Messages in this thread | | | Date | Wed, 26 Oct 2011 09:18:28 -0200 | From | Arnaldo Carvalho de Melo <> | Subject | Re: [RFC PATCH 2/2] tools/perf: Make group_fd static and move its place in __perf_evsel__open() |
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Em Wed, Oct 26, 2011 at 02:26:03PM +0800, Deng-Cheng Zhu escreveu: > On 10/25/2011 11:23 PM, Arnaldo Carvalho de Melo wrote: > >Em Mon, Oct 24, 2011 at 12:03:28PM -0200, Arnaldo Carvalho de Melo escreveu: > >>Em Mon, Oct 24, 2011 at 06:57:00PM +0800, Deng-Cheng Zhu escreveu: > >>>__perf_evsel__open() is called per event, it does not work for all the > >>>grouped events at one time. So, currently group_fd will alway be -1 for
<SNIP>
> >>>+ static int group_fd = -1; > >>> if (!evsel->cgrp) > >>> pid = threads->map[thread];
> >>Lets not do it that way, using statics for this is humm, ugly, IMHO.
> >Can you try this patch?
> >I tested it with:
> >[root@emilia ~]# perf top -e cycles -e instructions --group
> Your patch does fix the group fd issue. But to get event grouping > workable, the event state fix is still needed. Please see the discussion
Can I have your "Reviewed-by:" or "Tested-by:" tag for this patch then?
> here: http://www.spinics.net/lists/mips/msg42190.html
> With _only_ your patch applied, I tested with the following commands on > MIPS 74K (4 counters available in total): > > perf stat -g -e > L1-dcache-load-misses,cycles,LLC-load-misses,iTLB-loads,instructions > find / >/dev/null > > I tried to group up to 5 events in the hope of seeing NOSPC error. But > the command didn't fail and output: > > Performance counter stats for 'find /': > > 9300823 L1-dcache-load-misses > <not counted> cycles > <not counted> LLC-load-misses > <not counted> iTLB-loads > <not counted> instructions > > 8.463207591 seconds time elapsed > > This is due to the event state check in validate_group() filtering out > the grouped events in OFF state. They are in OFF state because we are > running the command with the perf tool as opposed to attaching to an > existing task: > > builtin-stat.c:create_perf_stat_counter(): > > if (target_pid == -1 && target_tid == -1) { > attr->disabled = 1; > attr->enable_on_exec = 1; > }
But they should be in OFF state only till the target program gets exec'ed, right?
> I suppose X86 has this issue too -- collect_events() in validate_group() > won't do real work in the bottom half of the function.
I'm testing that now.
- Arnaldo
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