linux-kernel - Re: [PATCH v6 0/7] perf diff: diff cycles at basic block level

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20190702155138.GD15462@kernel.org>
Date:   Tue, 2 Jul 2019 12:51:38 -0300
From:   Arnaldo Carvalho de Melo <arnaldo.melo@...il.com>
To:     Jiri Olsa <jolsa@...hat.com>
Cc:     Jin Yao <yao.jin@...ux.intel.com>, jolsa@...nel.org,
        peterz@...radead.org, mingo@...hat.com,
        alexander.shishkin@...ux.intel.com, Linux-kernel@...r.kernel.org,
        ak@...ux.intel.com, kan.liang@...el.com, yao.jin@...el.com
Subject: Re: [PATCH v6 0/7] perf diff: diff cycles at basic block level

Em Fri, Jun 28, 2019 at 10:02:55AM +0200, Jiri Olsa escreveu:
> On Fri, Jun 28, 2019 at 05:22:57PM +0800, Jin Yao wrote:
> > In some cases small changes in hot loops can show big differences.
> > But it's difficult to identify these differences.
> > 
> > perf diff currently can only diff symbols (functions). We can also expand
> > it to diff cycles of individual programs blocks as reported by timed LBR.
> > This would allow to identify changes in specific code accurately.
> > 
> > With this patch set, for example,
> > 
> >  $ perf record -b ./div
> >  $ perf record -b ./div
> >  $ perf diff -c cycles
> > 
> >  # Event 'cycles'
> >  #
> >  # Baseline                                       [Program Block Range] Cycles Diff  Shared Object     Symbol
> >  # ........  ......................................................................  ................  ..................................
> >  #
> >      48.75%                                             [div.c:42 -> div.c:45]  147  div               [.] main
> >      48.75%                                             [div.c:31 -> div.c:40]    4  div               [.] main
> >      48.75%                                             [div.c:40 -> div.c:40]    0  div               [.] main
> >      48.75%                                             [div.c:42 -> div.c:42]    0  div               [.] main
> >      48.75%                                             [div.c:42 -> div.c:44]    0  div               [.] main
> >      19.02%                                 [random_r.c:357 -> random_r.c:360]    0  libc-2.23.so      [.] __random_r
 
> Reviewed-by: Jiri Olsa <jolsa@...nel.org>

Looks really nice, thanks, applied.

- Arnaldo