Date: Wed, 24 Jun 1998 20:56:32 +1000 From: Stephen McKay <syssgm@dtir.qld.gov.au> To: Bruce Evans <bde@zeta.org.au> Cc: freebsd-current@FreeBSD.ORG, syssgm@dtir.qld.gov.au Subject: Re: PIPE_BUF? Message-ID: <199806241056.UAA15554@nymph.dtir.qld.gov.au> In-Reply-To: <199806100123.LAA06267@godzilla.zeta.org.au> from Bruce Evans at "Wed, 10 Jun 1998 11:23:04 %2B1000" References: <199806100123.LAA06267@godzilla.zeta.org.au>
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On Wednesday, 10th June 1998, Bruce Evans wrote: >>>From sys/syslimits.h: >> >>#define PIPE_BUF 512 /* max bytes for atomic pipe >>writes */ ^^^ >> >>Is it still true? If not, we should change it to _real_ value since some >>software (like apache) depends on it. > >Yes. In 2.2, it really shouldn't be defined, since the max differs for >ordinary pipes (they use PIPE_MAX = 512) and fifos (they use the default >socket sb_lowat = MCLBYTES = 2048)... No matter how much you know, there are always surprises... How much would it hurt performance or whatever in the normal case (ie don't care about atomicity because there's just 1 sender and 1 receiver) to raise this to at least a page (4Kb). After all, years ago the limit was 5Kb (and still 5Kb for System V). This is something that has gone backwards on BSD! Stephen. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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