From: Anthony Liguori <anthony@codemonkey.ws>
To: alex <tomorrowanewday@gmail.com>
Cc: avi@redhat.com, kvm@vger.kernel.org
Subject: Re: Is guest OS oriented scheduling welcome?
Date: Fri, 24 Apr 2009 08:16:54 -0500 [thread overview]
Message-ID: <49F1BBC6.4010906@codemonkey.ws> (raw)
In-Reply-To: <820ac2e90904232310g48a978f0wb482deae064aed97@mail.gmail.com>
alex wrote:
> just now, I tried cgroup. I admit that as far as only CPU share is
> concerned, cgroup is enough.
>
> However, AFAIK Linux schedules each thread independently, ignoring the
> upper level logic.
>
> for example, suppose VM1 is an SMP one, and it is used to receive
> network packets, which causes it run the TCP/IP stack code frequently.
> The use of spin-lock implies that the lock holder will release it
> fast. However, when vcpu threads are scheduled independently, when one
> vcpu is spinning, the lock holder might be off the CPU! This would
> make the VM's SMP scalability bad.
>
Sure, but credit doesn't do gang scheduling either.
Instead of gang scheduling, I think the best solution to this problem is
spin lock paravirtualization.
Regards,
Anthony Liguori
next prev parent reply other threads:[~2009-04-24 13:16 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-24 6:10 Re:Re: Is guest OS oriented scheduling welcome? alex
2009-04-24 13:16 ` Anthony Liguori [this message]
[not found] <1060494.867561240402736300.JavaMail.coremail@app167.163.com>
2009-04-22 12:22 ` Avi Kivity
2009-04-22 12:34 ` Daniel P. Berrange
2009-04-24 0:19 ` Anthony Liguori
2009-04-24 2:55 ` Andrew de Andrade
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