Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750763AbWCVExt (ORCPT ); Tue, 21 Mar 2006 23:53:49 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750765AbWCVExt (ORCPT ); Tue, 21 Mar 2006 23:53:49 -0500 Received: from smtp106.mail.mud.yahoo.com ([209.191.85.216]:32933 "HELO smtp106.mail.mud.yahoo.com") by vger.kernel.org with SMTP id S1750763AbWCVExs (ORCPT ); Tue, 21 Mar 2006 23:53:48 -0500 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com.au; h=Received:Message-ID:Date:From:User-Agent:X-Accept-Language:MIME-Version:To:CC:Subject:References:In-Reply-To:Content-Type:Content-Transfer-Encoding; b=Ody2BFxNeb0CMv1ZQMUTThNd2JeaJUXttvZZ9vrZ9VS/+91nukiLeLYvqS7sKvNSe85H+syuGY7zVIacdulBlGPMs+e2533cF1+xKLoSa/bPcvsqIqZwp6Ddwpsm9BrjOBVv2IOwUUCe3GokfCLx9gFYNH+gcmwYcZGjn00t1wU= ; Message-ID: <4420D82B.6080504@yahoo.com.au> Date: Wed, 22 Mar 2006 15:52:59 +1100 From: Nick Piggin User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.8) Gecko/20050927 Debian/1.7.8-1sarge3 X-Accept-Language: en MIME-Version: 1.0 To: Shaohua Li CC: lkml , Andrew Morton Subject: Re: [PATCH] less tlb flush in unmap_vmas References: <1142995088.11430.34.camel@sli10-desk.sh.intel.com> In-Reply-To: <1142995088.11430.34.camel@sli10-desk.sh.intel.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: 1058 Lines: 28 Shaohua Li wrote: >In unmaping region, if current task doesn't need reschedule, don't do a >tlb_finish_mmu. This can reduce some tlb flushes. > >In the lmbench tests, this patch gives 2.1% improvement on exec proc >item and 4.2% on sh proc item. > > The problem with this is that by the time we _do_ determine that a reschedule is needed, we might have built up a huge amount of work to do (which can probably be as much if not more exensive per-page as the unmapping), so scheduling latency can still be unacceptable so I'm afraid I don't think we can include this patch. One option I've been looking into is my "mmu gather in-place" that never needs extra tlb flushes and is always preemptible... so that may be a way forward. --- Send instant messages to your online friends http://au.messenger.yahoo.com - 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/