From: Jeff Dike <jdike@addtoit.com>
To: Ingo van Lil <inguin@gmx.de>
Cc: user-mode-linux-devel@lists.sourceforge.net
Subject: Re: [uml-devel] [Patch] Save FPU registers between task switches
Date: Thu, 23 Apr 2009 12:06:59 -0400 [thread overview]
Message-ID: <20090423160659.GD9820@c2.user-mode-linux.org> (raw)
In-Reply-To: <20090418154021.GA14617@ivl.dyndns.org>
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
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next prev parent reply other threads:[~2009-04-23 16:36 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-18 15:40 [uml-devel] [Patch] Save FPU registers between task switches Ingo van Lil
2009-04-23 16:06 ` Jeff Dike [this message]
2009-04-23 16:38 ` Ingo van Lil
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