From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nick Piggin Subject: Re: Where is the performance bottleneck? Date: Wed, 31 Aug 2005 22:24:25 +1000 Message-ID: <4315A179.8070102@yahoo.com.au> References: <20050829202529.GA32214@midnight.suse.cz> <20050831071126.GA7502@midnight.ucw.cz> <20050831072644.GF4018@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Holger Kiehl Cc: Jens Axboe , Vojtech Pavlik , linux-raid , linux-kernel List-Id: linux-raid.ids Holger Kiehl wrote: > 3236497 total 1.4547 > 2507913 default_idle 52248.1875 > 158752 shrink_zone 43.3275 > 121584 copy_user_generic_c 3199.5789 > 34271 __wake_up_bit 713.9792 > 31131 __make_request 23.1629 > 22096 scsi_request_fn 18.4133 > 21915 rotate_reclaimable_page 80.5699 ^^^^^^^^^ I don't think this function should be here. This indicates that lots of writeout is happening due to pages falling off the end of the LRU. There was a bug recently causing memory estimates to be wrong on Opterons that could cause this I think. Can you send in 2 dumps of /proc/vmstat taken 10 seconds apart while you're writing at full speed (with 2.6.13 or the latest -git tree). A dump of /proc/zoneinfo and /proc/meminfo while the write is going on would be helpful too. Thanks, Nick -- SUSE Labs, Novell Inc. Send instant messages to your online friends http://au.messenger.yahoo.com