Revert of [Reland] Implement CPU time for OS X and POSIX. (patchset #1 id:1 of...

Revert of [Reland] Implement CPU time for OS X and POSIX. (patchset #1 id:1 of https://codereview.chromium.org/1966183003/ )

Reason for revert:
Blocks roll: https://codereview.chromium.org/1972303002/

Original issue's description:
> [Reland] Implement CPU time for OS X and POSIX.
>
> V8 tracing controller uses 2 clocks: wall clock and cpu clock. This patch
> implements CPU time for OS X and POSIX to provide more accurate
> accounting of CPU time used by each thread.
>
> BUG=v8:4984
> LOG=n
>
> Committed: https://crrev.com/efa27fb25e1fa5b8465f4af710086b73b0cba660
> Cr-Commit-Position: refs/heads/master@{#36213}

TBR=fmeawad@chromium.org,jochen@chromium.org,rsesek@chromium.org,bmeurer@chromium.org,lpy@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:4984

Review-Url: https://codereview.chromium.org/1977753002
Cr-Commit-Position: refs/heads/master@{#36225}

src/base/platform/time.cc

@@ -10,9 +10,7 @@
 #include <unistd.h>
 #endif
 #if V8_OS_MACOSX
-#include <mach/mach.h>
 #include <mach/mach_time.h>
-#include <pthread.h>
 #endif
 
 #include <cstring>
@@ -27,51 +25,6 @@
 #include "src/base/logging.h"
 #include "src/base/platform/platform.h"
 
-namespace {
-
-#if V8_OS_MACOSX
-int64_t ComputeThreadTicks() {
-  mach_msg_type_number_t thread_info_count = THREAD_BASIC_INFO_COUNT;
-  thread_basic_info_data_t thread_info_data;
-  kern_return_t kr = thread_info(
-      pthread_mach_thread_np(pthread_self()),
-      THREAD_BASIC_INFO,
-      reinterpret_cast<thread_info_t>(&thread_info_data),
-      &thread_info_count);
-  CHECK(kr == KERN_SUCCESS);
-
-  v8::base::CheckedNumeric<int64_t> absolute_micros(
-      thread_info_data.user_time.seconds);
-  absolute_micros *= v8::base::Time::kMicrosecondsPerSecond;
-  absolute_micros += thread_info_data.user_time.microseconds;
-  return absolute_micros.ValueOrDie();
-}
-#elif V8_OS_POSIX
-// Helper function to get results from clock_gettime() and convert to a
-// microsecond timebase. Minimum requirement is MONOTONIC_CLOCK to be supported
-// on the system. FreeBSD 6 has CLOCK_MONOTONIC but defines
-// _POSIX_MONOTONIC_CLOCK to -1.
-inline int64_t ClockNow(clockid_t clk_id) {
-#if (defined(_POSIX_MONOTONIC_CLOCK) && _POSIX_MONOTONIC_CLOCK >= 0) || \
-  defined(V8_OS_BSD) || defined(V8_OS_ANDROID)
-  struct timespec ts;
-  if (clock_gettime(clk_id, &ts) != 0) {
-    UNREACHABLE();
-    return 0;
-  }
-  v8::base::internal::CheckedNumeric<int64_t> result(ts.tv_sec);
-  result *= v8::base::Time::kMicrosecondsPerSecond;
-  result += (ts.tv_nsec / v8::base::Time::kNanosecondsPerMicrosecond);
-  return result.ValueOrDie();
-#else  // Monotonic clock not supported.
-  return 0;
-#endif
-}
-#endif  // V8_OS_MACOSX
-
-
-}  // namespace
-
 namespace v8 {
 namespace base {
 
@@ -588,7 +541,12 @@ TimeTicks TimeTicks::HighResolutionNow() {
 #elif V8_OS_SOLARIS
   ticks = (gethrtime() / Time::kNanosecondsPerMicrosecond);
 #elif V8_OS_POSIX
-  ticks = ClockNow(CLOCK_MONOTONIC);
+  struct timespec ts;
+  int result = clock_gettime(CLOCK_MONOTONIC, &ts);
+  DCHECK_EQ(0, result);
+  USE(result);
+  ticks = (ts.tv_sec * Time::kMicrosecondsPerSecond +
+           ts.tv_nsec / Time::kNanosecondsPerMicrosecond);
 #endif  // V8_OS_MACOSX
   // Make sure we never return 0 here.
   return TimeTicks(ticks + 1);
@@ -602,30 +560,5 @@ bool TimeTicks::IsHighResolutionClockWorking() {
 
 #endif  // V8_OS_WIN
 
-
-// TODO(lpy): For windows ThreadTicks implementation,
-// see http://crbug.com/v8/5000
-bool ThreadTicks::IsSupported() {
-#if (defined(_POSIX_THREAD_CPUTIME) && (_POSIX_THREAD_CPUTIME >= 0)) || \
-    defined(V8_OS_MACOSX) || defined(V8_OS_ANDROID)
-    return true;
-#else
-    return false;
-#endif
-}
-
-
-ThreadTicks ThreadTicks::Now() {
-#if V8_OS_MACOSX
-  return ThreadTicks(ComputeThreadTicks());
-#elif(defined(_POSIX_THREAD_CPUTIME) && (_POSIX_THREAD_CPUTIME >= 0)) || \
-  defined(V8_OS_ANDROID)
-  return ThreadTicks(ClockNow(CLOCK_THREAD_CPUTIME_ID));
-#else
-  UNREACHABLE();
-  return ThreadTicks();
-#endif
-}
-
 }  // namespace base
 }  // namespace v8

src/base/platform/time.h

@@ -360,7 +360,7 @@ class TimeTicks final : public time_internal::TimeBase<TimeTicks> {
   friend class time_internal::TimeBase<TimeTicks>;
 
   // Please use Now() to create a new object. This is for internal use
-  // and testing. Ticks are in microseconds.
+  // and testing. Ticks is in microseconds.
   explicit TimeTicks(int64_t ticks) : TimeBase(ticks) {}
 };
 
@@ -368,31 +368,6 @@ inline TimeTicks operator+(const TimeDelta& delta, const TimeTicks& ticks) {
   return ticks + delta;
 }
 
-
-// ThreadTicks ----------------------------------------------------------------
-
-// Represents a clock, specific to a particular thread, than runs only while the
-// thread is running.
-class ThreadTicks final : public time_internal::TimeBase<ThreadTicks> {
- public:
-  ThreadTicks() : TimeBase(0) {}
-
-  // Returns true if ThreadTicks::Now() is supported on this system.
-  static bool IsSupported();
-
-  // Returns thread-specific CPU-time on systems that support this feature.
-  // Needs to be guarded with a call to IsSupported(). Use this timer
-  // to (approximately) measure how much time the calling thread spent doing
-  // actual work vs. being de-scheduled. May return bogus results if the thread
-  // migrates to another CPU between two calls. Returns an empty ThreadTicks
-  // object until the initialization is completed.
-  static ThreadTicks Now();
-
- private:
-  // This is for internal use and testing. Ticks are in microseconds.
-  explicit ThreadTicks(int64_t ticks) : TimeBase(ticks) {}
-};
-
 }  // namespace base
 }  // namespace v8
 

test/unittests/base/platform/time-unittest.cc

@@ -16,7 +16,6 @@
 #endif
 
 #include "src/base/platform/elapsed-timer.h"
-#include "src/base/platform/platform.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace v8 {
@@ -183,32 +182,5 @@ TEST(TimeTicks, IsMonotonic) {
   }
 }
 
-
-// Disable on windows until it is implemented.
-#if V8_OS_ANDROID || V8_OS_WIN
-#define MAYBE_ThreadNow DISABLED_ThreadNow
-#else
-#define MAYBE_ThreadNow ThreadNow
-#endif
-TEST(ThreadTicks, MAYBE_ThreadNow) {
-  if (ThreadTicks::IsSupported()) {
-    TimeTicks begin = TimeTicks::Now();
-    ThreadTicks begin_thread = ThreadTicks::Now();
-    // Make sure that ThreadNow value is non-zero.
-    EXPECT_GT(begin_thread, ThreadTicks());
-    // Sleep for 10 milliseconds to get the thread de-scheduled.
-    OS::Sleep(base::TimeDelta::FromMilliseconds(10));
-    ThreadTicks end_thread = ThreadTicks::Now();
-    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);
-  }
-}
-
 }  // namespace base
 }  // namespace v8