From owner-freebsd-hackers Wed Feb 10 10:14:30 1999 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id KAA28870 for freebsd-hackers-outgoing; Wed, 10 Feb 1999 10:14:30 -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 KAA28865 for ; Wed, 10 Feb 1999 10:14:28 -0800 (PST) (envelope-from fanf@demon.net) Received: by server.noc.demon.net; id SAA29585; Wed, 10 Feb 1999 18:14:22 GMT Received: from fanf.noc.demon.net(195.11.55.83) by inside.noc.demon.net via smap (3.2) id xma029574; Wed, 10 Feb 99 18:14:09 GMT Received: from fanf by fanf.noc.demon.net with local (Exim 1.73 #2) id 10Ae9I-0004x0-00; Wed, 10 Feb 1999 18:14:08 +0000 To: hackers@FreeBSD.ORG From: Tony Finch Subject: PIPE_BUF Message-Id: Date: Wed, 10 Feb 1999 18:14:08 +0000 Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG 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. Unfortunately, on FreeBSD this doesn't win us much because our log format averages over 200 bytes and PIPE_BUF is only 512 bytes, so we'll only be writing at most a couple of records at a time. Other systems have PIPE_BUF sizes like 4K (Linux), 5K (Solaris), and 10K (IRIX). What do I need to worry about if I rebuild the system with a bigger PIPE_BUF? (Actually, I don't really care about the buffer boundary thing so if changing PIPE_BUF is painful I'll just compile Apache to use a bigger buffer regardless of PIPE_BUF.) 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