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Date: Thu, 3 Nov 2011 17:08:59 -0700 From: Arun Sharma <asharma@...com> To: Andrew Vagin <avagin@...nvz.org> CC: <linux-kernel@...r.kernel.org>, Peter Zijlstra <a.p.zijlstra@...llo.nl>, Paul Mackerras <paulus@...ba.org>, Ingo Molnar <mingo@...e.hu>, Arnaldo Carvalho de Melo <acme@...stprotocols.net>, <devel@...nvz.org> Subject: Re: [PATCH 3/4] perf: teach perf inject to merge sched_stat_* and sched_switch events On 11/2/11 3:59 PM, Andrew Vagin wrote: > + event_sw = (union perf_event *)&ent->header; This causes problems with -Wstrict-aliasing=3. I noticed that the suggested cmdline is: perf script record sched-stat -- -e sched:sched_stat_sleep I'd much prefer something along the lines of: perf script record sched-stat -e <events> -- sleep 1 Also, the perf inject command is a bit unforgiving when the user makes some mistakes (eg: didn't specify -e sched:sched_stat_sleep). The failure mode is hard to understand (perf report -i perf.data.d fails with "no samples"). Doing it directly: # perf record -ag -e sched:sched_switch --filter "prev_state == 1 || prev_state == 2" -e sched:sched_process_exit,sched:sched_stat_sleep,sched:sched_stat_iowait -- sleep 1 # perf inject -v -s -i perf.data -o perf.data.d results in a whole bunch of: Could not find sched_switch for pid 16188 Could not find sched_switch for pid 16212 Could not find sched_switch for pid 1500 Could not find sched_switch for pid 16195 Could not find sched_switch for pid 16179 I think this is the same issue you referenced in "Known issues". Although I'm able to get some profiling info out of perf.data.d, the process I really wanted to trace got zero samples. -Arun -- 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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