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Message-ID: <53CCD3A7.5070002@intel.com> Date: Mon, 21 Jul 2014 11:47:35 +0300 From: Adrian Hunter <adrian.hunter@...el.com> To: Jiri Olsa <jolsa@...hat.com> CC: Jiri Olsa <jolsa@...nel.org>, linux-kernel@...r.kernel.org, Arnaldo Carvalho de Melo <acme@...nel.org>, Corey Ashford <cjashfor@...ux.vnet.ibm.com>, David Ahern <dsahern@...il.com>, Frederic Weisbecker <fweisbec@...il.com>, Ingo Molnar <mingo@...nel.org>, Jean Pihet <jean.pihet@...aro.org>, Namhyung Kim <namhyung@...nel.org>, Paul Mackerras <paulus@...ba.org>, Peter Zijlstra <a.p.zijlstra@...llo.nl> Subject: Re: [PATCHv3 00/19] perf tools: Factor ordered samples queue On 07/21/2014 11:02 AM, Jiri Olsa wrote: > On Mon, Jul 21, 2014 at 09:43:58AM +0300, Adrian Hunter wrote: >> On 07/21/2014 12:55 AM, Jiri Olsa wrote: >>> hi, >>> this patchset factors session's ordered samples queue, >>> and allows to limit the size of this queue. >>> >>> v3 changes: >>> - rebased to latest tip/perf/core >>> - add comment for WARN in patch 8 (David) >>> - added ordered-events debug variable (David) >>> - renamed ordered_events_(get|put) to ordered_events_(new|delete) >>> - renamed struct ordered_events_queue to struct ordered_events >>> >>> v2 changes: >>> - several small changes for review comments (Namhyung) >>> >>> >>> The report command queues events till any of following >>> conditions is reached: >>> - PERF_RECORD_FINISHED_ROUND event is processed >>> - end of the file is reached >>> >>> Any of above conditions will force the queue to flush some >>> events while keeping all allocated memory for next events. >>> >>> If PERF_RECORD_FINISHED_ROUND is missing the queue will >> >> Why is it missing? > > it's stored only for tracepoints now patch 17 fixies that Wouldn't that make a huge difference all by itself? I would make that the first patch, and measure the difference that it makes by itself. > >> >>> allocate memory for every single event in the perf.data. >>> This could lead to enormous memory consuption and speed >>> degradation of report command for huge perf.data files. >>> >>> With the quue allocation limit of 100 MB, I've got around >>> 15% speedup on reporting of ~10GB perf.data file. >> >> How do you know the results are still valid? Wouldn't it >> be better to wait that extra 15% and know that the data has >> been processed correctly? > > The HALF flush could cause the out of order message > (which I get occasionaly anyway). Patch 19 allows Occasional out-of-order messages would be worth investigating IMHO. Either there is a bug or there is some "interesting" data being recorded. > out of order events after HALF flush. > > The main reason for me was to control the memory allocation, > which could get enormous without ROUND events being stored. But now you are storing them... > The 100MB queue limit seems to be enough not to hit out of > order event due to the HALF flush. ...so is the 100MB limit needed at all if you have ROUND events? -- 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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