linux-kernel - Re: perf: h/w counters not counted and no error/info reported to user

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Message-ID: <BANLkTi=uKSKNJCJquKm44ofMwcTmfwAPyw@mail.gmail.com>
Date:	Mon, 30 May 2011 17:04:33 -0400
From:	Ashwin Chaugule <ashbertslists@...il.com>
To:	David Ahern <dsahern@...il.com>
Cc:	Ingo Molnar <mingo@...e.hu>,
	Arnaldo Carvalho de Melo <acme@...stprotocols.net>,
	LKML <linux-kernel@...r.kernel.org>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>
Subject: Re: perf: h/w counters not counted and no error/info reported to user

Hi David,

On Fri, May 27, 2011 at 12:36 PM, David Ahern <dsahern@...il.com> wrote:
>
> Ok, I got it now. On some occasions for simple programs -- like sleep 1
> -- the counter reads show:
>
> cycles: 0 1066485 0
>
> While the counter value is non-0, the time enabled and running values
> are 0 and those latter two are used by stat to say "not-counted".

I've seen time-enabled = 0 too, but I suspected that's because on my
kernel the sched_clock implementation was missing. (defaults to a
jiffies based timer)
I saw your patch for initializing the fd's to -1's, but I'm unable to
see how that makes the value of time-enabled non zero ?

Cheers,
Ashwin
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