From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Fri, 26 Jul 2002 02:27:01 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Fri, 26 Jul 2002 02:27:01 -0400 Received: from samba.sourceforge.net ([198.186.203.85]:38330 "HELO lists.samba.org") by vger.kernel.org with SMTP id ; Fri, 26 Jul 2002 02:27:00 -0400 From: Rusty Russell To: Ravikiran G Thirumalai Cc: linux-kernel@vger.kernel.org, torvalds@transmeta.com Subject: Re: Patch 2.5.25: Ensure xtime_lock and timerlist_lock are on difft cachelines In-reply-to: Your message of "Thu, 25 Jul 2002 20:45:12 +0530." <20020725204512.E3594@in.ibm.com> Date: Fri, 26 Jul 2002 16:24:51 +1000 Message-Id: <20020726063124.5114E45D6@lists.samba.org> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org In message <20020725204512.E3594@in.ibm.com> you write: > I've noticed that xtime_lock and timerlist_lock ends up on the same > cacheline all the time (atleaset on x86). Not a good thing for > loads with high xxx_timer and do_gettimeofday counts I guess (networking etc) .. Better might be to use the x86-64 trick of using sequence counters around do_gettimeofday, and avoid the xtime lock altogether. That will improve gettimeofday performance as well. Or you could try changing xtime lock to a brlock. FYI: as policy, I don't take optimization patches without measurements. I'm just not that smart. Thanks, Rusty. -- Anyone who quotes me in their sig is an idiot. -- Rusty Russell.