* [Qemu-devel] How can I understand CONFIG_IO_THREAD ?
@ 2011-02-21 3:13 wang sheng
2011-02-21 8:16 ` [Qemu-devel] " Paolo Bonzini
0 siblings, 1 reply; 3+ messages in thread
From: wang sheng @ 2011-02-21 3:13 UTC (permalink / raw)
To: qemu-devel
What is the purpose of io_thread desigment in qemu ?
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Qemu-devel] Re: How can I understand CONFIG_IO_THREAD ?
2011-02-21 3:13 [Qemu-devel] How can I understand CONFIG_IO_THREAD ? wang sheng
@ 2011-02-21 8:16 ` Paolo Bonzini
2011-02-21 9:29 ` Avi Kivity
0 siblings, 1 reply; 3+ messages in thread
From: Paolo Bonzini @ 2011-02-21 8:16 UTC (permalink / raw)
To: wang sheng; +Cc: qemu-devel
On 02/21/2011 04:13 AM, wang sheng wrote:
> What is the purpose of io_thread desigment in qemu ?
There was a lengthy thread recently explaining how it helps fixing a
possibly delay in handling I/O. It is also useful for KVM, where you
have one I/O thread and multiple CPU threads. This way, KVM can
implement "real" SMP (i.e. multiple virtual CPUs running concurrently).
Paolo
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [Qemu-devel] Re: How can I understand CONFIG_IO_THREAD ?
2011-02-21 8:16 ` [Qemu-devel] " Paolo Bonzini
@ 2011-02-21 9:29 ` Avi Kivity
0 siblings, 0 replies; 3+ messages in thread
From: Avi Kivity @ 2011-02-21 9:29 UTC (permalink / raw)
To: Paolo Bonzini; +Cc: wang sheng, qemu-devel
On 02/21/2011 10:16 AM, Paolo Bonzini wrote:
> On 02/21/2011 04:13 AM, wang sheng wrote:
>> What is the purpose of io_thread desigment in qemu ?
>
> There was a lengthy thread recently explaining how it helps fixing a
> possibly delay in handling I/O. It is also useful for KVM, where you
> have one I/O thread and multiple CPU threads. This way, KVM can
> implement "real" SMP (i.e. multiple virtual CPUs running concurrently).
>
In fact kvm smp was available even before the iothread; one thread
handled both vcpu 0 and I/O completions, while the other threads only
handled a vcpu each. Later, the first thread was split into an iothread
and a vcpu 0 thread.
--
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2011-02-21 9:29 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2011-02-21 3:13 [Qemu-devel] How can I understand CONFIG_IO_THREAD ? wang sheng
2011-02-21 8:16 ` [Qemu-devel] " Paolo Bonzini
2011-02-21 9:29 ` Avi Kivity
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.