Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261391AbVDIVxg (ORCPT ); Sat, 9 Apr 2005 17:53:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261392AbVDIVxg (ORCPT ); Sat, 9 Apr 2005 17:53:36 -0400 Received: from pat.uio.no ([129.240.130.16]:49905 "EHLO pat.uio.no") by vger.kernel.org with ESMTP id S261391AbVDIVxe (ORCPT ); Sat, 9 Apr 2005 17:53:34 -0400 Subject: Re: bdflush/rpciod high CPU utilization, profile does not make sense From: Trond Myklebust To: Jakob Oestergaard Cc: Greg Banks , linux-kernel@vger.kernel.org In-Reply-To: <20050409213549.GW347@unthought.net> References: <20050406160123.GH347@unthought.net> <20050406231906.GA4473@sgi.com> <20050407153848.GN347@unthought.net> <1112890671.10366.44.camel@lade.trondhjem.org> <20050409213549.GW347@unthought.net> Content-Type: text/plain Date: Sat, 09 Apr 2005 17:52:32 -0400 Message-Id: <1113083552.11982.17.camel@lade.trondhjem.org> Mime-Version: 1.0 X-Mailer: Evolution 2.0.4 Content-Transfer-Encoding: 7bit X-UiO-Spam-info: not spam, SpamAssassin (score=-3.537, required 12, autolearn=disabled, AWL 1.41, FORGED_RCVD_HELO 0.05, UIO_MAIL_IS_INTERNAL -5.00) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1594 Lines: 40 lau den 09.04.2005 Klokka 23:35 (+0200) skreiv Jakob Oestergaard: > 2.6.11.6: (dual PIII 1GHz, 2G RAM, Intel e1000) > > File Block Num Seq Read Rand Read Seq Write Rand Write > Dir Size Size Thr Rate (CPU%) Rate (CPU%) Rate (CPU%) Rate (CPU%) > ------- ------ ------- --- ----------- ----------- ----------- ----------- > . 2000 4096 1 38.34 18.8% 19.61 6.77% 22.53 23.4% 6.947 15.6% > . 2000 4096 2 52.82 29.0% 24.42 9.37% 24.20 27.0% 7.755 16.7% > . 2000 4096 4 62.48 34.8% 33.65 17.0% 24.73 27.6% 8.027 15.4% > > > 44MiB/sec for 2.4 versus 22MiB/sec for 2.6 - any suggestions as to how > this could be improved? What happened to the retransmission rates when you changed to TCP? Note that on TCP (besides bumping the value for timeo) I would also recommend using a full 32k r/wsize instead of 4k (if the network is of decent quality, I'd recommend 32k for UDP too). The other tweak you can apply for TCP is to bump the value for /proc/sys/sunrpc/tcp_slot_table_entries. That will allow you to have several more RPC requests in flight (although that will also tie up more threads on the server). Don't forget that you need to unmount then mount again after making these changes (-oremount won't suffice). Cheers, Trond -- Trond Myklebust - 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/