Return-Path: Delivered-To: apmail-httpd-dev-archive@www.apache.org Received: (qmail 11053 invoked from network); 6 Dec 2004 22:29:37 -0000 Received: from hermes.apache.org (HELO mail.apache.org) (209.237.227.199) by minotaur-2.apache.org with SMTP; 6 Dec 2004 22:29:37 -0000 Received: (qmail 48637 invoked by uid 500); 6 Dec 2004 22:29:30 -0000 Delivered-To: apmail-httpd-dev-archive@httpd.apache.org Received: (qmail 48612 invoked by uid 500); 6 Dec 2004 22:29:30 -0000 Mailing-List: contact dev-help@httpd.apache.org; run by ezmlm Precedence: bulk Reply-To: dev@httpd.apache.org list-help: list-unsubscribe: list-post: Delivered-To: mailing list dev@httpd.apache.org Received: (qmail 48597 invoked by uid 99); 6 Dec 2004 22:29:30 -0000 X-ASF-Spam-Status: No, hits=0.0 required=10.0 tests= X-Spam-Check-By: apache.org Received-SPF: neutral (hermes.apache.org: local policy) Received: from bsl-rtr.day.com (HELO picanmix.dev.day.com) (212.249.34.130) by apache.org (qpsmtpd/0.28) with ESMTP; Mon, 06 Dec 2004 14:29:29 -0800 Received: from eu-mail.day.com (eu-mail.dev.day.com [10.0.0.30]) by picanmix.dev.day.com (DAY) with ESMTP id iB6MTPV16532 for ; Mon, 6 Dec 2004 23:29:26 +0100 (MET) Received: from [10.2.8.58] ([10.2.8.58]) by eu-mail.day.com (Lotus Domino Release 5.0.8) with ESMTP id 2004120623292468:2295 ; Mon, 6 Dec 2004 23:29:24 +0100 Mime-Version: 1.0 (Apple Message framework v619) In-Reply-To: <41B37684.2060506@force-elite.com> References: <20041205070523.69174.qmail@minotaur.apache.org> <20041205134744.GA10093@redhat.com> <41B37684.2060506@force-elite.com> Message-Id: <48C3FF89-47D6-11D9-A270-000D93324AD6@gbiv.com> From: "Roy T. Fielding" Subject: Re: svn commit: r109866 - /httpd/httpd/trunk/modules/loggers/mod_log_config.c Date: Mon, 6 Dec 2004 14:29:25 -0800 To: dev@httpd.apache.org X-Mailer: Apple Mail (2.619) X-MIMETrack: Itemize by SMTP Server on eu-mail/Day(Release 5.0.8 |June 18, 2001) at 12/06/2004 11:29:24 PM, Serialize by Router on eu-mail/Day(Release 5.0.8 |June 18, 2001) at 12/06/2004 11:29:26 PM, Serialize complete at 12/06/2004 11:29:26 PM Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=US-ASCII; format=flowed X-Virus-Checked: Checked X-Spam-Rating: minotaur-2.apache.org 1.6.2 0/1000/N -1 (veto) -- the message is copied to a single buffer for the write because that is the only way to guarantee an atomic append under Unix without locks, thus preventing multiple children from scribbling over each other's log entries. Please revert this change ASAP. ....Roy On Dec 5, 2004, at 12:58 PM, Paul Querna wrote: > Joe Orton wrote: >> On Sun, Dec 05, 2004 at 07:05:23AM -0000, Paul Querna wrote: >>> Author: pquerna >>> Date: Sat Dec 4 23:05:23 2004 >>> New Revision: 109866 >>> >>> URL: http://svn.apache.org/viewcvs?view=rev&rev=109866 >>> Log: >>> mod_log_config.c: Use iovecs to write the log line to eliminate a >>> memcpy >> IIRC, writev'ing several small blocks to a file is actually generally >> more expensive than doing a memcpy in userspace and calling write. >> Did >> you benchmark this to be faster/better/...? > > I did a local mini-benchmark of write w/ memcpy vs writev... and they > came out to almost exactly the same on average with small sets of > data. > > -Paul > >