Em Fri, Oct 02, 2015 at 08:22:06PM +0000, Liang, Kan escreveu:
> > > > + if (interval < 10) {
> > > > + pr_err("print interval must be >= 10ms\n");
> > > > + parse_options_usage(stat_usage, options, "I",
> > > > 1);
> > > > + goto out;
> > > > + } else
> > > > + pr_warning("print interval < 100ms. "
> > > > + "The overhead percentage could be
> > > > high
> > in some cases. "
> > > > + "Please proceed with caution.\n");
> > >
> > > with '-I' 10 this warning flies away quite fast ;-)
> > >
> > > I guess it's better than nothing, and I'm not sure about putting some
> > > sleep after that warning..
> > >
> > > Acked-by: Jiri Olsa <jo...@kernel.org>
> >
> > Right, this should appear in the man page as well, I added the patch below,
> > we could also print that warning when the workload ends.
> OK. We can print the warning message again at the end as the patch below.
>
> +++ b/tools/perf/builtin-stat.c
> @@ -1377,6 +1377,11 @@ int cmd_stat(int argc, const char **argv, const char
> *prefix __maybe_unused)
> if (!forever && status != -1 && !interval)
> print_counters(NULL, argc, argv);
>
> + if (interval && interval < 100)
> + pr_warning("print interval < 100ms. "
> + "The overhead percentage could be high in some
> cases. "
> + "Please proceed with caution.\n");
Yeah, something like that, but the warning then becomes strange,
"proceed"? I guess that something like:
pr_warning("print interval < 100ms. "
"The overhead percentage could have been high. "
"Take that into account when interpreting the these
numbers.\n");
Right?
- Arnaldo
> +
> perf_evlist__free_stats(evsel_list);
> out:
> perf_evlist__delete(evsel_list);
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