Date: Mon, 9 Dec 1996 21:38:50 -0500 (EST) From: "John S. Dyson" <toor@dyson.iquest.net> To: erich@lodgenet.com (Eric L. Hernes) Cc: scrappy@hub.org, hackers@FreeBSD.ORG Subject: Re: Multiple Buffer allocation of Shared Memory Message-ID: <199612100238.VAA27569@dyson.iquest.net> In-Reply-To: <199612100156.TAA00658@jake.lodgenet.com> from "Eric L. Hernes" at Dec 9, 96 07:56:17 pm
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> > Shared memory is cool, SysV symantics for shared memory *suck*, if at all > possible use mmap(). BSDi uses libc wrappers around mmap() for > it's SysV shm stuff, but there's caveats... I'd like the wrappers, > but have the real ones available too. > FreeBSD, NetBSD, and OpenBSD have a low level implementation of the SYSVSHM stuff (not based on mmap, but on some of the low level kernel primatives that are also used to implement mmap.) > > you can only have 8 shm segments by default, you can override > it with: `options "SHMSEG=32"' or something similar in your config file. > I usually bump SHMSEG to 128 and SHMMAXPGS to 4096. > The limits on FreeBSD are totally administrative, and so if you need to increase SHMMAXPGS or somesuch, there is little cost. John dyson@freebsd.org
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