Date: Wed, 10 Feb 1999 15:42:54 -0800 From: Mike Smith <mike@smith.net.au> To: Tony Finch <dot@dotat.at> Cc: hackers@FreeBSD.ORG Subject: Re: PIPE_BUF Message-ID: <199902102342.PAA01160@dingo.cdrom.com> In-Reply-To: Your message of "Wed, 10 Feb 1999 18:14:08 GMT." <E10Ae9I-0004x0-00@fanf.noc.demon.net>
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> 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.) If it's actually writing into a pipe, it should write as much as possible at once under FreeBSD to get best performance. -- \\ Sometimes you're ahead, \\ Mike Smith \\ sometimes you're behind. \\ mike@smith.net.au \\ The race is long, and in the \\ msmith@freebsd.org \\ end it's only with yourself. \\ msmith@cdrom.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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