From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261240AbVGKIgy (ORCPT ); Mon, 11 Jul 2005 04:36:54 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261390AbVGKIgy (ORCPT ); Mon, 11 Jul 2005 04:36:54 -0400 Received: from smtp.nedstat.nl ([194.109.98.184]:24520 "HELO smtp.nedstat.nl") by vger.kernel.org with SMTP id S261240AbVGKIgx (ORCPT ); Mon, 11 Jul 2005 04:36:53 -0400 Subject: Re: [PATCH] eventpoll : Suppress a short lived lock from struct file From: Peter Zijlstra To: Eric Dumazet Cc: Linux Kernel Mailing List , Davide Libenzi In-Reply-To: <42D21D43.3060300@cosmosbay.com> References: <4263275A.2020405@lab.ntt.co.jp> <20050418040718.GA31163@taniwha.stupidest.org> <4263356D.9080007@lab.ntt.co.jp> <20050418044223.GB15002@nevyn.them.org> <1113800136.355.1.camel@localhost.localdomain> <42D21D43.3060300@cosmosbay.com> Content-Type: text/plain Date: Mon, 11 Jul 2005 10:34:27 +0200 Message-Id: <1121070867.24086.6.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.2.2 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2005-07-11 at 09:18 +0200, Eric Dumazet wrote: > Hi Davide > > I found in my tests that there is no need to have a f_ep_lock spinlock > attached to each struct file, using 8 bytes on 64bits platforms. The > lock is hold for a very short time period and can be global, with almost > no change in performance for applications using epoll, and a gain for > all others. > Have you tested the impact of this change on big SMP/NUMA machines? I hate to see an Altrix crashing to its knees :-) -- Peter Zijlstra