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Message-ID: <87vc0c4ny2.fsf@sejong.aot.lge.com> Date: Fri, 01 Nov 2013 15:48:37 +0900 From: Namhyung Kim <namhyung@...nel.org> To: Ingo Molnar <mingo@...nel.org> Cc: Arnaldo Carvalho de Melo <acme@...stprotocols.net>, Peter Zijlstra <a.p.zijlstra@...llo.nl>, Paul Mackerras <paulus@...ba.org>, Namhyung Kim <namhyung.kim@....com>, LKML <linux-kernel@...r.kernel.org>, Frederic Weisbecker <fweisbec@...il.com>, Stephane Eranian <eranian@...gle.com>, Jiri Olsa <jolsa@...hat.com>, Rodrigo Campos <rodrigo@...g.com.ar>, Arun Sharma <asharma@...com> Subject: Re: [RFC/PATCHSET 00/14] perf report: Add support to accumulate hist periods (v2) Hi Ingo, On Thu, 31 Oct 2013 09:09:32 +0100, Ingo Molnar wrote: > * Namhyung Kim <namhyung@...nel.org> wrote: > >> When the -g cumulative option is given, it'll be shown like this: >> >> $ perf report -g cumulative --stdio >> >> # Overhead Overhead (Acc) Command Shared Object Symbol >> # ........ .............. ....... ................. ....................... >> # >> 0.00% 88.29% abc libc-2.17.so [.] __libc_start_main >> 0.00% 88.29% abc abc [.] main >> 0.00% 88.29% abc abc [.] c >> 0.00% 88.29% abc abc [.] b >> 88.29% 88.29% abc abc [.] a >> 0.00% 11.61% abc ld-2.17.so [k] _dl_sysdep_start >> 0.00% 9.43% abc ld-2.17.so [.] dl_main >> 9.43% 9.43% abc ld-2.17.so [.] _dl_relocate_object >> 2.27% 2.27% abc [kernel.kallsyms] [k] page_fault >> 0.00% 2.18% abc ld-2.17.so [k] _dl_start_user >> 0.00% 0.10% abc ld-2.17.so [.] _start >> >> As you can see __libc_start_main -> main -> c -> b -> a callchain >> show up in the output. > > This looks really useful! Thanks! :) > > A couple of details: > > 1) > > This is pretty close to SysProf output, right? So why not use the > well-known SysProf naming and call the first column 'self' and the > second column 'total'? I think those names are pretty intuitive and > it would help people who come from SysProf over to perf. Okay, I can do it. (Although sysprof seems to call it 'cumulative' rather than 'total' - but I think the 'total' is better since it's simpler and shorter.) > > 2) > > Is it possible to configure the default 'report -g' style, so that > people who'd like to use it all the time don't have to type '-g > cumulative' all the time? Hmm.. maybe I can add support for the 'report.call-graph' config option. > > 3) > > I'd even argue that we enable this reporting feature by default, if > a data file includes call-chain data: the first column will still > show the well-known percentage that perf report produces today, the > second column will be a new feature in essence. > > The only open question would be, by which column should we sort: > 'sysprof style' sorts by 'total', 'perf style' sorts by 'self'. > Agreed? Right, I defaulted to go by 'total'. But we can add an option for it. > > 4) > > This is not directly related to the new feature you added: > call-graph profiling still takes quite a bit of time. It might make > sense to save the ordered histogram to a perf.data.ordered file, so > that repeat invocations of 'perf report' don't have to recalculate > everything again and again? > > This file would be maintained transparently and would only be > re-created when the perf.data file changes, or something like that. Hmm.. good idea. We may discuss it along with Jiri's multiple file storage patches. I haven't had a time to review - maybe next week. > > 5) > > I realize that this is an early RFC, still there are some usability > complaints I have about call-graph recording/reporting which should > be addressed before adding new features. > > For example I tried to get a list of the -g output modi via: > > $ perf report -g help > > Which produced a lot of options - I think it should produce only a > list of -g options. Right. I have a patchset for this. Will send it soon. > It also doesn't list cumulative: > > -g, --call-graph <output_type,min_percent[,print_limit],call_order> > Display callchains using output_type > (graph, flat, fractal, or none) , min percent threshold, optional > print limit, callchain order, key (function or address). Default: > fractal,0.5,callee,function Ah, I forgot to add it. Will fix! > > Also, the list is very long and not very readable - I think there > should be more newlines. > > Then I tried to do: > > $ perf report -g > > which, somewhat surprisingly, was accepted. Given that call-graph > perf.data is recognized automatically by 'perf report', the -g > option should only accept -g <type> syntax and provide a list of > options when '-g' or '-g help' is provided. Will check. > > 6) > > A similar UI problem exists on the 'perf record' side: 'perf record > --call-graph help' should produce a specific list of call-graph > possibilities, not the two screens full output it does today. Right. The patch will come soonish. :) > >> I know it have some rough edges or even bugs, but I really want to >> release it and get reviews. It does not handle event groups and >> annotations and it has a bug on TUI. >> >> You can also get this series on 'perf/cumulate-v2' branch in my tree at: >> >> git://git.kernel.org/pub/scm/linux/kernel/git/namhyung/linux-perf.git > > So I tried it out on top of tip:master, with your testcase, and in > the --stdio case it works very well: > > # Overhead Overhead (Acc) Command Shared Object Symbol > # ........ .............. ....... ................. .......................................... > # > 0.00% 100.00% abc abc [.] _start > 0.00% 100.00% abc libc-2.17.so [.] __libc_start_main > 0.00% 100.00% abc abc [.] main > 0.00% 100.00% abc abc [.] c > 0.00% 100.00% abc abc [.] b > 99.79% 100.00% abc abc [.] a > 0.01% 0.21% abc [kernel.kallsyms] [k] apic_timer_interrupt > > In the TUI output the 'c' entry is not visible: > > 99.79% 100.00% abc abc [.] a > 0.00% 99.79% abc abc [.] b > 0.01% 0.21% abc [kernel.kallsyms] [k] apic_timer_interrupt > 0.00% 0.19% abc [kernel.kallsyms] [k] smp_apic_timer_interrupt > > I suspect this is the 'TUI bug' you mentioned? Exactly, I'll dig into it. > >> Any comments are welcome, thanks. > > Cool stuff, let's fix & merge it ASAP! :-) hehe, 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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