linux-kernel - Re: [PATCH v5] KVM: halt-polling: poll for the upcoming fire timers

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: Windows password security audit tool. GUI, reports in PDF.

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

Message-ID: <0c7c9b5a-ce15-196b-e83e-627348f04d55@redhat.com>
Date:	Fri, 27 May 2016 11:49:26 +0200
From:	Paolo Bonzini <pbonzini@...hat.com>
To:	yunhong jiang <yunhong.jiang@...ux.intel.com>
Cc:	Wanpeng Li <kernellwp@...il.com>, linux-kernel@...r.kernel.org,
	kvm@...r.kernel.org, Wanpeng Li <wanpeng.li@...mail.com>,
	Radim Krčmář <rkrcmar@...hat.com>,
	David Matlack <dmatlack@...gle.com>,
	Christian Borntraeger <borntraeger@...ibm.com>,
	Yang Zhang <yang.zhang.wz@...il.com>
Subject: Re: [PATCH v5] KVM: halt-polling: poll for the upcoming fire timers



On 26/05/2016 22:33, yunhong jiang wrote:
> On Thu, 26 May 2016 12:26:27 +0200
> Paolo Bonzini <pbonzini@...hat.com> wrote:
> 
>>
>>
>> On 25/05/2016 04:47, Wanpeng Li wrote:
>>> From: Wanpeng Li <wanpeng.li@...mail.com>
>>>
>>> If an emulated lapic timer will fire soon(in the scope of 10us the
>>> base of dynamic halt-polling, lower-end of message passing workload
>>> latency TCP_RR's poll time < 10us) we can treat it as a short halt,
>>> and poll to wait it fire, the fire callback apic_timer_fn() will set
>>> KVM_REQ_PENDING_TIMER, and this flag will be check during busy poll.
>>> This can avoid context switch overhead and the latency which we wake
>>> up vCPU.
>>
>> As discussed on IRC, I would like to understand why the adaptive
> 
> Glad to know the IRC channel. Is #kvm channel on freenode the IRC you are
> talking about?

No, it's #qemu on irc.oftc.net.

Thanks,

Paolo