From: Paolo Bonzini <pbonzini@redhat.com>
To: Christian Borntraeger <borntraeger@de.ibm.com>,
David Hildenbrand <dahi@linux.vnet.ibm.com>,
kvm@vger.kernel.org
Cc: wanpeng.li@hotmail.com, dmatlack@google.com, rkrcmar@redhat.com
Subject: Re: [PATCH] KVM: disable halt_poll_ns as default for s390x
Date: Fri, 25 Sep 2015 09:50:37 +0200 [thread overview]
Message-ID: <5604FCCD.2090100@redhat.com> (raw)
In-Reply-To: <5603D928.7000606@de.ibm.com>
On 24/09/2015 13:06, Christian Borntraeger wrote:
> Am 18.09.2015 um 13:29 schrieb Paolo Bonzini:
>>
>>
>> On 18/09/2015 12:54, Christian Borntraeger wrote:
>>>> -/* halt polling only reduces halt latency by 5-7 us, 500us is enough */
>>>> -static unsigned int halt_poll_ns = 500000;
>>>> +/* Architectures should define their poll value according to the halt latency */
>>>> +static unsigned int halt_poll_ns = KVM_HALT_POLL_NS_DEFAULT;
>>>
>>> Yes, I prefer this over disabling it via Kconfig. There are benchmarks which
>>> benefit from polling on s390. Furthermore it seems that the latency
>>> strongly depends on timing of the architecture so making it per arch is
>>> probably the right thing to do.
>>
>> Perhaps a #ifndef is better than replicating the 500us default in all
>> architectures? Or should the default be 0?
>
> Any guidance from your side? All different proposals are certainly ok.
> Are you going to take Davids patch or shall he respin?
I've committed the patch as is, and I'm preparing a pull request.
Paolo
prev parent reply other threads:[~2015-09-25 7:50 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-18 10:34 [PATCH] KVM: disable halt_poll_ns as default for s390x David Hildenbrand
2015-09-18 10:54 ` Christian Borntraeger
2015-09-18 11:29 ` Paolo Bonzini
2015-09-18 11:35 ` Christian Borntraeger
2015-09-24 11:06 ` Christian Borntraeger
2015-09-25 7:50 ` Paolo Bonzini [this message]
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