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Date: Thu, 13 Sep 2012 17:21:45 +0200
From: Robert Richter <robert.richter@amd.com>
To: Ingo Molnar <mingo@kernel.org>
CC: Arnaldo Carvalho de Melo <acme@redhat.com>, <linux-kernel@vger.kernel.org>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: Re: [PATCH] perf record: Change error message on failure
Message-ID: <20120913152145.GG8285@erda.amd.com>
References: <1347531654-16024-1-git-send-email-robert.richter@amd.com>
 <20120913150720.GA27411@gmail.com>
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On 13.09.12 17:07:20, Ingo Molnar wrote:
> 
> * Robert Richter <robert.richter@amd.com> wrote:
> 
> > Only report
> > 
> >  No CONFIG_PERF_EVENTS=y kernel support configured?
> > 
> > if the syscall fails with ENOSYS. In other cases CONFIG_PERF_EVENTS is
> > set and might confuse users. The default message is now:
> > 
> >  Not all events could be opened.
> 
> Indeed, and it would be nice to be even less passive-aggressive 
> and figure out and display the exact error condition?

The complete error message shows the error condition and is like the
following:

 # perf record -e cycles:ppk sleep 1
 
   Error: sys_perf_event_open() syscall returned with 22 (Invalid argument).  /bin/dmesg may provide additional information.
 
 Not all events could be opened.
 sleep: Terminated

-Robert

-- 
Advanced Micro Devices, Inc.
Operating System Research Center