Re: [PATCH] perf stat: Pass PERF_STAT_RUN environment variable for each run

Namhyung Kim
2014-07-18T05:06:11Z

Hi Arnaldo and Peter,

On Thu, 17 Jul 2014 10:09:43 -0300, Arnaldo Carvalho de Melo wrote:
> Em Thu, Jul 17, 2014 at 10:40:11AM +0200, Peter Zijlstra escreveu:
>> On Thu, Jul 17, 2014 at 05:31:14PM +0900, Namhyung Kim wrote:
>> > On Thu, Jul 17, 2014 at 5:26 PM, Peter Zijlstra <peterz@infradead.org> wrote:
>> > > On Thu, Jul 17, 2014 at 05:21:06PM +0900, Namhyung Kim wrote:
>> > >> When perf stat runs multiple times via -r option, it's sometimes
>> > >> useful for a workload to know which run it executing. So pass new
>> > >> PERF_STAT_RUN environment variable to the workload for each run
>> > >> (starting from 1).
>
>> > > This seems counter intuitive, runs should be _identical_ otherwise
>> > > there's no point. That means the workload should very much _not_ know
>> > > these things.
>
>> > But I think it can be useful if a workload wants to save logfiles
>> > based on the iteration number for example. If it doesn't want, it can
>> > just ignore. :)
>
>> That's the wrong way around. Also, there's --pre and --post hooks to
>> preserve logfiles if you really have to do that kind of thing.
>
> Agreed, one can script this using --pre or --post if needed.

Hmm... okay, I'll drop this then.

Thanks,
Namhyung