celeritas::TracingSession Class Reference

Record Perfetto events during the lifetime of this object. More...

#include <TracingSession.hh>

Classes
struct	Impl

Public Member Functions
	TracingSession ()
	Start a system tracing session.
	TracingSession (std::string const &filename)
	Start an in-process tracing session.
void	start () noexcept
	The session is now started on construction; this is now a null-op.
	operator bool () const
	Return whether profiling is enabled.

Static Public Member Functions
static void	flush () noexcept
	Flush profiling events associated with the calling thread.

Detailed Description

Record Perfetto events during the lifetime of this object.

This RAII class manages a Perfetto tracing session. Only a single tracing mode is supported. If you are only interested in application-level events (ScopedProfiling and trace_counter), then the in-process mode is sufficient and is enabled by providing the trace data filename to the constructor. When using in-process tracing, the buffer size can be configured by setting CELER_PERFETTO_BUFFER_SIZE_MB.

If no filename is provided, start a system tracing session which records both application-level events and kernel events. Root privilege and Linux ftrace https://kernel.org/doc/Documentation/trace/ftrace.txt are required. To start the system daemons using the perfetto backend, see https://perfetto.dev/docs/quickstart/linux-tracing#capturing-a-trace

Note

Profiling is disabled unless the CELER_ENABLE_PROFILING environment variable is set; see celeritas::ScopedProfiling.

Member Function Documentation

flush()

void celeritas::TracingSession::flush ( )

inlinestaticnoexcept

Flush profiling events associated with the calling thread.

In multi-threaded applications, this should be called from each worker thread to ensure that their track events are correctly written.

This is used by the Geant4 interface class LocalTransporter which may not have access to the session instance.

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The documentation for this class was generated from the following files:

• TracingSession.hh
• TracingSession.perfetto.cc