From: Peter Zijlstra <peterz@infradead.org>
To: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Ingo Molnar <mingo@elte.hu>, Jiri Olsa <jolsa@redhat.com>,
Lin Ming <ming.m.lin@intel.com>, rostedt <rostedt@goodmis.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
Stephane Eranian <eranian@google.com>
Subject: Re: [PATCH] perf, p4: Add format attributes
Date: Tue, 27 Mar 2012 17:05:59 +0200 [thread overview]
Message-ID: <1332860759.16159.233.camel@twins> (raw)
In-Reply-To: <20120327145728.GE11875@moon>
On Tue, 2012-03-27 at 18:57 +0400, Cyrill Gorcunov wrote:
> On Tue, Mar 27, 2012 at 04:50:42PM +0200, Peter Zijlstra wrote:
> > Subject: perf, p4: Add format attributes
> > From: Peter Zijlstra <a.p.zijlstra@chello.nl>
> > Date: Tue Mar 27 16:19:25 CEST 2012
> >
> > Steven reported his P4 not booting properly, the missing format
> > attributes cause a NULL ptr deref. Cure this by adding the missing
> > format specification.
> >
> > I took the format description out of the comment near
> > p4_config_pack*() and hope that comment is still relatively
> > accurate.
> >
> > Cc: Cyrill Gorcunov <gorcunov@openvz.org>
> > Cc: Lin Ming <ming.m.lin@intel.com>
> > Reported-by: Steven Rostedt <rostedt@goodmis.org>
> > Tested-by: Steven Rostedt <rostedt@goodmis.org>
> > Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
>
> Thanks a lot, Peter! This format description is somewhat
> new to me (I think I've missed when it was introduced first
> time).
Yeah, its all brand-spanking new stuff.. see
https://lkml.org/lkml/2012/1/16/146 , Jiri added a full fledged
bison/yacc parser to perf so we can now write events like:
perf stat -e cpu/event=0xb7,umask=0x01,offcore_rsp=0x500b/
and it uses /sys/bus/event_source/devices/cpu/format/* to figure out how
to convert that into perf_event_attr::config{,1,2} values.
So with this patch you could, on your P4, write:
perf stat -e cpu/cccr=0x1234,escr=0x4321,ht/
and it would construct the perf_event_attr::config value 0x92344321 for
you.
I've still not actually read the P4-PMU specs, so I don't know if
there's anything more convenient we can do on P4. If there's a
better/more useful format representation possible, don't hesitate to
send a patch! :-)
> Reviewed-by: Cyrill Gorcunov <gorcunov@openvz.org>
Thanks!
next prev parent reply other threads:[~2012-03-27 15:06 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-27 14:50 [PATCH] perf, p4: Add format attributes Peter Zijlstra
2012-03-27 14:57 ` Cyrill Gorcunov
2012-03-27 15:05 ` Cyrill Gorcunov
2012-03-27 15:05 ` Peter Zijlstra [this message]
2012-03-27 15:07 ` Peter Zijlstra
2012-03-27 15:12 ` Cyrill Gorcunov
2012-03-27 22:03 ` Cyrill Gorcunov
2012-03-27 22:05 ` Peter Zijlstra
2012-03-27 22:11 ` Cyrill Gorcunov
2012-04-03 8:11 ` [tip:perf/urgent] perf/x86/p4: " tip-bot for Peter Zijlstra
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