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From: Wei Huang <wei.huang2@amd.com>
To: Jan Beulich <JBeulich@novell.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 10:50:48 -0500	[thread overview]
Message-ID: <4DA86958.2090901@amd.com> (raw)
In-Reply-To: <4DA827D9020000780003C9BF@vpn.id2.novell.com>

Will fix.

-Wei
On 04/15/2011 04:11 AM, Jan Beulich wrote:
>>>> 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
>
>

      reply	other threads:[~2011-04-15 15:50 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
2011-04-15 15:50   ` Wei Huang [this message]

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