On Tue, May 14, 2013 at 07:13:53PM +0900, Namhyung Kim wrote: > From: Namhyung Kim <namhyung....@lge.com> > > The ftrace record command is for saving raw ftrace buffer contents > which can be get from per_cpu/cpuX/trace_pipe_raw. > > Since ftrace events are generated very frequently so single thread for > recording mostly resulted in buffer overruns. Thus it uses per-cpu > recorder thread to prevent such cases and they save the contents to > their own files. > > These per-cpu data files are saved in a directory so that they can be > easily found when needed. I chose the default directory name as > "perf.data.dir" and the first two (i.e. "perf.data") can be changed > with -o option. The structure of the directory looks like: > > $ tree perf.data.dir > perf.data.dir/ > |-- perf.header > |-- trace-cpu0.buf > |-- trace-cpu1.buf > |-- trace-cpu2.buf > `-- trace-cpu3.buf > > In addition to trace-cpuX.buf files, it has perf.header file also. > The perf.header file is compatible with existing perf.data format and > contains usual event information, feature mask and sample data. The > sample data is synthesized to indicate given cpu has a record file.
so AFAICS we store sample event for each cpu we recorded (in record command) and by processing those samples (show/report) we get data files names for each cpu hum, I might have missed some discussion about this, but seems like header feature fits better for this, as long as we store only cpus.. FTRACE_CPUS or something like thius with simple array or if we are going to use event, maybe user event via enum perf_user_event_type fits better jirka -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
