From: "Jan Beulich" <JBeulich@novell.com>
To: Wei Huang <wei.huang2@amd.com>
Cc: "xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>
Subject: Re: [PATCH][RFC] FPU LWP 3/5: define new FPU interface functions: fpu_save, fpu_restore, fpu_reload
Date: Fri, 15 Apr 2011 10:11:21 +0100 [thread overview]
Message-ID: <4DA827D9020000780003C9BF@vpn.id2.novell.com> (raw)
In-Reply-To: <4DA75B57.404@amd.com>
>>> On 14.04.11 at 22:38, Wei Huang <wei.huang2@amd.com> wrote:
> Current Xen implementation only support lazy FPU reload via CR0.TS. But
> new FPU state isn't always tracked by CR0.TS bit. One example is AMD's
> lightweight profiling. With this patch, Xen calls fpu_save() on vcpu
> which is being scheduled out and fpu_restore() on vcpu which is being
> scheduled in. The nonlazy FPU state is saved and restored in these two
> functions.
This doesn't match the actual patch - only fpu_restore() is being
added to the context switch path, fpu_save() was there already,
saving both lazy and non-lazy state.
> This patch also defines fpu_reload() to handle lazy FPU state when #NM
> is triggered.
>
> Signed-off-by: Wei Huang <wei.huang2@amd.com>
>...
>+/* Restore VCPU's FPU state when the vcpu is scheduled out */
>+void fpu_restore(struct vcpu *v)
The comment ought so say "in" rather than "out".
Jan
next prev parent reply other threads:[~2011-04-15 9:11 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-14 20:38 [PATCH][RFC] FPU LWP 3/5: define new FPU interface functions: fpu_save, fpu_restore, fpu_reload Wei Huang
2011-04-15 9:11 ` Jan Beulich [this message]
2011-04-15 15:50 ` Wei Huang
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