Implement thread-specific CPU time on Mac OS X

This is different from https://code.google.com/p/chromium/codesearch#chromium/src/base/process/process_metrics_mac.cc&l=216 as it gets the per-thread CPU time while process metrics gets all-thread CPU usage.

BUG=280744

Review URL: https://codereview.chromium.org/56973012

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@233450 0039d316-1c4b-4281-b951-d872f2087c98

base/time/time.h

@@ -548,7 +548,8 @@ class BASE_EXPORT TimeTicks {
 
   // Returns true if ThreadNow() is supported on this system.
   static bool IsThreadNowSupported() {
-#if defined(_POSIX_THREAD_CPUTIME) && (_POSIX_THREAD_CPUTIME >= 0)
+#if (defined(_POSIX_THREAD_CPUTIME) && (_POSIX_THREAD_CPUTIME >= 0)) || \
+    (defined(OS_MACOSX) && !defined(OS_IOS))
     return true;
 #else
     return false;

base/time/time_mac.cc

@@ -6,6 +6,7 @@
 
 #include <CoreFoundation/CFDate.h>
 #include <CoreFoundation/CFTimeZone.h>
+#include <mach/mach.h>
 #include <mach/mach_time.h>
 #include <sys/sysctl.h>
 #include <sys/time.h>
@@ -15,6 +16,7 @@
 #include "base/basictypes.h"
 #include "base/logging.h"
 #include "base/mac/scoped_cftyperef.h"
+#include "base/mac/scoped_mach_port.h"
 
 namespace {
 
@@ -64,6 +66,33 @@ uint64_t ComputeCurrentTicks() {
 #endif  // defined(OS_IOS)
 }
 
+uint64_t ComputeThreadTicks() {
+#if defined(OS_IOS)
+  NOTREACHED();
+  return 0;
+#else
+  base::mac::ScopedMachPort thread(mach_thread_self());
+  mach_msg_type_number_t thread_info_count = THREAD_BASIC_INFO_COUNT;
+  thread_basic_info_data_t thread_info_data;
+
+  if (thread == MACH_PORT_NULL) {
+    DLOG(ERROR) << "Failed to get mach_thread_self()";
+    return 0;
+  }
+
+  kern_return_t kr = thread_info(
+      thread,
+      THREAD_BASIC_INFO,
+      reinterpret_cast<thread_info_t>(&thread_info_data),
+      &thread_info_count);
+  DCHECK_EQ(KERN_SUCCESS, kr);
+
+  return (thread_info_data.user_time.seconds *
+              base::Time::kMicrosecondsPerSecond) +
+         thread_info_data.user_time.microseconds;
+#endif  // defined(OS_IOS)
+}
+
 }  // namespace
 
 namespace base {
@@ -196,8 +225,7 @@ bool TimeTicks::IsHighResNowFastAndReliable() {
 
 // static
 TimeTicks TimeTicks::ThreadNow() {
-  NOTREACHED();
-  return TimeTicks();
+  return TimeTicks(ComputeThreadTicks());
 }
 
 // static

base/time/time_unittest.cc

@@ -639,12 +639,17 @@ TEST(TimeTicks, ThreadNow) {
   if (TimeTicks::IsThreadNowSupported()) {
     TimeTicks begin = TimeTicks::Now();
     TimeTicks begin_thread = TimeTicks::ThreadNow();
-    // Sleep for 10 milliseconds to get the thread de-scheduled
+    // Make sure that ThreadNow value is non-zero.
+    EXPECT_GT(begin_thread, TimeTicks());
+    // Sleep for 10 milliseconds to get the thread de-scheduled.
     base::PlatformThread::Sleep(base::TimeDelta::FromMilliseconds(10));
     TimeTicks end_thread = TimeTicks::ThreadNow();
     TimeTicks end = TimeTicks::Now();
     TimeDelta delta = end - begin;
     TimeDelta delta_thread = end_thread - begin_thread;
+    // Make sure that some thread time have elapsed.
+    EXPECT_GT(delta_thread.InMicroseconds(), 0);
+    // But the thread time is at least 9ms less than clock time.
     TimeDelta difference = delta - delta_thread;
     EXPECT_GE(difference.InMicroseconds(), 9000);
   }