From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752890AbYKXMRR (ORCPT ); Mon, 24 Nov 2008 07:17:17 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752107AbYKXMRE (ORCPT ); Mon, 24 Nov 2008 07:17:04 -0500 Received: from tomts25.bellnexxia.net ([209.226.175.188]:35333 "EHLO tomts25-srv.bellnexxia.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751939AbYKXMRD (ORCPT ); Mon, 24 Nov 2008 07:17:03 -0500 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AlMFAAAnKklMROB9/2dsb2JhbACBbYEwzHyCfA Date: Mon, 24 Nov 2008 07:16:59 -0500 From: Mathieu Desnoyers To: KOSAKI Motohiro Cc: ltt-dev@lists.casi.polymtl.ca, Ingo Molnar , linux-kernel@vger.kernel.org, William Lee Irwin III Subject: Re: [ltt-dev] [RFC PATCH] Poll : add poll_wait_set_exclusive (fixing thundering herd problem in LTTng) Message-ID: <20081124121659.GA18987@Krystal> References: <20081124203932.26BE.KOSAKI.MOTOHIRO@jp.fujitsu.com> <20081124115134.GA17972@Krystal> <20081124205512.26C1.KOSAKI.MOTOHIRO@jp.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline In-Reply-To: <20081124205512.26C1.KOSAKI.MOTOHIRO@jp.fujitsu.com> X-Editor: vi X-Info: http://krystal.dyndns.org:8080 X-Operating-System: Linux/2.6.21.3-grsec (i686) X-Uptime: 07:16:35 up 7 days, 12:57, 4 users, load average: 0.69, 0.67, 0.64 User-Agent: Mutt/1.5.16 (2007-06-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * KOSAKI Motohiro (kosaki.motohiro@jp.fujitsu.com) wrote: > > > I fully agreed this feature is needed. > > > Actually, I've made similar patch at one years ago. > > > > > > http://marc.info/?l=linux-kernel&m=120257050719087&w=2 > > > > > > > > > but, I have one question. > > > My version have epoll support, but yours donesn't have. > > > Is it intensionally? > > > > > > this is just dumb question, it doesn't mean any objection. > > > > Hrm, actually, your patch seems cleaner than mine, but it adds a branch > > in the standard hotpath, which mine does not do (but I am not sure it is > > such an important optimization...). > > Why do you think poll_wait() is hotpath? > I think sysm_poll() isn't hotpath because it often cause task sleeping. > > > > Is there any reason why your patch > > did not get merged ? > > my patch was developed for a part of mem_notify patch series. > but the mem_notify was naked by akpm. > therefore it lost merging motivation ;-) > > Ingo, I'll rebase and post my patch for -tip tommorow. > Could you please review it? > > > > The only reason I did not make a epoll version is simply because LTTng > > currently does not support it. :) > > thanks. > I understand your original intension. > Great, please CC me on this one so I can integrate it to the LTTng tree. Mathieu -- Mathieu Desnoyers OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68