On Fri, 19 Feb 2021 07:53:53 +0200 "Tzvetomir Stoyanov (VMware)" <tz.stoyanov@xxxxxxxxx> wrote: > Added new API for opening trace_marker file of given instance: > tracefs_trace_marker_get_fd(); > > Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@xxxxxxxxx> > --- > As I wrote the perf-trace.c program, I was thinking what we really should have is the following API. We can keep this API, but what would be nice is: int tracefs_print_init(struct tracefs_instance *instance); int tracefs_print(struct tracefs_instance *instance, const char *fmt, ...); int tracefs_vprint(struct tracefs_instance *instance, const char *fmt, va_list ap); void tracefs_print_reset(struct tracefs_instance *instance); Where tracefs_print_init() will open the trace_marker for that instance (NULL being the top level), and storing it in the instance structure. tracefs_print() and tracefs_vprint() will check if the trace_marker file has already been opened (tracefs_print_init() was previously called), and if not, it will open it and keep it open. Then it will write to the trace_marker file the passed in print data after formatting it (see my trace_print in perf-trace.c). The tracefs_print_reset() will simply close the trace_marker file if it was previously opened, note, so will any of the destructors of the instance. We could also have: int tracefs_raw_print_init(struct tracefs_instance *instance); int tracefs_raw_print(struct tracefs_instance *instance, void *data, int len); void tracefs_raw_print_reset(struct tracefs_instance *instance); That is the same, but instead of writing string data to the trace_marker, it would write in memory into trace_marker_raw. -- Steve
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