From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from sfi-mx-2.v28.ch3.sourceforge.com ([172.29.28.122] helo=mx.sourceforge.net) by h25xhf1.ch3.sourceforge.com with esmtp (Exim 4.69) (envelope-from ) id 1Lx1uN-0007cc-M8 for user-mode-linux-devel@lists.sourceforge.net; Thu, 23 Apr 2009 16:36:19 +0000 Received: from [198.99.130.12] (helo=saraswathi.solana.com) by 72vjzd1.ch3.sourceforge.com with esmtps (TLSv1:AES256-SHA:256) (Exim 4.69) id 1Lx1uL-0006k3-S8 for user-mode-linux-devel@lists.sourceforge.net; Thu, 23 Apr 2009 16:36:19 +0000 Date: Thu, 23 Apr 2009 12:06:59 -0400 From: Jeff Dike Message-ID: <20090423160659.GD9820@c2.user-mode-linux.org> References: <20090418154021.GA14617@ivl.dyndns.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20090418154021.GA14617@ivl.dyndns.org> Subject: Re: [uml-devel] [Patch] Save FPU registers between task switches List-Id: The user-mode Linux development list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: user-mode-linux-devel-bounces@lists.sourceforge.net To: Ingo van Lil Cc: user-mode-linux-devel@lists.sourceforge.net On Sat, Apr 18, 2009 at 05:40:21PM +0200, Ingo van Lil wrote: > some time ago Jeff prepared a patch [1] for UML to stop saving the > process FP state between task switches. The assumption was that since > with SKAS0 every guest process runs inside a host process context the > host OS will take care of keeping the proper FP state. Unfortunately > this is not true for multi-threaded applications, where all guest > threads share a single host process context yet all may use the FPU on > their own. Although I haven't verified it I suspect things to be even > worse in SKAS3 mode where all guest processes run inside a single host > process. This seems plausible. Does reverting the patch fix any process crashes? Jeff -- Work email - jdike at linux dot intel dot com ------------------------------------------------------------------------------ Stay on top of everything new and different, both inside and around Java (TM) technology - register by April 22, and save $200 on the JavaOne (SM) conference, June 2-5, 2009, San Francisco. 300 plus technical and hands-on sessions. Register today. Use priority code J9JMT32. http://p.sf.net/sfu/p _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel