From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from sc8-sf-mx1-b.sourceforge.net ([10.3.1.11] helo=sc8-sf-mx1.sourceforge.net) by sc8-sf-list1.sourceforge.net with esmtp (Exim 4.30) id 1Ba4K0-0004OU-PR for user-mode-linux-devel@lists.sourceforge.net; Mon, 14 Jun 2004 20:09:12 -0700 Received: from smtp001.mail.ukl.yahoo.com ([217.12.11.32]) by sc8-sf-mx1.sourceforge.net with smtp (Exim 4.30) id 1Ba4K0-00008B-7u for user-mode-linux-devel@lists.sourceforge.net; Mon, 14 Jun 2004 20:09:12 -0700 From: BlaisorBlade References: <200406071949.04220.blaisorblade_spam@yahoo.it> <200406080455.i584tad2023374@ccure.user-mode-linux.org> <200406092305.24447.blaisorblade_spam@yahoo.it> In-Reply-To: <200406092305.24447.blaisorblade_spam@yahoo.it> MIME-Version: 1.0 Content-Disposition: inline Content-Type: text/plain; charset="iso-8859-1" Message-Id: <200406142017.39563.blaisorblade_spam@yahoo.it> Subject: [uml-devel] Re: The SKAS4 patch?? + ideas for 0 context-switch Sender: user-mode-linux-devel-admin@lists.sourceforge.net Errors-To: user-mode-linux-devel-admin@lists.sourceforge.net List-Unsubscribe: , List-Id: The user-mode Linux development list List-Post: List-Help: List-Subscribe: , List-Archive: Date: Mon, 14 Jun 2004 20:17:39 +0200 Content-Transfer-Encoding: quoted-printable To: user-mode-linux-devel@lists.sourceforge.net Alle 23:05, mercoled=EC 9 giugno 2004, BlaisorBlade ha scritto: > > plus using segments will cost you a cycle or something > > on every memory reference. The Intel Manual 3 (Intel System Programming Guide - 253668 -15.pdf) says, = at=20 page 4-1 (page 107 in the PDF), that limit checking has no performance cost= ,=20 and I expect this to hold especially for simply verifying if an address is = below a limit. Maybe it could lie, ok, but maybe Alan Cox was referring to = more complex segmentation tricks. I'm also going to ask to Ingo Molnar (he sets a segment limit in the CS=20 descriptor in his exec-shield patch, so he has probably benchmarked the=20 result). --=20 Paolo Giarrusso, aka Blaisorblade Linux registered user n. 292729 ------------------------------------------------------- This SF.Net email is sponsored by The 2004 JavaOne(SM) Conference Learn from the experts at JavaOne(SM), Sun's Worldwide Java Developer Conference, June 28 - July 1 at the Moscone Center in San Francisco, CA REGISTER AND SAVE! http://java.sun.com/javaone/sf Priority Code NWMGYKND _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel