DomainKey-Signature: a=rsa-sha1; c=nofws;
        d=gmail.com; s=gamma;
        h=date:from:to:cc:subject:message-id:references:mime-version
         :content-type:content-disposition:in-reply-to:user-agent;
        b=vLkudeVsiQAAPM66mb8ntN8G8YKCafcFLocU/Pd+6bKHsGaaTlZ+HBCPAWC07l/Fin
         bAbuoR8prPDZ/0OjLybngNz2N+9SO6WN4UkaUBJTdZ5Z1DNBW2uFrdqF7cpNe6ZJS7nz
         4E5PLsLOe1sRk/2it0z14+CqKvVQeOOBwwg54=
Date: Fri, 24 Jun 2011 02:11:03 +0200
From: Frederic Weisbecker <fweisbec@gmail.com>
To: Arun Sharma <asharma@fb.com>
Cc: David Ahern <dsahern@gmail.com>, linux-perf-users@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: Using a new perf tool against an older kernel
Message-ID: <20110624001100.GD8058@somewhere.redhat.com>
References: <4E026123.4060208@fb.com>
 <4E034C2C.30509@gmail.com>
 <4E03968A.5010008@fb.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <4E03968A.5010008@fb.com>
User-Agent: Mutt/1.5.21 (2010-09-15)
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1244
Lines: 36

On Thu, Jun 23, 2011 at 12:39:54PM -0700, Arun Sharma wrote:
> On 6/23/11 7:22 AM, David Ahern wrote:
> 
> >I have not seen issues like this using newer perf userspace against
> >older kernels. For example, my laptop was running Fedora 14 (2.6.35) and
> >now Fedora 15 (2.6.38.8) and I typically use latest perf builds (e.g.,
> >testing patches).
> 
> I narrowed it down to PERF_SAMPLE_RAW:
> 
> perf record -ag -- sleep 1
> 
> is fine, but:
> 
> perf record -agR -- sleep 1
> 
> fails for me most of the time. The reason I needed to use the -R in
> the first place is that "perf script" fails on older kernels with:
> 
> Samples do not contain timestamps.
> 
> With the newer perf, I don't get errors, but the timestamp field is
> invalid. So I need to use the -R flag to get valid timestamps +
> stacktraces out of "perf script".

I'm confused, you first said it happens with new tools on older kernel.

Can you tell us which combination of kernel/user raises the error? and
which error.

Thanks!
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/