linux-kernel - Re: [PATCH v2 2/3] KVM: dynamic halt_poll

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Wed, 26 Aug 2015 17:12:48 +0800
From:	Wanpeng Li <wanpeng.li@...mail.com>
To:	David Matlack <dmatlack@...gle.com>
CC:	Paolo Bonzini <pbonzini@...hat.com>,
	kvm list <kvm@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 2/3] KVM: dynamic halt_poll_ns adjustment

On 8/26/15 1:19 AM, David Matlack wrote:
> Thanks for writing v2, Wanpeng.
>
> On Mon, Aug 24, 2015 at 11:35 PM, Wanpeng Li <wanpeng.li@...mail.com> wrote:
>> There is a downside of halt_poll_ns since poll is still happen for idle
>> VCPU which can waste cpu usage. This patch adds the ability to adjust
>> halt_poll_ns dynamically.
> What testing have you done with these patches? Do you know if this removes
> the overhead of polling in idle VCPUs? Do we lose any of the performance
> from always polling?

There is 0.8% kernel compile performance improvement(10 iterations) on 
host w/ 800 idle vCPUs. Btw, I handle all your comments in v3. Many 
thanks for your review, David! :-)

Regards,
Wanpeng Li
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/