Messages in this thread | | | Date | Wed, 27 May 2015 15:40:11 +0300 | From | Adrian Hunter <> | Subject | Re: [GIT PULL 00/37] perf/core improvements and fixes |
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On 27/05/15 15:35, Arnaldo Carvalho de Melo wrote: > Em Wed, May 27, 2015 at 09:38:47AM +0200, Ingo Molnar escreveu: >> * Arnaldo Carvalho de Melo <acme@kernel.org> wrote: >>> New features: > >>> - Intel PT support, should be complete now and possible to test it with what we >>> already have in the kernel, go, test it and report problems on lkml, I'm sure >>> Adrian will chime in if something doesn't work as documented. (Adrian Hunter) > >> So how can people follow your request? > > First by having access to a machine with these hardware features, which, > for one, I have no easy access to right now :-\ > >> The changelogs are minimal, sometimes they only say: > > They improved over time, over the many resubmits Adrian made, so some > progress was made on this front. > >> From 7a84d68975f34c912cb6ec8adb3c1869c15b5c36 Mon Sep 17 00:00:00 2001 >> From: Adrian Hunter <adrian.hunter@intel.com> >> Date: Fri, 22 May 2015 14:54:04 +0300 >> Subject: [PATCH] perf tools: Add Intel PT support > >> Add support for Intel Processor Trace. > >> there's almost zero comments added by these commits. > > I shouldn't have let some pass, granted. > >> This commit: >> >> 928541b6f51f perf tools: Take Intel PT into use >> >> adds 'some documentation' under ./Documentation/intel-pt.txt, but that text >> doesn't actually give any high level description, it doesn't give _any_ way for a >> user to discover Intel PT support on his own - unless he already knows it, which >> is kind of circular. > >> It doesn't describe which CPUs support Intel PT, what it is, how are people >> supposed to use it, what the high level capabilities and limitations are, etc. >> etc. > >> So this stuff is user and developer hostile at the moment. We can push this >> towards Linus only if this becomes _much_ more user and developer friendly. Near >> zero documentation and near zero comments in the code don't cut it really. > > Adrian, can you try to address this further, please?
Yes, I will mainly expand the information in tools/perf/Documentation/intel-pt.txt unless you have any other ideas.
> > Something like a handholding session, so that we don't have to dig thru > all the csets or patch series cover letters, telling: > > 1. What hardware one has to have to be able to test it > > 2. First command to use > > 3. What will be generated, how much space (a lot?) it will use on the > perf.data file, etc. > > 5. What commands have to be used on this perf.data file and what to > expect from it. > > I.e. a HOWTO that starts with a as short as possible description on how > to use it for the very first time, for people never exposed to Intel PT > but that can benefit from using it. > > Ingo, so I'll move these csets to a separate branch from where I can > work with Adrian and others to then try again to resubmit, but only on a > branch exclusively for this. > > Will resubmit a perf/core branch with the remaining bits soon. > > - Arnaldo > >
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