Added GetCpuTime to base/ to get total CPU time consumed by process for perf tests.

webrtc/base/cpu_time.cc

+/*
+ *  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.
+ */
+
+#if defined(WEBRTC_LINUX)
+#include <time.h>
+#elif defined(WEBRTC_MAC)
+#include <sys/resource.h>
+#include <sys/types.h>
+#include <sys/times.h>
+#include <mach/thread_info.h>
+#include <mach/thread_act.h>
+#include <mach/mach_init.h>
+#include <unistd.h>
+#elif defined(WEBRTC_WIN)
+#include <windows.h>
+#endif

[sprang_webrtc, 2017/02/16 12:20:18]

At this point this file isn't overly large, but I still think it could be wort
splitting this up into platform dependent .cc files and have gn pick the correct
one to build. The fewer #ifdef's the better, imo.

wdyt?

[ilnik, 2017/02/16 12:38:54]

I think file is not big enough to do it.

+
+#include "webrtc/base/cpu_time.h"
+#include "webrtc/base/logging.h"
+#include "webrtc/base/timeutils.h"
+
+#if defined(WEBRTC_WIN)
+namespace {
+//  FILETIME resolution is 100 nanosecs.
+const int64_t kNanosecsPerFiletime = 100;
+}  // namespace
+#endif
+
+namespace rtc {
+
+int64_t GetProcessCpuTime() {
+#if defined(WEBRTC_LINUX)
+  struct timespec ts;
+  if (clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &ts) == 0) {
+    return ts.tv_sec * kNumNanosecsPerSec + ts.tv_nsec;
+  } else {
+    LOG_ERR(LS_ERROR) << "clock_gettime() failed.";

[sprang_webrtc, 2017/02/16 12:20:18]

I've not seen the LOG_ERR macro before. Is it to specifically log to stderr? Why
not plain LOG(LS_ERROR) here and below?

[nisse-webrtc, 2017/02/16 12:25:03]

I suggested using LOG_ERR. The difference to plain LOG is that it displays the
errno value and/or the corresponding string. (At least according to the docs, I
haven't really used it myself).

+  }
+#elif defined(WEBRTC_MAC)
+  struct rusage rusage;
+  if (getrusage(RUSAGE_SELF, &rusage) == 0) {
+    return rusage.ru_utime.tv_sec * kNumNanosecsPerSec +
+           rusage.ru_utime.tv_usec * kNumNanosecsPerMicrosec;
+  } else {
+    LOG_ERR(LS_ERROR) << "getrusage() failed.";
+  }
+#elif defined(WEBRTC_WIN)
+  FILETIME createTime;
+  FILETIME exitTime;
+  FILETIME kernelTime;
+  FILETIME userTime;
+  if (GetProcessTimes(GetCurrentProcess(), &createTime, &exitTime, &kernelTime,
+                      &userTime) != 0) {
+    return ((static_cast<uint64_t>(userTime.dwHighDateTime) << 32) +
+            userTime.dwLowDateTime) *
+           kNanosecsPerFiletime;
+  } else {
+    LOG_ERR(LS_ERROR) << "GetProcessTimes() failed.";
+  }
+#else
+  LOG(LS_ERROR) << "No function to get CPU time";

[sprang_webrtc, 2017/02/16 12:20:18]

Is there any non-supported platform? Maybe we should just do an
RTC_NOT_REACHED(); instead?

[ilnik, 2017/02/16 12:38:54]

Done.

+#endif
+  return -1;
+}
+
+int64_t GetThreadCpuTime() {
+#if defined(WEBRTC_LINUX)
+  struct timespec ts;
+  if (clock_gettime(CLOCK_THREAD_CPUTIME_ID, &ts) == 0) {
+    return ts.tv_sec * kNumNanosecsPerSec + ts.tv_nsec;
+  } else {
+    LOG_ERR(LS_ERROR) << "clock_gettime() failed.";
+  }
+#elif defined(WEBRTC_MAC)
+  thread_basic_info_data_t info;
+  mach_msg_type_number_t count = THREAD_BASIC_INFO_COUNT;
+  if (thread_info(mach_thread_self(), THREAD_BASIC_INFO, (thread_info_t)&info,
+                  &count) == KERN_SUCCESS) {
+    return info.user_time.seconds * kNumNanosecsPerSec +
+           info.user_time.microseconds * kNumNanosecsPerMicrosec;
+  } else {
+    LOG_ERR(LS_ERROR) << "thread_info() failed.";
+  }
+#elif defined(WEBRTC_WIN)
+  FILETIME createTime;
+  FILETIME exitTime;
+  FILETIME kernelTime;
+  FILETIME userTime;
+  if (GetThreadTimes(GetCurrentThread(), &createTime, &exitTime, &kernelTime,
+                     &userTime) != 0) {
+    return ((static_cast<uint64_t>(userTime.dwHighDateTime) << 32) +
+            userTime.dwLowDateTime) *
+           kNanosecsPerFiletime;
+  } else {
+    LOG_ERR(LS_ERROR) << "GetProcessTimes() failed.";
+  }
+#else
+  LOG(LS_ERROR) << "No function to get CPU time";
+#endif
+  return -1;
+}
+
+}  // namespace rtc