Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263801AbTKRWZL (ORCPT ); Tue, 18 Nov 2003 17:25:11 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263806AbTKRWZL (ORCPT ); Tue, 18 Nov 2003 17:25:11 -0500 Received: from mail005.syd.optusnet.com.au ([211.29.132.54]:50314 "EHLO mail005.syd.optusnet.com.au") by vger.kernel.org with ESMTP id S263801AbTKRWZF (ORCPT ); Tue, 18 Nov 2003 17:25:05 -0500 From: Peter Chubb MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <16314.39961.545212.446223@wombat.chubb.wattle.id.au> Date: Wed, 19 Nov 2003 09:24:25 +1100 To: kernwek jalsl Cc: root@chaos.analogic.com, linux-kernel@vger.kernel.org Subject: Re: softirqd In-Reply-To: <20031118063551.25057.qmail@web20710.mail.yahoo.com> References: <20031118063551.25057.qmail@web20710.mail.yahoo.com> X-Mailer: VM 7.14 under 21.4 (patch 14) "Reasonable Discussion" XEmacs Lucid Comments: Hyperbole mail buttons accepted, v04.18. X-Face: GgFg(Z>fx((4\32hvXq<)|jndSniCH~~$D)Ka:P@e@JR1P%Vr}EwUdfwf-4j\rUs#JR{'h# !]])6%Jh~b$VA|ALhnpPiHu[-x~@<"@Iv&|%R)Fq[[,(&Z'O)Q)xCqe1\M[F8#9l8~}#u$S$Rm`S9% \'T@`:&8>Sb*c5d'=eDYI&GF`+t[LfDH="MP5rwOO]w>ALi7'=QJHz&y&C&TE_3j! Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1343 Lines: 36 Kernwek Jalsl said: Kernwek> Sorry in case I was not very clear with my Kernwek> requirements. With real time interrupt I meant a Kernwek> real time task waiting for IO from this interrupt. Kernwek> Assume that I have a high priority interrupt and a Kernwek> real time task waiting for it. Well followimg are the Kernwek> various latencies involved: Kernwek> L1- interrupt latency Kernwek> L2- hard and soft IRQ completion Kernwek> L3 - scheduler latency Kernwek> L4 - scheduler completion Kernwek> L1 is pretty acceptable on Linux. I've been trying to measure this. On IA64 I'm measuring around 2.5microseconds (on a 900MHz machine). I personally think that this is too big, and could be reduced. One thing I think we need to do early in 2.7 is to merge all those architecture-dependent arch/XXX/kernel/irq.c files, and try to reduce the amount of duplicated work done in the new merged file and the lower level architecture-specific files. -- Dr Peter Chubb http://www.gelato.unsw.edu.au peterc AT gelato.unsw.edu.au The technical we do immediately, the political takes *forever* - 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/