From: Anthony Liguori <anthony@codemonkey.ws>
To: Avi Kivity <avi@redhat.com>
Cc: Anthony Liguori <aliguori@us.ibm.com>, Jes Sorensen <jes@sgi.com>,
qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [patch 2/2] QEMU BOCHS bios patches to use maxcpus value.
Date: Sun, 12 Jul 2009 08:23:45 -0500 [thread overview]
Message-ID: <4A59E3E1.30406@codemonkey.ws> (raw)
In-Reply-To: <4A59AF3C.8030005@redhat.com>
Avi Kivity wrote:
> On 07/10/2009 12:57 AM, Anthony Liguori wrote:
>> These changes make my Ubuntu server guest very unhappy. I get a
>> bunch of messages about "Not responding." on startup.
>>
>> If nothing else, maxcpus ==smp_cpus under QEMU because we don't do
>> CPU hotplug (and I don't think we should).
>>
>
> Why shouldn't we do cpu hotplug?
I don't think we should do cpu hotplug via ACPI. I don't think ACPI
actually models CPU hotplug and the fact that this works with Linux in
KVM is a happy accident. VMware only supports CPU hotplug for Windows
7/2k8 guests so I'm assuming their using Viridian PV extensions to do it.
I think we should go the PV route for Linux too. I'd rather see us
create all vcpu threads at once and then let the guest offline each vcpu
via a PV notification. I don't see a lot of value in
spawning/terminating vcpu threads dynamically and it adds an awful lot
of complexity. There's very little overhead to an idle thread.
Regards,
Anthony Liguori
next prev parent reply other threads:[~2009-07-12 13:23 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-06-24 8:35 [Qemu-devel] [patch 0/2] QEMU maxcpus support v2 Jes Sorensen
2009-06-24 8:35 ` [Qemu-devel] [patch 1/2] Introduce -smp , maxcpus= flag to specify maximum number of CPUS Jes Sorensen
2009-06-24 9:02 ` [Qemu-devel] " Avi Kivity
2009-06-24 9:02 ` Jes Sorensen
2009-06-24 9:15 ` Avi Kivity
2009-06-24 12:04 ` Jes Sorensen
2009-06-24 8:35 ` [Qemu-devel] [patch 2/2] QEMU BOCHS bios patches to use maxcpus value Jes Sorensen
2009-07-09 21:57 ` Anthony Liguori
2009-07-12 9:39 ` Avi Kivity
2009-07-12 13:23 ` Anthony Liguori [this message]
2009-07-12 13:36 ` Avi Kivity
2009-07-14 8:38 ` Jes Sorensen
2009-07-14 9:21 ` Filip Navara
2009-07-14 9:32 ` Gleb Natapov
2009-07-14 10:16 ` Alexander Graf
2009-07-14 11:15 ` Filip Navara
2009-07-14 11:21 ` Jes Sorensen
-- strict thread matches above, loose matches on Subject: below --
2009-07-23 15:03 [Qemu-devel] [PATCH 0/2] QEMU maxcpus support v4 Jes Sorensen
2009-07-23 15:03 ` [Qemu-devel] [PATCH 2/2] QEMU BOCHS bios patches to use maxcpus value Jes Sorensen
2009-07-20 14:43 [Qemu-devel] [PATCH 0/2] QEMU maxcpus support v3 Jes Sorensen
2009-07-20 14:43 ` [Qemu-devel] [PATCH 2/2] QEMU BOCHS bios patches to use maxcpus value Jes Sorensen
2009-07-14 12:53 [Qemu-devel] [PATCH 0/2] QEMU maxcpus support v2 Jes Sorensen
2009-07-14 12:53 ` [Qemu-devel] [PATCH 2/2] QEMU BOCHS bios patches to use maxcpus value Jes Sorensen
2009-06-23 10:00 [Qemu-devel] [patch 0/2] QEMU maxcpus support Jes Sorensen
2009-06-23 10:00 ` [Qemu-devel] [patch 2/2] QEMU BOCHS bios patches to use maxcpus value Jes Sorensen
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