Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261718AbVBWXcs (ORCPT ); Wed, 23 Feb 2005 18:32:48 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261676AbVBWXaX (ORCPT ); Wed, 23 Feb 2005 18:30:23 -0500 Received: from smtp201.mail.sc5.yahoo.com ([216.136.129.91]:905 "HELO smtp201.mail.sc5.yahoo.com") by vger.kernel.org with SMTP id S261710AbVBWX1x (ORCPT ); Wed, 23 Feb 2005 18:27:53 -0500 Message-ID: <421D1171.7070506@yahoo.com.au> Date: Thu, 24 Feb 2005 10:27:45 +1100 From: Nick Piggin User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.5) Gecko/20050105 Debian/1.7.5-1 X-Accept-Language: en MIME-Version: 1.0 To: Hugh Dickins CC: Lee Revell , Ingo Molnar , Andrew Morton , linux-kernel Subject: Re: More latency regressions with 2.6.11-rc4-RT-V0.7.39-02 References: <1109182061.16201.6.camel@krustophenia.net> <1109187381.3174.5.camel@krustophenia.net> <1109190614.3126.1.camel@krustophenia.net> In-Reply-To: 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: 1175 Lines: 31 Hugh Dickins wrote: > On Wed, 23 Feb 2005, Lee Revell wrote: > >>>>Thanks, your patch fixes the copy_pte_range latency. >> >>clear_page_range is also problematic. > > > Yes, I saw that from your other traces too. I know there are plans > to improve clear_page_range during 2.6.12, but I didn't realize that > it had become very much worse than its antecedent clear_page_tables, > and I don't see missing latency fixes for that. Nick's the expert. > I wouldn't have thought it should have become worse, latency wise. What is actually happening is that the lower level freeing functions are being called more often. But this should result in the work being spread out more, if anything. Rather than in the old system things would tend to be batched up into bigger chunks (typically at exit() time). If you are using i386 with 2-level page tables (no highmem), then the behaviour should be more or less identical. Odd. Nick - 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/