• Jeff Hostetler's avatar
    trace2: create new combined trace facility · ee4512ed
    Jeff Hostetler authored
    Create a new unified tracing facility for git.  The eventual intent is to
    replace the current trace_printf* and trace_performance* routines with a
    unified set of git_trace2* routines.
    
    In addition to the usual printf-style API, trace2 provides higer-level
    event verbs with fixed-fields allowing structured data to be written.
    This makes post-processing and analysis easier for external tools.
    
    Trace2 defines 3 output targets.  These are set using the environment
    variables "GIT_TR2", "GIT_TR2_PERF", and "GIT_TR2_EVENT".  These may be
    set to "1" or to an absolute pathname (just like the current GIT_TRACE).
    
    * GIT_TR2 is intended to be a replacement for GIT_TRACE and logs command
      summary data.
    
    * GIT_TR2_PERF is intended as a replacement for GIT_TRACE_PERFORMANCE.
      It extends the output with columns for the command process, thread,
      repo, absolute and relative elapsed times.  It reports events for
      child process start/stop, thread start/stop, and per-thread function
      nesting.
    
    * GIT_TR2_EVENT is a new structured format. It writes event data as a
      series of JSON records.
    
    Calls to trace2 functions log to any of the 3 output targets enabled
    without the need to call different trace_printf* or trace_performance*
    routines.
    Signed-off-by: default avatarJeff Hostetler <jeffhost@microsoft.com>
    Signed-off-by: default avatarJunio C Hamano <gitster@pobox.com>
    ee4512ed
repository.h 4.43 KB