From owner-cvs-all Thu Nov 12 11:47:08 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id LAA13431 for cvs-all-outgoing; Thu, 12 Nov 1998 11:47:08 -0800 (PST) (envelope-from owner-cvs-all@FreeBSD.ORG) Received: from ganymede.or.intel.com (ganymede.or.intel.com [134.134.248.3]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id LAA13424 for ; Thu, 12 Nov 1998 11:47:06 -0800 (PST) (envelope-from wscott@ichips.intel.com) Received: from ichips-jf.jf.intel.com (ichips-jf.jf.intel.com [134.134.50.200]) by ganymede.or.intel.com (8.8.6/8.8.5) with ESMTP id TAA25414; Thu, 12 Nov 1998 19:46:48 GMT Received: from pdxlx008.pdx.intel.com (pdxlx008.pdx.intel.com [137.102.206.194]) by ichips-jf.jf.intel.com (8.8.8/8.8.7) with ESMTP id LAA29077; Thu, 12 Nov 1998 11:46:47 -0800 (PST) Received: from pdxlx008.pdx.intel.com (localhost [127.0.0.1]) by pdxlx008.pdx.intel.com (8.8.7/8.8.7) with ESMTP id LAA02237; Thu, 12 Nov 1998 11:46:47 -0800 (PST) (envelope-from wscott@pdxlx008.pdx.intel.com) Message-Id: <199811121946.LAA02237@pdxlx008.pdx.intel.com> To: cvs-all@FreeBSD.ORG Cc: mike@smith.net.au Subject: Re: sendfile.2 (was Re: cvs commit: ...) In-reply-to: Your message of "Fri, 06 Nov 1998 20:14:49 PST." <199811070414.UAA21183@hub.freebsd.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Date: Thu, 12 Nov 1998 11:46:46 -0800 From: Wayne Scott Sender: owner-cvs-all@FreeBSD.ORG Precedence: bulk > That's about consistent with expectations; context switch from one > process context to another is about as fast as it can be. Crossing the > user:kernel protection boundary is not so easy - one of the major > shortcomings of the i386 architecture it seems. > Read the info on the SYSENTER instruction. Intel is finally documenting it properly. http://developer.intel.com/design/pentiumii/manuals/243689.htm It is an ugly hack, but you can switch from user to kernel twice as fast as other methods. (PII only unfortunatly) -Wayne Wayne Scott MD6 Architecture - Intel Corp. wscott@ichips.intel.com Work #: (503) 613-5063 Disclaimer: All views expressed are my own opinions, and not necessarily those of Intel Corporation. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message