From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S937799AbXGTWjj (ORCPT ); Fri, 20 Jul 2007 18:39:39 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752815AbXGTWjc (ORCPT ); Fri, 20 Jul 2007 18:39:32 -0400 Received: from zcars04e.nortel.com ([47.129.242.56]:56335 "EHLO zcars04e.nortel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751524AbXGTWjb (ORCPT ); Fri, 20 Jul 2007 18:39:31 -0400 Message-ID: <46A1399C.8010405@nortel.com> Date: Fri, 20 Jul 2007 16:39:24 -0600 From: "Chris Friesen" User-Agent: Mozilla Thunderbird 1.0.2-6 (X11/20050513) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Lee Revell CC: linux-kernel@vger.kernel.org Subject: Re: posible latency issues in seq_read References: <46A125F4.3030504@nortel.com> <75b66ecd0707201518j45ef8bb7q7e48462ffbbc9c58@mail.gmail.com> In-Reply-To: <75b66ecd0707201518j45ef8bb7q7e48462ffbbc9c58@mail.gmail.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 20 Jul 2007 22:39:27.0614 (UTC) FILETIME=[D46429E0:01C7CB1E] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Lee Revell wrote: > On 7/20/07, Chris Friesen wrote: >> We've run into an issue (on 2.6.10) where calling "lsof" triggers lost >> packets on our server. Preempt is disabled, and NAPI is enabled. > Can you reproduce with a recent kernel? Lots of latency issues have > been fixed since then. Unfortunately I have to fix it on this version (the bug was found on shipped product), so if there was a difference I'd have to isolate the changes and backport them. Also, I can't run the software that triggers the problem on a newer kernel as it has dependencies on various patches that are not in mainline. Basically what I'd like to know is whether calling schedule() in seq_read() is safe or whether it would break assumptions made by seq_file users. Chris