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| author | fdoray <fdoray@chromium.org> | 2015-10-14 20:46:40 -0700 |
|---|---|---|
| committer | Commit bot <commit-bot@chromium.org> | 2015-10-15 03:47:30 +0000 |
| commit | dc2a659b0ad54c3dcb632b876e40a71fa03019e9 (patch) | |
| tree | e3f3a87c7e8a03716389609435214f0be6bd87bf /gpu/perftests | |
| parent | 5d49f7978f42d05431b8ed851050ce0687938512 (diff) | |
| download | chromium_src-dc2a659b0ad54c3dcb632b876e40a71fa03019e9.zip chromium_src-dc2a659b0ad54c3dcb632b876e40a71fa03019e9.tar.gz chromium_src-dc2a659b0ad54c3dcb632b876e40a71fa03019e9.tar.bz2 | |
Implement ThreadTicks::Now on Windows.
Use QueryThreadCycleTime() to get the number of CPU clock cycles used
by the current thread. Convert it to microseconds using a measured
TSC frequency.
The value returned by QueryThreadCycleTime() is based on the rdtsc
instruction. For several years, Intel has been shipping CPUs with a
constant-rate counter, which means that the QueryThreadCycleTime()
results are directly proportional to wall-clock time on most systems
(see crbug.com/280743#c15). ThreadTicks::IsSupported() will return
false if the CPU doesn't have a constant rate TSC.
BUG=280743
CQ_INCLUDE_TRYBOTS=tryserver.blink:linux_blink_rel
Review URL: https://codereview.chromium.org/1390743002
Cr-Commit-Position: refs/heads/master@{#354213}
Diffstat (limited to 'gpu/perftests')
| -rw-r--r-- | gpu/perftests/measurements.cc | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/gpu/perftests/measurements.cc b/gpu/perftests/measurements.cc index b2dac91..645784d 100644 --- a/gpu/perftests/measurements.cc +++ b/gpu/perftests/measurements.cc @@ -57,6 +57,7 @@ MeasurementTimers::MeasurementTimers(gfx::GPUTimingClient* gpu_timing_client) DCHECK(gpu_timing_client); wall_time_start_ = base::TraceTicks::Now(); if (base::ThreadTicks::IsSupported()) { + base::ThreadTicks::WaitUntilInitialized(); cpu_time_start_ = base::ThreadTicks::Now(); } else { static bool logged_once = false; |