From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755169Ab1BIRrR (ORCPT ); Wed, 9 Feb 2011 12:47:17 -0500 Received: from mail-px0-f174.google.com ([209.85.212.174]:59873 "EHLO mail-px0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754742Ab1BIRrP (ORCPT ); Wed, 9 Feb 2011 12:47:15 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:user-agent:mime-version:to:cc:subject :references:in-reply-to:content-type:content-transfer-encoding; b=Z2yOCepvcCiLGWwTo6rCxHC5+K7OsdFeha8q1mFoflU9yJi7pq4pmhaVedF6KcDz+4 bKOTbTAhDyzTmWOKOdk0eEkb2ZRVocXtEd7K/ueBIvvpx5+ZqD6pQmDVxkKOGXrOArWP IJJY1vcSPzHMM1Y2+2UJ11hyE6equ24xJrHKY= Message-ID: <4D52D31E.5010801@gmail.com> Date: Wed, 09 Feb 2011 10:47:10 -0700 From: David Ahern User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.13) Gecko/20101209 Fedora/3.1.7-0.35.b3pre.fc13 Thunderbird/3.1.7 MIME-Version: 1.0 To: Jeff Moyer CC: linux-kernel@vger.kernel.org, Peter Zijlstra , Ingo Molnar , Paul Mackerras , Arnaldo Carvalho de Melo Subject: Re: perf on 2.6.38-rc4 wedges my box References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/09/11 10:38, Jeff Moyer wrote: > Hi, > > I'm trying out willy's ata_ram driver[1], and in so doing have managed to > wedge my box while using perf record on an aio-stress run: > > [root@metallica ~]# modprobe ata_ram capacity=2097152 preallocate=1 > [root@metallica ~]# ./aio-stress -O -o 0 -r 4 -d 32 -b 16 /dev/sds > adding stage write > starting with write > file size 1024MB, record size 4KB, depth 32, ios per iteration 8 > max io_submit 16, buffer alignment set to 4KB > threads 1 files 1 contexts 1 context offset 2MB verification off > adding file /dev/sds thread 0 > write on /dev/sds (621.30 MB/s) 1024.00 MB in 1.65s > thread 0 write totals (621.27 MB/s) 1024.00 MB in 1.65s > [root@metallica ~]# perf record -- ./aio-stress -O -o 0 -r 4 -d 32 -b 16 > /dev/sds Have you tried '-e cpu-clock' for S/W based profiling vs the default H/W profiling? Add -v to see if the fallback to S/W is happening now. David > adding stage write > starting with write > file size 1024MB, record size 4KB, depth 32, ios per iteration 8 > max io_submit 16, buffer alignment set to 4KB > threads 1 files 1 contexts 1 context offset 2MB verification off > adding file /dev/sds thread 0 > > and there it sits. On the console, I see: > > NOHZ: local_softirq_pending 100 > NOHZ: local_softirq_pending 100 > NOHZ: local_softirq_pending 100 > NOHZ: local_softirq_pending 100 > NOHZ: local_softirq_pending 100 > > The number of messages varies, but this is the most I've seen (it > doesn't keep repeating). At this point, the machine does not respond to > pings. As I don't have physical access at the moment, I can't try > alt-sysrq, but might be able to do that tomorrow. It's probably worth > noting that I've witnessed similar behavior with real devices, so it's > not just the ata_ram driver. > > Any ideas on how to track this down? > > Thanks! > > Jeff > > [1] http://git.kernel.org/?p=linux/kernel/git/willy/misc.git;a=shortlog;h=refs/heads/ata-ram > -- > 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/