Messages in this thread |  | | From | Namhyung Kim <> | Subject | Re: [RFC/PATCHSET 00/14] perf report: Add support to accumulate hist periods (v2) | Date | Fri, 01 Nov 2013 18:22:29 +0900 |
| |
On Fri, 1 Nov 2013 08:55:02 +0100, Ingo Molnar wrote: > * Namhyung Kim <namhyung@kernel.org> wrote: > >> > 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.) > > So sysprof-1.2 has the following two windows: > > 'functions', with 'self' and 'total' fields > 'descendants', with 'self' and 'cumulative' fields > > 'descendants' appears to be similar to the perf 'dso' concept.
Arh, okay. Thanks for the info.
> >> > 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. > > If we display your new 'total' field by default then it's not as > pressing to me :)
Do you mean -g cumulative without 'self' column?
> >> > 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. > > The purpose would be to allow people to do old-style 'sort by > function overhead' output, while still seeing the 'total' field as > well.
Right.
> > Btw., if anyone is interested in improving the GTK front-end, it > would be _really_ nice if it had a 'start profiling' button like > sysprof has today, with a 'samples' field showing the current number > of samples. (We could even improve upon sysprof by adding 'stop' > functionality as well ;-)
Wow, I'm impressed that the sysprof doesn't have one. :)
> > A bit like perf top, except the reporting session is hidden until > the user actively requests the profile. > > Maybe it could even be called a gtk version of 'perf top', with a > button to start/stop collection, with another button to > activate/deactivate reporting output, and yet another button to > reset the profiling buffer. > > With that feature set perf would be a ready sysprof workflow > replacement I think. (I've Cc:-ed Pekka, just in case! :-)
Sounds nice. I'm not sure I can have to a time to do it anytime soon.
> >> > 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. > > So Arnaldo tells me that with your and Frederic's latest > callgraph-speedup patches the parsing of perf.data got _really_ > fast, so maybe my performance complaint is moot and we should delay > complicating the primary perf.data file model with a 'cache' until > your patches are in and we see the full impact.
Okay, let's see what happens. :)
Thanks, Namhyung
|  |