Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750965AbVJSN4W (ORCPT ); Wed, 19 Oct 2005 09:56:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750970AbVJSN4W (ORCPT ); Wed, 19 Oct 2005 09:56:22 -0400 Received: from pentafluge.infradead.org ([213.146.154.40]:62654 "EHLO pentafluge.infradead.org") by vger.kernel.org with ESMTP id S1750957AbVJSN4V (ORCPT ); Wed, 19 Oct 2005 09:56:21 -0400 Subject: Re: [PATCH 1/1] indirect function calls elimination in IO scheduler From: Arjan van de Ven To: "Ananiev, Leonid I" Cc: linux-kernel@vger.kernel.org, rdunlap@xenotime.net In-Reply-To: <6694B22B6436BC43B429958787E4549892AE55@mssmsx402nb> References: <6694B22B6436BC43B429958787E4549892AE55@mssmsx402nb> Content-Type: text/plain Date: Wed, 19 Oct 2005 15:56:11 +0200 Message-Id: <1129730171.2822.36.camel@laptopd505.fenrus.org> Mime-Version: 1.0 X-Mailer: Evolution 2.2.3 (2.2.3-2.fc4) Content-Transfer-Encoding: 7bit X-Spam-Score: 2.9 (++) X-Spam-Report: SpamAssassin version 3.0.4 on pentafluge.infradead.org summary: Content analysis details: (2.9 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- 0.1 RCVD_IN_SORBS_DUL RBL: SORBS: sent directly from dynamic IP address [80.57.133.107 listed in dnsbl.sorbs.net] 2.8 RCVD_IN_DSBL RBL: Received via a relay in list.dsbl.org [] X-SRS-Rewrite: SMTP reverse-path rewritten from by pentafluge.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 891 Lines: 21 On Wed, 2005-10-19 at 17:08 +0400, Ananiev, Leonid I wrote: > >From Leonid Ananiev > > Fully modular io schedulers and enables online switching between > them was introduced in Linux 2.6.10 but as a result percentage of CPU > using by kernel was increased and performance degradation is marked on > Itanium. A cause of degradation is in more steps for indirect IO > scheduler type specific function calls. > The patch eliminates 45 indirect function calls in 16 elevator > functions. does it really reduce those function calls? I thought it only reduced a few pointers to be followed, but not the actual indirect function calls! - 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/