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From: Paolo Bonzini <pbonzini@redhat.com>
To: mad Engineer <themadengin33r@gmail.com>
Cc: kvm@vger.kernel.org
Subject: Re: Number of threads for virtual machine process
Date: Tue, 17 Feb 2015 07:51:56 +0100	[thread overview]
Message-ID: <54E2E50C.5010409@redhat.com> (raw)
In-Reply-To: <CAN8oO4Cs923FpXFh2M6fv5_4i5vvhCgmD41rhVz-5a17nKGwbw@mail.gmail.com>



On 17/02/2015 05:44, mad Engineer wrote:
> Thanks for the response.
>            Can a vm process create any number of extra threads based
> on i/o requirement ,or is there any relation between number of VCPU
> allowed and these extra threads.

No, there is not relation.  The I/O threads are created by QEMU, which
is a userspace program that uses KVM.  Different implementations could
do I/O in a different way.  Alternatively, QEMU itself can use the Linux
AIO API.  In that case it still creates threads to do fdatasync, but not
to do read/write.

> I hope these threads are for disk i/o and for network it uses
> vhost-'pid' process.

For network it can use vhost or do everything into the main thread of QEMU.

Paolo

      reply	other threads:[~2015-02-17  6:52 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-02-16 10:54 Number of threads for virtual machine process mad Engineer
2015-02-16 15:51 ` Paolo Bonzini
2015-02-17  4:44   ` mad Engineer
2015-02-17  6:51     ` Paolo Bonzini [this message]

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