From: Jeremy Fitzhardinge <jeremy@goop.org>
To: Andrew Lutomirski <luto@mit.edu>
Cc: Keir Fraser <keir.xen@gmail.com>,
xen-devel@lists.xensource.com,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Subject: Re: [semi-urgent Xen CS question] Re: git commit 9fd67b4ed0714ab718f1f9bd14c344af336a6df7 (x86-64: Give vvars their own page) breaks Xen PV guests (64-bit).
Date: Wed, 27 Jul 2011 23:07:42 -0700 [thread overview]
Message-ID: <4E30FCAE.4070906@goop.org> (raw)
In-Reply-To: <CAObL_7H9LVaXrXu_-2zOgri2XEVzJaE2VywciG1EJF56NJL0jA@mail.gmail.com>
On 07/27/2011 09:33 PM, Andrew Lutomirski wrote:
> On Sandy Bridge, a null vsyscall takes 373 ns. Without
> VCGF_in_syscall, it's 457 ns. The change causes my little test app to
> get cs == __USER_CS.
Hm, 20% is more noticable than I would hope. What about a regular syscall?
> I suspect that Sandy Bridge is just about the worst case. syscall and
> sysret are amazingly fast on Sandy Bridge.
>
Yes, and one presumes it would only get worse.
J
next prev parent reply other threads:[~2011-07-28 6:07 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-25 15:54 git commit 9fd67b4ed0714ab718f1f9bd14c344af336a6df7 (x86-64: Give vvars their own page) breaks Xen PV guests (64-bit) Konrad Rzeszutek Wilk
2011-07-25 15:54 ` Konrad Rzeszutek Wilk
2011-07-25 16:10 ` Konrad Rzeszutek Wilk
2011-07-25 16:10 ` Konrad Rzeszutek Wilk
2011-07-25 18:10 ` Andrew Lutomirski
2011-07-26 7:18 ` Jan Beulich
2011-07-26 7:18 ` Jan Beulich
2011-07-26 16:18 ` Konrad Rzeszutek Wilk
2011-07-26 16:46 ` Ian Campbell
2011-07-26 19:01 ` Andrew Lutomirski
2011-07-26 20:51 ` Konrad Rzeszutek Wilk
2011-07-26 20:51 ` Konrad Rzeszutek Wilk
2011-07-26 20:55 ` Andrew Lutomirski
2011-07-26 20:55 ` Andrew Lutomirski
2011-07-26 21:06 ` Konrad Rzeszutek Wilk
2011-07-26 21:06 ` Konrad Rzeszutek Wilk
[not found] ` <CAObL_7GpX=f3+tXA4ga6cBB_9VWBe6yVFvon=TzECQs5kcb-ag@mail.gmail.com>
[not found] ` <20110726153220.GA15110@dumpdata.com>
2011-07-26 19:08 ` [semi-urgent Xen CS question] " Andrew Lutomirski
2011-07-26 20:48 ` Keir Fraser
2011-07-26 21:10 ` Andrew Lutomirski
2011-07-26 21:40 ` Andrew Lutomirski
2011-07-26 22:20 ` Keir Fraser
2011-07-26 23:37 ` j.fitz.inge@gmail.com
2011-07-27 2:17 ` Andrew Lutomirski
2011-07-27 15:40 ` Jeremy Fitzhardinge
2011-07-27 16:02 ` Andrew Lutomirski
2011-07-27 17:19 ` Jeremy Fitzhardinge
2011-07-28 4:33 ` Andrew Lutomirski
2011-07-28 6:07 ` Jeremy Fitzhardinge [this message]
2011-07-29 12:51 ` Andrew Lutomirski
2011-07-29 15:31 ` Jeremy Fitzhardinge
2011-07-31 18:56 ` Konrad Rzeszutek Wilk
2011-07-31 19:14 ` Andrew Lutomirski
2011-08-02 14:10 ` Konrad Rzeszutek Wilk
2011-07-27 12:57 ` Konrad Rzeszutek Wilk
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