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Date: Mon, 16 Dec 2013 13:10:52 +0900 From: Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@...achi.com> To: Ian Webster <ian@...netaryresources.com> Cc: Steven Rostedt <rostedt@...dmis.org>, linux-kernel@...r.kernel.org Subject: Re: [PATCH v2] trace-cmd: Add record --clock option to specify a trace clock Hi Ian, (2013/12/13 8:30), Ian Webster wrote: > This change adds a --clock option to trace-cmd record. It simply writes > trace_clock on debugfs. Examples of valid choices on most systems are: local, > global, counter, and any other choice compatible with ftrace. Nice work! Please see my following comments. > This complements Yoshihiro Yunomae's change 8c9867c (trace-cmd: Add support for > extracting trace_clock in report). > > Signed-off-by: Ian Webster <ian@...netaryresources.com> > > --- > Changes per Steven's comments: > * add missing const > * preserve tab whitespace > > Documentation/trace-cmd-record.1.txt | 5 +++++ > trace-record.c | 19 +++++++++++++++++++ > trace-usage.c | 1 + > 3 files changed, 25 insertions(+) > > diff --git a/Documentation/trace-cmd-record.1.txt b/Documentation/trace-cmd-record.1.txt > index 832a257..5e83454 100644 > --- a/Documentation/trace-cmd-record.1.txt > +++ b/Documentation/trace-cmd-record.1.txt > @@ -240,6 +240,11 @@ OPTIONS > timestamp to gettimeofday which will allow wall time output from the > timestamps reading the created 'trace.dat' file. > > +*--clock* 'clock_name':: > + When an event is recorded into the ring buffer, a timestamp is added. This > + stamp comes from the specified clock. Ftrace uses the "local" clock by > + default. Other common clocks include: global, counter, uptime, perf, x86-tsc. > + > EXAMPLES > -------- > > diff --git a/trace-record.c b/trace-record.c > index 0199627..2143080 100644 > --- a/trace-record.c > +++ b/trace-record.c > @@ -399,6 +399,20 @@ static int set_ftrace(int set, int use_proc) > return 0; > } > > +static void set_trace_clock(const char *clock_choice) > +{ > + FILE *fp; > + char *path; > + > + path = tracecmd_get_tracing_file("trace_clock"); > + fp = fopen(path, "w"); > + if (!fp) > + die("writing to '%s'", path); > + tracecmd_put_tracing_file(path); > + fwrite(clock_choice, 1, strlen(clock_choice), fp); Please add an error check for fwrite(). If clock_choice is invalid, trace-cmd would better output the error report and die. > + fclose(fp); > +} > + > static char * > get_instance_file(struct buffer_instance *instance, const char *file) > { > @@ -2279,6 +2293,7 @@ static void record_all_events(void) > } > > enum { > + OPT_clock = 252, > OPT_nosplice = 253, > OPT_funcstack = 254, > OPT_date = 255, > @@ -2351,6 +2366,7 @@ void trace_record (int argc, char **argv) > {"func-stack", no_argument, NULL, OPT_funcstack}, > {"nosplice", no_argument, NULL, OPT_nosplice}, > {"help", no_argument, NULL, '?'}, > + {"clock", required_argument, NULL, OPT_clock}, > {NULL, 0, NULL, 0} > }; > > @@ -2530,6 +2546,9 @@ void trace_record (int argc, char **argv) > case OPT_nosplice: > recorder_flags |= TRACECMD_RECORD_NOSPLICE; > break; > + case OPT_clock: > + set_trace_clock(optarg); > + break; This implementation does not support multiple buffers. trace_clock had better be changed after sub-buffers are created, I think. Example: trace-cmd record -e sched --clock local -B foo -e block --clock x86-tsc Thanks, Yoshihiro YUNOMAE -- Yoshihiro YUNOMAE Software Platform Research Dept. Linux Technology Center Hitachi, Ltd., Yokohama Research Laboratory E-mail: yoshihiro.yunomae.ez@...achi.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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