Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754610Ab0HZXCT (ORCPT ); Thu, 26 Aug 2010 19:02:19 -0400 Received: from www.tglx.de ([62.245.132.106]:48489 "EHLO www.tglx.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752464Ab0HZXCR (ORCPT ); Thu, 26 Aug 2010 19:02:17 -0400 Date: Fri, 27 Aug 2010 01:02:09 +0200 (CEST) From: Thomas Gleixner To: Davide Libenzi cc: Shawn Bohrer , Alexander Viro , linux-fsdevel@vger.kernel.org, Linux Kernel Mailing List , Arjan van de Ven Subject: Re: [PATCH] hrtimer: make epoll_wait() use the hrtimer range feature In-Reply-To: Message-ID: References: User-Agent: Alpine 2.00 (LFD 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1036 Lines: 36 On Thu, 26 Aug 2010, Davide Libenzi wrote: > On Sun, 8 Aug 2010, Shawn Bohrer wrote: > > > This make epoll use hrtimers for the timeout value which prevents > > epoll_wait() from timing out up to a millisecond early. > > > > This mirrors the behavior of select() and poll(). > > I saw this now, since I got notifications from Andrew's patch machine. > Is this really needed? Yes, as it is the last user space interface which is jiffies based. > Is that really worth the extra code in the fast path? It's not that much overhead and we had no complaints when we converted everything else > Aren't we breaking existing behavior? We had no problems when we moved all the other interfaces over > I have some doubts. /me not - though I need to look at the patch itself Thanks, tglx -- 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/