From mboxrd@z Thu Jan 1 00:00:00 1970 From: Miao Xie Subject: Re: problem with ceph and btrfs patch: set journal_info in async trans commit worker Date: Thu, 15 Nov 2012 13:18:14 +0800 Message-ID: <50A47B16.6040308@cn.fujitsu.com> References: <50A39FAF.50602@profihost.ag> Reply-To: miaox@cn.fujitsu.com Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Return-path: Received: from cn.fujitsu.com ([222.73.24.84]:37821 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1750784Ab2KOFSC (ORCPT ); Thu, 15 Nov 2012 00:18:02 -0500 In-Reply-To: <50A39FAF.50602@profihost.ag> Sender: ceph-devel-owner@vger.kernel.org List-ID: To: Stefan Priebe - Profihost AG Cc: Sage Weil , "ceph-devel@vger.kernel.org" , "linux-btrfs@vger.kernel.org" , Josef Bacik Hi, Stefan On wed, 14 Nov 2012 14:42:07 +0100, Stefan Priebe - Profihost AG wrote: > Hello list, > > i wanted to try out ceph with latest vanilla kernel 3.7-rc5. I was seeing a massive performance degration. I see around 22x btrfs-endio-write processes every 10-20 seconds and they run a long time while consuming a massive amount of CPU. > > So my performance of 23.000 iops drops to an up and down of 23.000 iops to 0 - avg is now 2500 iops instead of 23.000. > > Git bisect shows me commit: e209db7ace281ca347b1ac699bf1fb222eac03fe "Btrfs: set journal_info in async trans commit worker" as the problematic patch. > > When i revert this one everything is fine again. > > Is this known? Could you try the following patch? http://marc.info/?l=linux-btrfs&m=135175512030453&w=2 I think the patch Btrfs: set journal_info in async trans commit worker is not the real reason that caused the regression. I guess it is caused by the bug of the reservation. When we join the same transaction handle more than 2 times, the pointer of the reservation in the transaction handle would be lost, and the statistical data in the reservation would be corrupted. And then we would trigger the space flush, which may block your tasks. Thanks Miao > > Greets, > Stefan > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >