Messages in this thread | | | Subject | Re: [PATCH v2 0/6] perf tools: Use SIGUSR2 control data dumpping | From | "Wangnan (F)" <> | Date | Fri, 15 Apr 2016 21:41:04 +0800 |
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On 2016/4/15 21:35, Arnaldo Carvalho de Melo wrote: > Em Fri, Apr 15, 2016 at 04:14:26PM +0300, Adrian Hunter escreveu: >> On 15/04/16 03:19, Arnaldo Carvalho de Melo wrote: >>> Em Thu, Apr 14, 2016 at 02:21:59PM +0000, Wang Nan escreveu: >>>> This patch set is based on perf/core. >>>> >>>> v1 -> v2: Fix a bug which triggers output switching without >>>> '--switch-output' provided. >>>> >>>> Patch 5/10 in v1 has a bug: with following cmdline: >>>> # perf record -e intel_bts// --per-thread --snapshot -p 13588 >>> Ok, I moved the trigger stuff to a new file, util/trigger.h and added >>> missing man page entries, pushed to acme/perf/core, please take a look >>> if all is well before I push this to Ingo, tomorrow. >>> >>> Adrian/others, if you can, please take a look. >> Looks OK. I gave intel_pt a quick test with snapshot mode which didn't seem >> to be broken. >> >> Using --switch-output with intel_pt gives data that does not decode in the >> 2nd and subsequent files because there is no continuity of switch events. >> Also decoding the last file segfaults because the auxtrace index has not >> been split between the files. >> Probably need to prevent people using --switch-output with intel_pt, but >> I'll look at it more next week. > But the workflow of continuous tracing with regular analysis to go on > dumping uninteresting sections of the trace seems interesting? With the > massive volumes of data with Intel PT continuous tracing is deemded > impossible?
Another question: is it possible to make auxtrace (intel_bts, intel_bt and coresight) writing to overwritable ring buffer, so we can continuous trace them and silently drop uninteresting data?
Thank you.
> - Arnaldo > >>> - Arnaldo >>> >>>> Sending 'SIGUSR2' to perf triggers output switching, which us >>>> undesirable. The reason is in signal handler perf doesn't consider if >>>> user provided --switch-output explicitly. >>>> >>>> With this patchset applied: >>>> >>>> # /perf record --switch-output -e intel_bts// --per-thread --snapshot -p 13588 & >>>> [1] 15116 >>>> # kill -s SIGUSR2 15116 >>>> # [ perf record: dump data: Woken up 5 times ] >>>> [ perf record: Dump perf.data.2016041506170000 ] >>>> >>>> # kill -s SIGUSR2 15116 >>>> # [ perf record: dump data: Woken up 3 times ] >>>> [ perf record: Dump perf.data.2016041506170447 ] >>>> >>>> # fg >>>> /perf record --switch-output -e intel_bts// --per-thread --snapshot -p 13588 >>>> ^C[ perf record: Woken up 3 times to write data ] >>>> [ perf record: Dump perf.data.2016041506170785 ] >>>> [ perf record: Captured and wrote 0.012 MB perf.data.<timestamp> ] >>>> >>>> # ls -l ./perf.data* >>>> -rw------- 1 root root 4212888 Apr 15 06:17 ./perf.data.2016041506170000 >>>> -rw------- 1 root root 4212704 Apr 15 06:17 ./perf.data.2016041506170447 >>>> -rw------- 1 root root 18368 Apr 15 06:17 ./perf.data.2016041506170785 >>>> >>>> The first 2 perf.data works fine. The final one has no samples. >>>> >>>> And: >>>> # rm ./perf.data* >>>> # /perf record -e intel_bts// --per-thread --snapshot -p 13588 & >>>> [1] 15396 >>>> # kill -s SIGUSR2 15396 >>>> # kill -s SIGUSR2 15396 >>>> # fg >>>> /perf record -e intel_bts// --per-thread --snapshot -p 13588 >>>> ^C[ perf record: Woken up 9 times to write data ] >>>> [ perf record: Captured and wrote 8.012 MB perf.data ] >>>> >>>> # ls -l ./perf.data* >>>> -rw------- 1 root root 8417552 Apr 15 06:20 ./perf.data >>>> >>>> (In v1, the second test trigger output switching incorrectly) >>>> >>>> Patch 1-2/6 in this patchset makes switch output trigger similar to >>>> auxtrace snapshot trigger. Patch 1/6 introduces a 'trigger' class for >>>> them. It would be better to merge patch 1/6 with commit c0bdc1c ("perf >>>> record: Turns auxtrace_snapshot_enable into 3 states"). However, Ingo >>>> has collected that commit, so make it a separated patch. >>>> >>>> Signed-off-by: Wang Nan <wangnan0@huawei.com> >>>> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> >>>> Cc: Adrian Hunter <adrian.hunter@intel.com> >>>> Cc: Jiri Olsa <jolsa@kernel.org> >>>> Cc: Masami Hiramatsu <mhiramat@kernel.org> >>>> Cc: Namhyung Kim <namhyung@kernel.org> >>>> Cc: Zefan Li <lizefan@huawei.com> >>>> Cc: pi3orama@163.com >>>> Cc: He Kuang <hekuang@huawei.com> >>>> >>>> Wang Nan (6): >>>> perf tools: Extrace trigger class from auxtrace_snapshot >>>> perf record: Split output into multiple files via '--switch-output' >>>> perf record: Force enable --timestamp-filename when --switch-output is >>>> provided >>>> perf record: Disable buildid cache options by default in switch output >>>> mode >>>> perf record: Re-synthesize tracking events after output switching >>>> perf record: Generate tracking events for process forked by perf >>>> >>>> tools/perf/builtin-record.c | 147 +++++++++++++++++++++++++++++++------------- >>>> tools/perf/util/util.h | 60 ++++++++++++++++++ >>>> 2 files changed, 163 insertions(+), 44 deletions(-) >>>> >>>> -- >>>> 1.8.3.4
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