From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: with ECARTIS (v1.0.0; list xfs); Fri, 22 Feb 2008 16:06:22 -0800 (PST) Received: from larry.melbourne.sgi.com (larry.melbourne.sgi.com [134.14.52.130]) by oss.sgi.com (8.12.11.20060308/8.12.11/SuSE Linux 0.7) with SMTP id m1N06565030504 for ; Fri, 22 Feb 2008 16:06:16 -0800 Date: Sat, 23 Feb 2008 11:06:12 +1100 From: David Chinner Subject: Re: Marking inode dirty latency > 1000 msec on XFS! Message-ID: <20080223000612.GE155259@sgi.com> References: <47B5DD9C.3080906@gmail.com> <47BE6C5C.2000605@sgi.com> <47BE8EE8.5020005@gmail.com> <47BEA1E7.3010107@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <47BEA1E7.3010107@gmail.com> Sender: xfs-bounce@oss.sgi.com Errors-to: xfs-bounce@oss.sgi.com List-Id: xfs To: =?iso-8859-1?B?VPZy9ms=?= Edwin Cc: lachlan@sgi.com, Arjan van de Ven , xfs@oss.sgi.com, David Chinner On Fri, Feb 22, 2008 at 12:20:23PM +0200, Török Edwin wrote: > Török Edwin wrote: > >> What would be useful here is the > >> average latency time. The average might actually be quite low but if > >> just > >> once we have a maximum that is unusually large then just looking at that > >> figure can be misleading. > >> > > > > I'll try to collect the raw numbers from /proc/latency_stats, that > > contain a count, total time, and max time. > > I was not able to reproduce the 1 second latency with David Chinner's > reduce xaild wakeups patch, the maximum latency I got was 685 msec. ..... > > > ---------------- > 2 47699 36897 xfs_buf_free default_wake_function xfs_buf_lock xfs_getsb .... > > Average = 478072 usecs > ----------------- ..... > ----------- > 1 685021 685021 xfs_buf_free default_wake_function xfs_buf_lock > xfs_getsb xfs_trans_getsb xfs_trans_apply_sb_deltas _xfs_trans_commit ...... Note the xfs_getsb() call in there - that's what the lazy-count option avoids. That's waiting in the transaction subsystem to apply delta's to the superblock that is currently locked. Converting to a lazy-count filesystem is experimental right now; it may eat your data. If you still want to try, apply the patch in this email and convert it: http://oss.sgi.com/archives/xfs/2008-02/msg00295.html Cheers, Dave. -- Dave Chinner Principal Engineer SGI Australian Software Group