From owner-freebsd-hackers Sat Feb 13 06:34:02 1999 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id GAA11506 for freebsd-hackers-outgoing; Sat, 13 Feb 1999 06:34:02 -0800 (PST) (envelope-from owner-freebsd-hackers@FreeBSD.ORG) Received: from server.noc.demon.net (server.noc.demon.net [193.195.224.4]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id GAA11485 for ; Sat, 13 Feb 1999 06:33:57 -0800 (PST) (envelope-from fanf@demon.net) Received: by server.noc.demon.net; id OAA21754; Sat, 13 Feb 1999 14:33:55 GMT Received: from fanf.noc.demon.net(195.11.55.83) by inside.noc.demon.net via smap (3.2) id xma021732; Sat, 13 Feb 99 14:33:52 GMT Received: from fanf by fanf.noc.demon.net with local (Exim 1.73 #2) id 10Bg8l-0007WQ-00; Sat, 13 Feb 1999 14:33:51 +0000 To: hackers@FreeBSD.ORG From: Tony Finch Subject: Re: PIPE_BUF In-Reply-To: <199902102342.PAA01160@dingo.cdrom.com> References: Message-Id: Date: Sat, 13 Feb 1999 14:33:51 +0000 Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG Mike Smith wrote: >> I've been looking at the Apache code for doing buffered writes to >> logs, which it attempts to do in such a way that log records are not >> split across buffer boundaries. It therefore buffers up to PIPE_BUF >> bytes to be written in one go. > >If it's actually writing into a pipe, it should write as much as >possible at once under FreeBSD to get best performance. How likely am I to fall foul of concurrency issues when doing that? The reason Apache does what it does is to avoid writes from different httpds to the same pipe getting confused with each other. Why should a large PIPE_BUF have a bad effect on interactive pipes? Is it simply because of the way stdio buffers writes? Tony. -- f.a.n.finch dot@dotat.at fanf@demon.net To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message