From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265810AbUHAL3L (ORCPT ); Sun, 1 Aug 2004 07:29:11 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265823AbUHAL3K (ORCPT ); Sun, 1 Aug 2004 07:29:10 -0400 Received: from mx1.redhat.com ([66.187.233.31]:37082 "EHLO mx1.redhat.com") by vger.kernel.org with ESMTP id S265810AbUHAL3H (ORCPT ); Sun, 1 Aug 2004 07:29:07 -0400 Date: Sun, 1 Aug 2004 07:28:18 -0400 (EDT) From: Ingo Molnar X-X-Sender: mingo@devserv.devel.redhat.com To: Lee Revell cc: Ingo Molnar , linux-kernel , Andrew Morton , Scott Wood Subject: Re: [patch] voluntary-preempt-2.6.8-rc2-M5 In-Reply-To: <1091234100.1677.41.camel@mindpipe> Message-ID: References: <1090732537.738.2.camel@mindpipe> <1090795742.719.4.camel@mindpipe> <20040726082330.GA22764@elte.hu> <1090830574.6936.96.camel@mindpipe> <20040726083537.GA24948@elte.hu> <1090832436.6936.105.camel@mindpipe> <20040726124059.GA14005@elte.hu> <20040726204720.GA26561@elte.hu> <20040729222657.GA10449@elte.hu> <1091141622.30033.3.camel@mindpipe> <20040730064431.GA17777@elte.hu> <1091228074.805.6.camel@mindpipe> <1091234100.1677.41.camel@mindpipe> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 30 Jul 2004, Lee Revell wrote: > Results with 2.6.8-rc2-M5: > > Configuration max usecs > ----------------------------------------------------------------- > All IRQs threaded 370 > Soundcard IRQ not threaded 335 > Soundcard IRQ not threaded + max_sectors_kb -> 64 161 > > So, it looks like the added configurability does add some overhead - 161 > usecs vs. 50. [...] +110 usecs is too much to be explained by redirection and configurability overhead. The configurability overhead is near zero. could you try to repeat the '50 usecs' test with -L2 [that was the one you used?] to make sure it's repeatable? The latencies of -L2 and -M5 should be near identical. The configurability should at most cause a 1-2 usecs overhead - definitely not two orders of magnitude higher. So if there's a difference then i must have degraded one of the latency reduction changes between L2 and M5. Ingo