Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S266808AbUJFDoA (ORCPT ); Tue, 5 Oct 2004 23:44:00 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266833AbUJFDoA (ORCPT ); Tue, 5 Oct 2004 23:44:00 -0400 Received: from smtp203.mail.sc5.yahoo.com ([216.136.129.93]:3765 "HELO smtp203.mail.sc5.yahoo.com") by vger.kernel.org with SMTP id S266808AbUJFDn6 (ORCPT ); Tue, 5 Oct 2004 23:43:58 -0400 Message-ID: <416369F9.7050205@yahoo.com.au> Date: Wed, 06 Oct 2004 13:43:53 +1000 From: Nick Piggin User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.2) Gecko/20040820 Debian/1.7.2-4 X-Accept-Language: en MIME-Version: 1.0 To: Jeff Garzik CC: Andrea Arcangeli , Robert Love , Roland Dreier , linux-kernel@vger.kernel.org Subject: Re: Preempt? (was Re: Cannot enable DMA on SATA drive (SCSI-libsata, VIA SATA)) References: <4136E4660006E2F7@mail-7.tiscali.it> <41634236.1020602@pobox.com> <52is9or78f.fsf_-_@topspin.com> <4163465F.6070309@pobox.com> <41634A34.20500@yahoo.com.au> <41634CF3.5040807@pobox.com> <1097027575.5062.100.camel@localhost> <20041006015515.GA28536@havoc.gtf.org> <41635248.5090903@yahoo.com.au> <20041006020734.GA29383@havoc.gtf.org> <20041006031726.GK26820@dualathlon.random> <4163660A.4010804@pobox.com> In-Reply-To: <4163660A.4010804@pobox.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 933 Lines: 26 Jeff Garzik wrote: > Andrea Arcangeli wrote: > >> So I disagree with your claim that preempt risks to hide inefficient >> code, there are many other (probably easier) ways to detect inefficient >> code than to check the latencies. > > > > You're ignoring the argument :) > > If users and developers are presented with the _impression_ that long > latency code paths don't exist, then nobody is motivated to profile them > (with any tool), much less fix them. > But even without preempt you'd still have to profile the latency. If anyone with !preempt notices unacceptable latency, then they can report and/or profile and fix it. If not, then !preempt latency must be acceptable. - 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/