PerfProfile Struct Reference

Algorithm to enable/disable profiling with Linux perf at given events. More...

Inheritance diagram for PerfProfile:

Collaboration diagram for PerfProfile:

Public Member Functions
StatusCode	initialize () override
StatusCode	finalize () override
void	operator() () const override

Private Member Functions
void	fifo_write (std::string_view s) const

Private Attributes
std::atomic< long unsigned >	m_eventNumber = 0
int	m_fifo = -1
Gaudi::Property< std::string >	m_fifoPath { this, "FIFOPath", "GaudiPerfProfile.fifo", "Path to perf control FIFO." }
Gaudi::Property< unsigned long >	m_nStartFromEvent
Gaudi::Property< unsigned long >	m_nStopAtEvent

Detailed Description

Algorithm to enable/disable profiling with Linux perf at given events.

Needs at least perf 5.9. To control perf record, start it as

perf record -D -1 –control fifo:GaudiPerfProfile.fifo ... gaudirun.py ...

The path to the control fifo (GaudiPerfProfile.fifo) is configurable with the FIFOPath property. The fifo must be created before running perf.

Definition at line 26 of file PerfProfile.cpp.

Member Function Documentation

fifo_write()

void PerfProfile::fifo_write ( std::string_view  s ) const

inlineprivate

Definition at line 61 of file PerfProfile.cpp.

                                            {
    if ( ::write( m_fifo, s.data(), s.size() ) < ssize_t( s.size() ) ) {
      error() << "Write of \"" << s << "\" to FIFO failed: " << ::strerror( errno ) << endmsg;
    }
  }

finalize()

StatusCode PerfProfile::finalize ( )

inlineoverride

Definition at line 40 of file PerfProfile.cpp.

                                 {
    if ( m_fifo != -1 ) { ::close( m_fifo ); }
    return Consumer::finalize();
  }

initialize()

StatusCode PerfProfile::initialize ( )

inlineoverride

Definition at line 29 of file PerfProfile.cpp.

                                   {
    return Consumer::initialize().andThen( [this]() {
      m_fifo = ::open( m_fifoPath.value().c_str(), O_WRONLY | O_NONBLOCK );
      if ( m_fifo == -1 ) {
        fatal() << "open(\"" << m_fifoPath.value() << "\"): " << ::strerror( errno ) << endmsg;
        return StatusCode::FAILURE;
      }
      return StatusCode::SUCCESS;
    } );
  }

operator()()

void PerfProfile::operator() ( ) const

inlineoverride

Definition at line 45 of file PerfProfile.cpp.

                                   {
    // We could use EventContext::evt(), however it is not always valid, as is the case with EvtSel="NONE". Instead, use
    // an atomic counter.
    auto eventNumber = m_eventNumber++;
    if ( eventNumber == m_nStartFromEvent.value() ) {
      warning() << "Starting perf profile at event " << eventNumber << endmsg;
      fifo_write( "enable\n" );
    }
 
    if ( m_nStopAtEvent > 0 && eventNumber == m_nStopAtEvent.value() ) {
      warning() << "Stopping perf profile at event " << eventNumber << endmsg;
      fifo_write( "disable\n" );
    }
  }

Member Data Documentation

m_eventNumber

std::atomic<long unsigned> PerfProfile::m_eventNumber = 0

mutableprivate

Definition at line 67 of file PerfProfile.cpp.

m_fifo

int PerfProfile::m_fifo = -1

private

Definition at line 68 of file PerfProfile.cpp.

m_fifoPath

Gaudi::Property<std::string> PerfProfile::m_fifoPath { this, "FIFOPath", "GaudiPerfProfile.fifo", "Path to perf control FIFO." }

private

Definition at line 70 of file PerfProfile.cpp.

m_nStartFromEvent

Gaudi::Property<unsigned long> PerfProfile::m_nStartFromEvent

private

Initial value:

{ this, "StartFromEventN", 1,
                                                    "After what event we start profiling." }

Definition at line 71 of file PerfProfile.cpp.

m_nStopAtEvent

Gaudi::Property<unsigned long> PerfProfile::m_nStopAtEvent

private

Initial value:

{
      this, "StopAtEventN", 0,
      "After what event we stop profiling. If 0 than we also profile finalization stage. Default = 0." }

Definition at line 73 of file PerfProfile.cpp.

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The documentation for this struct was generated from the following file:

• GaudiProfiling/src/component/perf/PerfProfile.cpp