From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Ahern Subject: Re: Using a new perf tool against an older kernel Date: Thu, 23 Jun 2011 08:22:36 -0600 Message-ID: <4E034C2C.30509@gmail.com> References: <4E026123.4060208@fb.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from mail-pw0-f46.google.com ([209.85.160.46]:53890 "EHLO mail-pw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758934Ab1FWOWo (ORCPT ); Thu, 23 Jun 2011 10:22:44 -0400 In-Reply-To: <4E026123.4060208@fb.com> Sender: linux-perf-users-owner@vger.kernel.org List-ID: To: Arun Sharma Cc: linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org On 06/22/2011 03:39 PM, Arun Sharma wrote: > > I ran into a few strange issues today using a new perf tool (3.0-rcX) > against a 2.6.38 based kernel. Basic things seem to work: > > # perf record -aR -- sleep 1 > [ perf record: Woken up 1 times to write data ] > [ perf record: Captured and wrote 0.443 MB perf.data (~19334 samples) ] > > But: > > # perf record -agR -- sleep 1 > [ perf record: Woken up 1 times to write data ] > [ perf record: Captured and wrote 1.558 MB perf.data (~68077 samples) ] > Can't find id 9's machine > Found 1 unknown events! > > Is this an older tool processing a perf.data file generated by a more > recent tool? > > If that is not the case, consider reporting to > linux-kernel@vger.kernel.org. > > I couldn't tell if this is kernel/user space incompatibility or tighter > error checking in the new perf tool. Before I start digging further, > thought I'd ask if this combination is supported. The error message > above doesn't ask me: > > Are you using an old kernel? 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). David > > -Arun > > -- > To unsubscribe from this list: send the line "unsubscribe > linux-perf-users" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html