"
+
+namespace {
+const int kAllowedErrorMillisecs = 30;
+const int kProcessingTimeMillisecs = 300;
+
+// Consumes approximately kProcessingTimeMillisecs of CPU time.
+bool WorkingFunction(void* counter_pointer) {
+ int64_t* counter = reinterpret_cast<int64_t*>(counter_pointer);
+ *counter = 0;
+ int64_t stop_time = rtc::SystemTimeNanos() +
+ kProcessingTimeMillisecs * rtc::kNumNanosecsPerMillisec;
+ while (rtc::SystemTimeNanos() < stop_time) {
+ (*counter)++;
+ }
+ return false;
+}
+} // namespace
+
+namespace rtc {
+
+TEST(GetProcessCpuTimeTest, SingleThread) {
+ int64_t start_time_nanos = GetProcessCpuTimeNanos();
+ int64_t counter;
+ WorkingFunction(reinterpret_cast<void*>(&counter));
+ EXPECT_GT(counter, 0);
+ int64_t duration_nanos = GetProcessCpuTimeNanos() - start_time_nanos;
+ // Should be about kProcessingTimeMillisecs.
+ EXPECT_NEAR(duration_nanos,
+ kProcessingTimeMillisecs * kNumNanosecsPerMillisec,
+ kAllowedErrorMillisecs * kNumNanosecsPerMillisec);
+}
+
+TEST(GetProcessCpuTimeTest, TwoThreads) {
+ int64_t start_time_nanos = GetProcessCpuTimeNanos();
+ int64_t counter1;
+ int64_t counter2;
+ PlatformThread thread1(WorkingFunction, reinterpret_cast<void*>(&counter1),
+ "Thread1");
+ PlatformThread thread2(WorkingFunction, reinterpret_cast<void*>(&counter2),
+ "Thread2");
+ thread1.Start();
+ thread2.Start();
+ thread1.Stop();
+ thread2.Stop();
+
+ EXPECT_GE(counter1, 0);
+ EXPECT_GE(counter2, 0);
+ int64_t duration_nanos = GetProcessCpuTimeNanos() - start_time_nanos;
+ const uint32_t kWorkingThreads = 2;
+ uint32_t used_cores =
+ std::min(webrtc::CpuInfo::DetectNumberOfCores(), kWorkingThreads);
+ // Two working threads for kProcessingTimeMillisecs consume double CPU time
+ // if there are at least 2 cores.
+ EXPECT_NEAR(duration_nanos,
+ used_cores * kProcessingTimeMillisecs * kNumNanosecsPerMillisec,
+ used_cores * kAllowedErrorMillisecs * kNumNanosecsPerMillisec);
+}
+
+TEST(GetThreadCpuTimeTest, SingleThread) {
+ int64_t start_times_nanos = GetThreadCpuTimeNanos();
+ int64_t counter;
+ WorkingFunction(reinterpret_cast<void*>(&counter));
+ EXPECT_GT(counter, 0);
+ int64_t duration_nanos = GetThreadCpuTimeNanos() - start_times_nanos;
+ EXPECT_NEAR(duration_nanos,
+ kProcessingTimeMillisecs * kNumNanosecsPerMillisec,
+ kAllowedErrorMillisecs * kNumNanosecsPerMillisec);
+}
+
+TEST(GetThreadCpuTimeTest, TwoThreads) {
+ int64_t start_time_nanos = GetThreadCpuTimeNanos();
+ int64_t counter1;
+ int64_t counter2;
+ PlatformThread thread1(WorkingFunction, reinterpret_cast<void*>(&counter1),
+ "Thread1");
+ PlatformThread thread2(WorkingFunction, reinterpret_cast<void*>(&counter2),
+ "Thread2");
+ thread1.Start();
+ thread2.Start();
+ thread1.Stop();
+ thread2.Stop();
+
+ EXPECT_GE(counter1, 0);
+ EXPECT_GE(counter2, 0);
+ int64_t duration_nanos = GetThreadCpuTimeNanos() - start_time_nanos;
+ // This thread didn't do any work.
+ EXPECT_NEAR(duration_nanos, 0,
+ kAllowedErrorMillisecs * kNumNanosecsPerMillisec);
+}
+
+} // namespace rtc
