linux-kernel - Re: [PATCH v5 0/7] Event parsing fixes

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: <CAP-5=fW=eYuKQtnd=1gM3wh7MubZ+P56ZCHn9dwvkhUn_NQZMQ@mail.gmail.com>
Date: Wed, 28 Aug 2024 10:14:01 -0700
From: Ian Rogers <irogers@...gle.com>
To: Andi Kleen <ak@...ux.intel.com>
Cc: James Clark <james.clark@...aro.org>, linux-perf-users@...r.kernel.org, 
	kan.liang@...ux.intel.com, John Garry <john.g.garry@...cle.com>, 
	Will Deacon <will@...nel.org>, Mike Leach <mike.leach@...aro.org>, Leo Yan <leo.yan@...ux.dev>, 
	Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>, 
	Arnaldo Carvalho de Melo <acme@...nel.org>, Namhyung Kim <namhyung@...nel.org>, 
	Mark Rutland <mark.rutland@....com>, 
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Jiri Olsa <jolsa@...nel.org>, 
	Adrian Hunter <adrian.hunter@...el.com>, Weilin Wang <weilin.wang@...el.com>, 
	Athira Rajeev <atrajeev@...ux.vnet.ibm.com>, Dominique Martinet <asmadeus@...ewreck.org>, 
	Yang Jihong <yangjihong@...edance.com>, Colin Ian King <colin.i.king@...il.com>, 
	Ze Gao <zegao2021@...il.com>, Yunseong Kim <yskelg@...il.com>, 
	Sun Haiyong <sunhaiyong@...ngson.cn>, Jing Zhang <renyu.zj@...ux.alibaba.com>, 
	Yicong Yang <yangyicong@...ilicon.com>, linux-arm-kernel@...ts.infradead.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v5 0/7] Event parsing fixes

On Wed, Aug 28, 2024 at 10:02 AM Andi Kleen <ak@...ux.intel.com> wrote:
>
> On Wed, Aug 28, 2024 at 03:07:14PM +0100, James Clark wrote:
> > I rebased this one and made some other fixes so that I could test it,
> > so I thought I'd repost it here in case it's helpful. I also added a
> > new test.
> >
> > But for the testing it all looks ok.
> >
> > There is one small difference where it now hides _all_ <not supported>
> > events, when previously it would only hide some selected subset of
> > events like "stalled-cycles-frontend". I think this is now more
> > consistent across platforms because, for example, Apple M only has
> > cycles and instructions, and the rest of the default events would
> > always show as <not supported> there.
>
> I'm not a big fan of hiding all of <unsupported>, when they are explicitly
> specified on the command line they should be absolutely shown.
>
> I do have tools that specify events on the command line and expect
> the same order/events in the output. This might well cause breakage.

The patch series doesn't do this, it just doesn't display unsupported
events that came from the set of default events - default evsels have
a "skippable" flag set. In patch 3 James has added to
should_skip_zero_counter in stat-display.c:

+       /*
+        * Skip unsupported default events when not verbose. (default events
+        * are all marked 'skippable').
+        */
+       if (verbose == 0 && counter->skippable && !counter->supported)
+               return true;

Thanks,
Ian