From owner-freebsd-current Wed Jun 24 03:57:22 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id DAA02319 for freebsd-current-outgoing; Wed, 24 Jun 1998 03:57:22 -0700 (PDT) (envelope-from owner-freebsd-current@FreeBSD.ORG) Received: from ren.dtir.qld.gov.au (firewall-user@ns.dtir.qld.gov.au [203.108.138.66]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id DAA02289 for ; Wed, 24 Jun 1998 03:57:10 -0700 (PDT) (envelope-from syssgm@dtir.qld.gov.au) Received: by ren.dtir.qld.gov.au; id UAA21007; Wed, 24 Jun 1998 20:56:46 +1000 (EST) Received: from ogre.dtir.qld.gov.au(167.123.8.3) by ren.dtir.qld.gov.au via smap (3.2) id xma021005; Wed, 24 Jun 98 20:56:35 +1000 Received: from atlas.dtir.qld.gov.au (atlas.dtir.qld.gov.au [167.123.8.9]) by ogre.dtir.qld.gov.au (8.8.8/8.8.7) with ESMTP id UAA12218; Wed, 24 Jun 1998 20:56:34 +1000 (EST) Received: from nymph.dtir.qld.gov.au (nymph.dtir.qld.gov.au [167.123.10.10]) by atlas.dtir.qld.gov.au (8.8.5/8.8.5) with ESMTP id UAA07171; Wed, 24 Jun 1998 20:56:34 +1000 (EST) Received: from nymph.dtir.qld.gov.au (localhost.dtir.qld.gov.au [127.0.0.1]) by nymph.dtir.qld.gov.au (8.8.8/8.8.7) with ESMTP id UAA15554; Wed, 24 Jun 1998 20:56:32 +1000 (EST) (envelope-from syssgm@nymph.dtir.qld.gov.au) Message-Id: <199806241056.UAA15554@nymph.dtir.qld.gov.au> To: Bruce Evans cc: freebsd-current@FreeBSD.ORG, syssgm@dtir.qld.gov.au Subject: Re: PIPE_BUF? References: <199806100123.LAA06267@godzilla.zeta.org.au> In-Reply-To: <199806100123.LAA06267@godzilla.zeta.org.au> from Bruce Evans at "Wed, 10 Jun 1998 11:23:04 +1000" Date: Wed, 24 Jun 1998 20:56:32 +1000 From: Stephen McKay Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG 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