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From: Avi Kivity <avi@redhat.com>
To: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: vatsa@linux.vnet.ibm.com, Marcelo Tosatti <mtosatti@redhat.com>,
	Gleb Natapov <gleb@redhat.com>,
	linux-kernel@vger.kernel.org, npiggin@suse.de,
	kvm@vger.kernel.org, bharata@in.ibm.com,
	Balbir Singh <balbir@in.ibm.com>,
	Jan Beulich <JBeulich@novell.com>
Subject: Re: [PATCH RFC 2/4] Add yield hypercall for KVM guests
Date: Mon, 02 Aug 2010 11:32:35 +0300	[thread overview]
Message-ID: <4C5682A3.40409@redhat.com> (raw)
In-Reply-To: <4C4DC3AD.7010404@goop.org>

  On 07/26/2010 08:19 PM, Jeremy Fitzhardinge wrote:
>  On 07/25/2010 11:14 PM, Srivatsa Vaddagiri wrote:
>> Add KVM hypercall for yielding vcpu timeslice.
>
> Can you do a directed yield?
>

A problem with directed yield is figuring out who to yield to.  One idea 
is to look for a random vcpu that is not running and donate some runtime 
to it.  In the best case, it's the lock holder and we cause it to start 
running.  Middle case it's not the lock holder, but we lose enough 
runtime to stop running, so at least we don't waste cpu.  Worst case we 
continue running not having woken the lock holder.  Spin again, yield 
again hoping to find the right vcpu.

-- 
error compiling committee.c: too many arguments to function


  parent reply	other threads:[~2010-08-02  8:32 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-07-26  6:11 [PATCH RFC 0/4] Paravirt-spinlock implementation for KVM guests (Version 0) Srivatsa Vaddagiri
2010-07-26  6:13 ` [PATCH RFC 1/4] Debugfs support for reading an array of u32-type integers Srivatsa Vaddagiri
2010-07-26  6:14 ` [PATCH RFC 2/4] Add yield hypercall for KVM guests Srivatsa Vaddagiri
2010-07-26 17:19   ` Jeremy Fitzhardinge
2010-07-28 14:55     ` Srivatsa Vaddagiri
2010-08-02  8:40       ` Avi Kivity
2010-08-03  5:16         ` Srivatsa Vaddagiri
2010-08-03  5:33           ` Srivatsa Vaddagiri
2010-08-02  8:32     ` Avi Kivity [this message]
2010-08-02 14:42       ` Ryan Harper
2010-08-02 14:50         ` Avi Kivity
2010-08-02 15:08       ` Jeremy Fitzhardinge
2010-07-26  6:15 ` [PATCH RFC 3/4] Paravirtualized spinlock implementation " Srivatsa Vaddagiri
2010-08-02  8:48   ` Avi Kivity
2010-08-02 15:20     ` Jeremy Fitzhardinge
2010-08-03  6:59       ` Avi Kivity
2010-08-03 17:47         ` Jeremy Fitzhardinge
2010-08-02  8:53   ` Avi Kivity
2010-07-26  6:16 ` [PATCH RFC 4/4] Add yield hypercall support in Qemu Srivatsa Vaddagiri
2010-07-26 17:18 ` [PATCH RFC 0/4] Paravirt-spinlock implementation for KVM guests (Version 0) Jeremy Fitzhardinge
2010-07-28 14:47   ` Srivatsa Vaddagiri
2010-07-28 22:10 ` Konrad Rzeszutek Wilk
2010-07-28 22:42   ` Konrad Rzeszutek Wilk
2010-08-02  8:50 ` Avi Kivity

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