Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030340AbVLVWAU (ORCPT ); Thu, 22 Dec 2005 17:00:20 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030337AbVLVWAU (ORCPT ); Thu, 22 Dec 2005 17:00:20 -0500 Received: from mf00.sitadelle.com ([212.94.174.67]:35180 "EHLO smtp.cegetel.net") by vger.kernel.org with ESMTP id S1030340AbVLVWAT (ORCPT ); Thu, 22 Dec 2005 17:00:19 -0500 Message-ID: <43AB21F1.8090600@cosmosbay.com> Date: Thu, 22 Dec 2005 23:00:17 +0100 From: Eric Dumazet User-Agent: Thunderbird 1.5 (Windows/20051201) MIME-Version: 1.0 To: george@mvista.com Cc: Ingo Molnar , Steven Rostedt , Pekka Enberg , Christoph Lameter , Alok N Kataria , Shobhit Dayal , Shai Fultheim , Matt Mackall , Andrew Morton , john stultz , Gunter Ohrner , linux-kernel@vger.kernel.org Subject: Re: [PATCH RT 00/02] SLOB optimizations References: <1135093460.13138.302.camel@localhost.localdomain> <20051220181921.GF3356@waste.org> <1135106124.13138.339.camel@localhost.localdomain> <84144f020512201215j5767aab2nc0a4115c4501e066@mail.gmail.com> <1135114971.13138.396.camel@localhost.localdomain> <20051221065619.GC766@elte.hu> <43A90225.4060007@cosmosbay.com> <20051221074346.GA2398@elte.hu> <43A90C07.4000003@cosmosbay.com> <20051222211132.GA21742@elte.hu> <43AB1E55.6040703@mvista.com> In-Reply-To: <43AB1E55.6040703@mvista.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1095 Lines: 33 George Anzinger a ?crit : > > >> that's just the profiling interrupt hitting them. You should not >> analyze irq-safe code with a non-NMI profiling interrupt. >> >> CLI/STI is extremely fast. (In fact in the -rt tree i'm using them >> within mutexes instead of preempt_enable()/preempt_disable(), because >> they are faster and generate less register side-effect.) >> > Hm... I rather thought that the cli would cause a rather large hit on > the pipeline and certainly on OOE. Is your observation based on any > particular instruction stream? Sti, on the otherhand should be fast... Just to be exact, the 'cli' is coded as 3 instruction : pushfq popq (%rsp) cli and the 'sti' is coded as 2 instructions : pushq (%rsp) popfq And 'popfq' seems to be expensive, at least on Opteron machines and if oprofile is not completely wrong... Eric - 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/