From owner-freebsd-hackers Wed Nov 18 10:43:38 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id KAA17749 for freebsd-hackers-outgoing; Wed, 18 Nov 1998 10:43:38 -0800 (PST) (envelope-from owner-freebsd-hackers@FreeBSD.ORG) Received: from apollo.backplane.com (apollo.backplane.com [209.157.86.2]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id KAA17744 for ; Wed, 18 Nov 1998 10:43:34 -0800 (PST) (envelope-from dillon@apollo.backplane.com) Received: (from dillon@localhost) by apollo.backplane.com (8.9.1/8.9.1) id KAA06180; Wed, 18 Nov 1998 10:42:50 -0800 (PST) (envelope-from dillon) Date: Wed, 18 Nov 1998 10:42:50 -0800 (PST) From: Matthew Dillon Message-Id: <199811181842.KAA06180@apollo.backplane.com> To: Marius Bendiksen Cc: Terry Lambert , rnordier@nordier.com, freebsd-hackers@FreeBSD.ORG Subject: Re: FreeBSD on i386 memory model References: <199811171806.LAA03809@usr09.primenet.com> <3.0.5.32.19981118121341.00975ac0@mail.scancall.no> Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG :> Interrupt gates are definitely faster. : :Okay. I seemed to recall it being the other way around. Obtw; are they only :faster upon entry, or do they return quicker, too? On the 386 and 486, call gates are faster. On the pentium, pentium-PRO, and pentium-II, interrupts are faster. Argument copying is wasteful and has limited use on systems where the supervisor has access to the user mode memory map. FreeBSD (and virtually all other operating systems) uses a two-layer design, not a multi-layer ring design. About the only thing you might see different between OS's is that some processors have a separate 'interrupt stack'. On Intel cpu's, however, the abstraction is useless due to the completely broken ring design because many supervisor instructions only work in ring 0. ring 1 and ring 2 are almost completely useless. -Matt :Marius Bendiksen, IT-Trainee, ScanCall AS : Matthew Dillon Engineering, HiWay Technologies, Inc. & BEST Internet Communications & God knows what else. (Please include original email in any response) To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message