From: Keir Fraser <keir@xen.org>
To: Jan Beulich <JBeulich@suse.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
xen-devel <xen-devel@lists.xen.org>
Subject: Re: fpu_taskswitch adjustment proposal
Date: Mon, 18 Jun 2012 13:12:56 +0100 [thread overview]
Message-ID: <CC04D9D8.431BE%keir@xen.org> (raw)
In-Reply-To: <4FDEF595020000780008A5B7@nat28.tlf.novell.com>
On 18/06/2012 08:32, "Jan Beulich" <JBeulich@suse.com> wrote:
>> It should be possible for the guest kernel to track its CR0.TS setting
>> shouldn't it? It gets modified only via a few paravirt hooks, and implicitly
>> cleared on #NM.
>
> Sure, but selling this to the Linux maintainers I would expect to be
> harder than fitting the Xen side of things into the current save-
> and-restore model the native xor code uses. It would only be strait
> forward to implement on the legacy, forward ported trees.
Wouldn't it be hidden entirely behind pv_ops hooks and within Xen-specific
SSE save/restore code? I suppose you'd need to statically allocate the
per-cpu space for tracking the CR0.TS state... But overall it seems it will
be of little/no concern to other kernel maintainers?
-- Keir
> However, with the #NM handler in pv-ops apparently not
> leveraging the fact that CR0.TS is already cleared for it on entry,
> maybe this could indeed be introduced together. Konrad?
next prev parent reply other threads:[~2012-06-18 12:12 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-15 16:03 fpu_taskswitch adjustment proposal Jan Beulich
2012-06-15 17:06 ` Keir Fraser
2012-06-18 7:32 ` Jan Beulich
2012-06-18 12:12 ` Keir Fraser [this message]
2012-06-18 12:45 ` Jan Beulich
2012-06-18 13:59 ` Keir Fraser
2012-06-18 18:24 ` Konrad Rzeszutek Wilk
2012-06-18 22:35 ` Keir Fraser
2012-06-26 16:25 ` Jan Beulich
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