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Date: Tue, 29 Oct 2013 12:11:52 +0900 From: Namhyung Kim <namhyung@...nel.org> To: Arun Sharma <asharma@...com> Cc: Rodrigo Campos <rodrigo@...g.com.ar>, <namhyung.kim@....com>, <linux-kernel@...r.kernel.org>, <acme@...stprotocols.net>, <fweisbec@...il.com>, Stephane Eranian <eranian@...gle.com> Subject: Re: State of "perf: Add a new sort order: SORT_INCLUSIVE" Hi Arun, On Mon, 28 Oct 2013 09:43:21 -0700, Arun Sharma wrote: > On 10/28/13 2:29 AM, Rodrigo Campos wrote: >> On Mon, Oct 28, 2013 at 06:09:30PM +0900, Namhyung Kim wrote: >>> On Mon, 28 Oct 2013 08:42:44 +0000, Rodrigo Campos wrote: >>>> On Mon, Oct 28, 2013 at 02:09:49PM +0900, Namhyung Kim wrote: >>>>> Anyway, You can find the series and discussion on the link below: >>>>> >>>>> https://lkml.org/lkml/2012/9/13/81 >>>> >>>> I've read the cover letter for that series and probably because I don't know >>>> about perf internals I have a question: How will "--culumate" interact with >>>> "--sort=dso" for example ? >>>> >>>> I mean, is it possible for that to show more than 100% ? (if you add all the >>>> 93.35% in your example in the cover letter, or something similar). Or >>>> "--culumate --sort=dso" will just group together all entries that have a dso in >>>> the call chain ? >>> >>> Hmm.. I think --cumulate option is only meaningful when sort order >>> includes symbol. Maybe I can add support for --sort=dso case as well >>> but not sure it's worth. Do you think it's really needed? >> >> I don't know if it is *needed*, but that was what I need :) > > I suspect that users will find creative ways of using these options to > solve real world problems and we shouldn't restrict usage any more > than we need to to protect against obvious bugs/crashes. > > Also, what's the reasoning for --cumulate not being an option under > perf record -g ..,<order>? Sorry, I cannot understand you. The 'perf record' just saves sample data (and callchains) from the ring-buffer. All the processing happens in 'perf report'. I can't see what you expect from the 'perf record --cumulate'. Am I missing something? > > In order to integrate perf record -b and --cumulate, we'll have to > sort out the underlying infrastructure for processing callgraphs and > branch stacks. I think the main roadblock here is that one is > statistical and on many CPUs incomplete (only top N branches are > reported). > > Given that there are clear use cases in production involving complex > callgraphs, I'm for getting this support in first and then reconciling > the differences with perf record -b later. I think what Frederic said is that the code de-duplication of 'perf report' side. The branch stack and --cumulate are different - branch stack concentrates on the branch itself but --cumulate uses callchains to find parents and give some credit to them as side information. Thanks, Namhyung -- 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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