From: Peter Zijlstra <peterz@infradead.org>
To: Andi Kleen <andi@firstfloor.org>
Cc: Robert Richter <robert.richter@amd.com>,
Ingo Molnar <mingo@kernel.org>,
Stephane Eranian <eranian@google.com>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] perf: Introduce function to report unsupported syscall attribute flags
Date: Wed, 12 Sep 2012 16:29:01 +0200 [thread overview]
Message-ID: <1347460141.15764.36.camel@twins> (raw)
In-Reply-To: <m2oblbz59d.fsf@firstfloor.org>
On Wed, 2012-09-12 at 07:26 -0700, Andi Kleen wrote:
> Peter Zijlstra <peterz@infradead.org> writes:
>
> > On Wed, 2012-09-12 at 13:01 +0200, Robert Richter wrote:
> >> + if (notsup)
> >> + pr_warn("perf: unsupported attribute flags: %016llx\n", notsup);
> >
> > This is a dmesg DoS..
> >
> > I'm also not sure dmesg is the right way.. could we not somehow change
> > the attrs to provide better diagnostic?
>
> Have a output argument for a string, that is then printed by the user tool?
>
> I agree it's a problem today, i usually have to resort to ftrace to
> figure out what'swrong.
Yeah, its a pain.. something I was thinking of is zero-ing out the
entire perf_event_attr and set the field that caused the fail to all 1s
(for however many bits that field is wide).
It would destroy the user input, but it also would provide better
feedback on what exact field you went astray.
prev parent reply other threads:[~2012-09-12 14:29 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-12 11:01 [PATCH] perf: Introduce function to report unsupported syscall attribute flags Robert Richter
2012-09-12 11:20 ` Peter Zijlstra
2012-09-12 13:02 ` Robert Richter
2012-09-12 14:26 ` Andi Kleen
2012-09-12 14:29 ` Peter Zijlstra [this message]
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