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Merge pull request #1342 from siliceum/fix/1337-respect-max-sample-rate

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Fix #1337 : On Linux respect max sample rate
This commit is contained in:
Bartosz Taudul
2026-04-20 19:33:14 +02:00
committed by GitHub
parent 4e670fcaf5 cb9ef7814e
commit 25f09bee2c
1 changed files with 20 additions and 11 deletions
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31
public/client/TracySysTrace.cpp
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@@ -34,9 +34,9 @@ static int GetSamplingFrequency()
#endif
}
static int GetSamplingPeriod()
static int SamplingFrequencyToPeriodNs( int samplingHz )
{
return 1000000000 / GetSamplingFrequency();
return 1000000000 / samplingHz;
}
}
@@ -174,11 +174,6 @@ void WINAPI EventRecordCallback( PEVENT_RECORD record )
}
}
static int GetSamplingInterval()
{
return GetSamplingPeriod() / 100;
}
static etw::Session session_kernel = {};
static etw::Session session_vsync = {};
static PROCESSTRACE_HANDLE consumer_kernel = INVALID_PROCESSTRACE_HANDLE;
@@ -207,10 +202,10 @@ bool SysTraceStart( int64_t& samplingPeriod )
#ifndef TRACY_NO_SAMPLING
int microseconds = GetSamplingInterval() / 10;
samplingPeriod = SamplingFrequencyToPeriodNs( GetSamplingFrequency() );
const int microseconds = samplingPeriod / 1000;
if( etw::EnableCPUProfiling( session_kernel, microseconds ) != ERROR_SUCCESS )
return etw::StopSession( session_kernel ), false;
samplingPeriod = GetSamplingPeriod();
#endif
consumer_kernel = etw::SetupEventConsumer( session_kernel, EventRecordCallback );
@@ -659,7 +654,21 @@ bool SysTraceStart( int64_t& samplingPeriod )
const bool noVsync = noVsyncEnv && noVsyncEnv[0] == '1';
#endif
samplingPeriod = GetSamplingPeriod();
int samplingFrequency = GetSamplingFrequency();
if( samplingFrequency > 0 )
{
const auto maxSampleRateStr = ReadFile( "/proc/sys/kernel/perf_event_max_sample_rate" );
if( maxSampleRateStr )
{
const int sysMax = atoi( maxSampleRateStr );
if( sysMax > 0 && sysMax < samplingFrequency )
{
TracyDebug( "Requested sampling frequency %d Hz is higher than system maximum of %d Hz, reducing to system maximum.", samplingFrequency, sysMax );
samplingFrequency = sysMax;
}
}
}
samplingPeriod = SamplingFrequencyToPeriodNs( samplingFrequency );
uint32_t currentPid = ___tracy_magic_pid_override != 0 ? ___tracy_magic_pid_override : (uint32_t)getpid();
s_numCpus = (int)std::thread::hardware_concurrency();
@@ -680,7 +689,7 @@ bool SysTraceStart( int64_t& samplingPeriod )
pe.type = PERF_TYPE_SOFTWARE;
pe.size = sizeof( perf_event_attr );
pe.config = PERF_COUNT_SW_CPU_CLOCK;
pe.sample_freq = GetSamplingFrequency();
pe.sample_freq = samplingFrequency;
pe.sample_type = PERF_SAMPLE_TID | PERF_SAMPLE_TIME | PERF_SAMPLE_CALLCHAIN;
#if LINUX_VERSION_CODE >= KERNEL_VERSION( 4, 8, 0 )
pe.sample_max_stack = 127;