From owner-freebsd-current Tue Aug 25 18:56:12 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id SAA21265 for freebsd-current-outgoing; Tue, 25 Aug 1998 18:56:12 -0700 (PDT) (envelope-from owner-freebsd-current@FreeBSD.ORG) Received: from smtp04.primenet.com (smtp04.primenet.com [206.165.6.134]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id SAA21257; Tue, 25 Aug 1998 18:56:05 -0700 (PDT) (envelope-from tlambert@usr04.primenet.com) Received: (from daemon@localhost) by smtp04.primenet.com (8.8.8/8.8.8) id SAA29858; Tue, 25 Aug 1998 18:55:13 -0700 (MST) Received: from usr04.primenet.com(206.165.6.204) via SMTP by smtp04.primenet.com, id smtpd029847; Tue Aug 25 18:55:10 1998 Received: (from tlambert@localhost) by usr04.primenet.com (8.8.5/8.8.5) id SAA00915; Tue, 25 Aug 1998 18:55:00 -0700 (MST) From: Terry Lambert Message-Id: <199808260155.SAA00915@usr04.primenet.com> Subject: Re: Threads across processors To: mike@smith.net.au (Mike Smith) Date: Wed, 26 Aug 1998 01:55:00 +0000 (GMT) Cc: michaelh@cet.co.jp, gpalmer@FreeBSD.ORG, chuckr@glue.umd.edu, freebsd-current@FreeBSD.ORG In-Reply-To: <199808251338.NAA02533@dingo.cdrom.com> from "Mike Smith" at Aug 25, 98 01:38:18 pm X-Mailer: ELM [version 2.4 PL25] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG > > Our pipes are very fast. SYSV SHM's blunder is that it uses full blown > > system calls for synchronization. > > Yes. Anyone that thinks in terms of a context switch per transaction > between coprocesses is not designing properly. Using a shared mmap() > region and datastructures that don't require locking is another > cost-effective technique. A dirty little secret is that SYSV SHM in FreeBSD is much faster than mmap, because pages backed by anonymous pages instead of a vnode pager object do not have to be written through... Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message