From: Christian Borntraeger <borntraeger@de.ibm.com>
To: Paolo Bonzini <pbonzini@redhat.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: Thu, 24 Sep 2015 13:06:16 +0200 [thread overview]
Message-ID: <5603D928.7000606@de.ibm.com> (raw)
In-Reply-To: <55FBF5B2.6090907@redhat.com>
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?
Christian
next prev parent reply other threads:[~2015-09-24 11:06 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 [this message]
2015-09-25 7:50 ` Paolo Bonzini
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=5603D928.7000606@de.ibm.com \
--to=borntraeger@de.ibm.com \
--cc=dahi@linux.vnet.ibm.com \
--cc=dmatlack@google.com \
--cc=kvm@vger.kernel.org \
--cc=pbonzini@redhat.com \
--cc=rkrcmar@redhat.com \
--cc=wanpeng.li@hotmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).