From: Boris Ostrovsky <boris.ostrovsky@oracle.com>
To: Juergen Gross <jgross@suse.com>,
Dario Faggioli <dario.faggioli@citrix.com>
Cc: Elena Ufimtseva <elena.ufimtseva@oracle.com>,
Wei Liu <wei.liu2@citrix.com>,
Andrew Cooper <andrew.cooper3@citrix.com>,
David Vrabel <david.vrabel@citrix.com>,
Jan Beulich <JBeulich@suse.com>,
"xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>
Subject: Re: PV-vNUMA issue: topology is misinterpreted by the guest
Date: Fri, 24 Jul 2015 12:40:50 -0400 [thread overview]
Message-ID: <55B26A92.8060004@oracle.com> (raw)
In-Reply-To: <55B26377.4060807@suse.com>
On 07/24/2015 12:10 PM, Juergen Gross wrote:
>
> If we can fiddle with the masks on boot, we could do it in a running
> system, too. Another advantage with not relying on cpuid. :-)
I am trying to catch up with this thread so I may have missed it, but I
still don't understand why we don't want to rely on CPUID.
I think I saw Juergen said --- because it's HW-specific. But what's
wrong with that? Hypervisor is building virtualized x86 (in this case)
hardware and on such HW CPUID is the standard way of determining
thread/core topology. Plus various ACPI tables and such.
And having a solution that doesn't address userspace (when there *is* a
solution that can do it) doesn't seem like the best approach. Yes, it
still won't cover userspace for PV guests but neither will the kernel patch.
As far as licensing is concerned --- are we sure this can't also be
addressed by CPUID? BTW, if I was asked about who is most concerned
about licensing my first answer would be --- databases. I.e. userspace.
(Also, I don't know whether this is still true but in the past APICID
format was also used for topology discovery. Just to make things a bit
more interesting ;-))
-boris
next prev parent reply other threads:[~2015-07-24 16:41 UTC|newest]
Thread overview: 95+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-16 10:32 PV-vNUMA issue: topology is misinterpreted by the guest Dario Faggioli
2015-07-16 10:47 ` Jan Beulich
2015-07-16 10:56 ` Andrew Cooper
2015-07-16 15:25 ` Wei Liu
2015-07-16 15:45 ` Andrew Cooper
2015-07-16 15:50 ` Boris Ostrovsky
2015-07-16 16:29 ` Jan Beulich
2015-07-16 16:39 ` Andrew Cooper
2015-07-16 16:59 ` Boris Ostrovsky
2015-07-17 6:09 ` Jan Beulich
2015-07-17 7:27 ` Dario Faggioli
2015-07-17 7:42 ` Jan Beulich
2015-07-17 8:44 ` Wei Liu
2015-07-17 18:17 ` Boris Ostrovsky
2015-07-20 14:09 ` Dario Faggioli
2015-07-20 14:43 ` Boris Ostrovsky
2015-07-21 20:00 ` Boris Ostrovsky
2015-07-22 13:36 ` Dario Faggioli
2015-07-22 13:50 ` Juergen Gross
2015-07-22 13:58 ` Boris Ostrovsky
2015-07-22 14:09 ` Juergen Gross
2015-07-22 14:44 ` Boris Ostrovsky
2015-07-23 4:43 ` Juergen Gross
2015-07-23 7:28 ` Jan Beulich
2015-07-23 9:42 ` Andrew Cooper
2015-07-23 14:07 ` Dario Faggioli
2015-07-23 14:13 ` Juergen Gross
2015-07-24 10:28 ` Juergen Gross
2015-07-24 14:44 ` Dario Faggioli
2015-07-24 15:14 ` Juergen Gross
2015-07-24 15:24 ` Juergen Gross
2015-07-24 15:58 ` Dario Faggioli
2015-07-24 16:09 ` Konrad Rzeszutek Wilk
2015-07-24 16:14 ` Dario Faggioli
2015-07-24 16:18 ` Juergen Gross
2015-07-24 16:29 ` Konrad Rzeszutek Wilk
2015-07-24 16:39 ` Juergen Gross
2015-07-24 16:44 ` Boris Ostrovsky
2015-07-27 4:35 ` Juergen Gross
2015-07-27 10:43 ` George Dunlap
2015-07-27 10:54 ` Andrew Cooper
2015-07-27 11:13 ` Juergen Gross
2015-07-27 10:54 ` Juergen Gross
2015-07-27 11:11 ` George Dunlap
2015-07-27 12:01 ` Juergen Gross
2015-07-27 12:16 ` Tim Deegan
2015-07-27 13:23 ` Dario Faggioli
2015-07-27 14:02 ` Juergen Gross
2015-07-27 14:02 ` Dario Faggioli
2015-07-27 10:41 ` George Dunlap
2015-07-27 10:49 ` Andrew Cooper
2015-07-27 13:11 ` Dario Faggioli
2015-07-24 16:10 ` Juergen Gross
2015-07-24 16:40 ` Boris Ostrovsky [this message]
2015-07-24 16:48 ` Juergen Gross
2015-07-24 17:11 ` Boris Ostrovsky
2015-07-27 13:40 ` Dario Faggioli
2015-07-27 4:24 ` Juergen Gross
2015-07-27 14:09 ` Dario Faggioli
2015-07-27 14:34 ` Boris Ostrovsky
2015-07-27 14:43 ` Juergen Gross
2015-07-27 14:51 ` Boris Ostrovsky
2015-07-27 15:03 ` Juergen Gross
2015-07-27 14:47 ` Juergen Gross
2015-07-27 14:58 ` Dario Faggioli
2015-07-28 4:29 ` Juergen Gross
2015-07-28 15:11 ` Juergen Gross
2015-07-28 16:17 ` Dario Faggioli
2015-07-28 17:13 ` Dario Faggioli
2015-07-29 6:04 ` Juergen Gross
2015-07-29 7:09 ` Dario Faggioli
2015-07-29 7:44 ` Dario Faggioli
2015-07-24 16:05 ` Dario Faggioli
2015-07-28 10:05 ` Wei Liu
2015-07-28 15:17 ` Dario Faggioli
2015-07-24 20:27 ` Elena Ufimtseva
2015-07-22 14:50 ` Dario Faggioli
2015-07-22 15:32 ` Boris Ostrovsky
2015-07-22 15:49 ` Dario Faggioli
2015-07-22 18:10 ` Boris Ostrovsky
2015-07-23 7:25 ` Jan Beulich
2015-07-24 16:03 ` Boris Ostrovsky
2015-07-23 13:46 ` Dario Faggioli
2015-07-17 10:17 ` Andrew Cooper
2015-07-16 15:26 ` Wei Liu
2015-07-27 15:13 ` David Vrabel
2015-07-27 16:02 ` Dario Faggioli
2015-07-27 16:31 ` David Vrabel
2015-07-27 16:33 ` Andrew Cooper
2015-07-27 17:42 ` Dario Faggioli
2015-07-27 17:50 ` Konrad Rzeszutek Wilk
2015-07-27 23:19 ` Andrew Cooper
2015-07-28 3:52 ` Juergen Gross
2015-07-28 9:40 ` Andrew Cooper
2015-07-28 9:28 ` Dario Faggioli
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