Date: Thu, 11 Jun 2015 11:03:35 -0300
From: Arnaldo Carvalho de Melo <acme@kernel.org>
To: kan.liang@intel.com
Cc: linux-kernel@vger.kernel.org, andi@firstfloor.org
Subject: Re: [PATCH 1/1] perf,tools: error out unsupported group leader
 immediately for perf stat
Message-ID: <20150611140335.GB2696@kernel.org>
References: <1434004360-8570-1-git-send-email-kan.liang@intel.com>
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Em Thu, Jun 11, 2015 at 02:32:40AM -0400, kan.liang@intel.com escreveu:
> perf stat ignores the unsupported event and continue to count supported
> event. But if the unsupported event is group leader, perf tool will
> crash. After applying this patch, the unsupported group leader will
> error out immediately.
 
> Without this patch:
> $ perf stat -x, -e '{node-prefetch-refs,cycles}' --  sleep 1
> perf: util/evsel.c:1009: get_group_fd: Assertion `!(fd == -1)' failed.
> Aborted (core dumped)
 
> With this patch:
> $ perf stat -x, -e '{node-prefetch-refs,cycles}' --  sleep 1
> Error:
> The node-prefetch-refs event is not supported.

I get something different, maybe I am missing a patch?

With this patch:

  [acme@zoo linux]$ perf stat -x, -e '{node-prefetch-refs,cycles}' -- sleep 1
  Error:
  The sys_perf_event_open() syscall returned with 22 (Invalid argument)
  for event (node-prefetch-refs).
  /bin/dmesg may provide additional information.
  No CONFIG_PERF_EVENTS=y kernel support configured?
  [acme@zoo linux]$ 

Applying it anyway, as it avoids a core dump and the message, albeit not
optimal, points to a problem with that event.

Have you tried this with other tools, like perf record?

- Arnaldo
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