From: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
To: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: David Hildenbrand <dahi@linux.vnet.ibm.com>,
KVM <kvm@vger.kernel.org>, Paolo Bonzini <pbonzini@redhat.com>,
Gleb Natapov <gleb@kernel.org>,
jfrei@linux.vnet.ibm.com,
Cornelia Huck <cornelia.huck@de.ibm.com>,
Michael Mueller <mimu@linux.vnet.ibm.com>,
raghavendra.kt.linux@gmail.com
Subject: Re: [PATCH RFC 1/2] KVM: don't check for PF_VCPU when yielding
Date: Fri, 28 Nov 2014 17:10:25 +0530 [thread overview]
Message-ID: <54785F29.1060506@linux.vnet.ibm.com> (raw)
In-Reply-To: <54785539.9010005@de.ibm.com>
On 11/28/2014 04:28 PM, Christian Borntraeger wrote:
> Am 28.11.2014 um 11:08 schrieb Raghavendra KT:
>> Was able to test the patch, here is the result: I have not tested with
>> bigger VMs though. Results make it difficult to talk about any side
>> effect of
>> patch if any.
>
> Thanks a log.
>
> If our assumption is correct, then this patch should have no side effect on x86. Do you have any confidence guess if the numbers below mean: no-change vs. regression vs improvement?
>
I am seeing very small improvement in <= 1x commit cases
and for >1x overcommit, a very slight regression. But considering the
test environment noises, I do not see much effect from the
patch.
But I admit, I have not explored deeply about,
1. assumption of preempted approximately equals PF_VCPU case logic,
2. whether it helps for any future usages of yield_to against current
sole usage of virtualization.
next prev parent reply other threads:[~2014-11-28 11:36 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-25 16:04 [PATCH RFC 0/2] assign each vcpu an owning thread and improve yielding David Hildenbrand
2014-11-25 16:04 ` [PATCH RFC 1/2] KVM: don't check for PF_VCPU when yielding David Hildenbrand
2014-11-26 7:51 ` Christian Borntraeger
2014-11-26 9:23 ` David Hildenbrand
2014-11-26 9:31 ` Christian Borntraeger
2014-11-28 10:08 ` Raghavendra KT
2014-11-28 10:58 ` Christian Borntraeger
2014-11-28 11:40 ` Raghavendra K T [this message]
2014-12-01 9:54 ` David Hildenbrand
2014-12-03 12:53 ` Paolo Bonzini
2014-12-03 13:02 ` Paolo Bonzini
2014-12-03 13:04 ` David Hildenbrand
2014-11-25 16:04 ` [PATCH RFC 2/2] KVM: thread creating a vcpu is the owner of that vcpu David Hildenbrand
2014-11-26 7:54 ` Christian Borntraeger
2014-12-03 12:53 ` Paolo Bonzini
2014-12-03 12:12 ` [PATCH RFC 0/2] assign each vcpu an owning thread and improve yielding David Hildenbrand
2014-12-03 12:54 ` Paolo Bonzini
2014-12-03 13:00 ` David Hildenbrand
2014-12-03 13:00 ` Christian Borntraeger
2014-12-03 13:06 ` Paolo Bonzini
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