linux-kernel - Re: [PATCH v3] KVM: halt-polling: poll if emulated lapic timer will fire soon

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Message-ID: <CANRm+Cz+4uW45KYrsh0BJMBhZA84wRqwLYw93Fp7MBEAg99HtA@mail.gmail.com>
Date:	Thu, 26 May 2016 16:04:10 +0800
From:	Wanpeng Li <kernellwp@...il.com>
To:	David Matlack <dmatlack@...gle.com>
Cc:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	kvm list <kvm@...r.kernel.org>,
	Wanpeng Li <wanpeng.li@...mail.com>,
	Paolo Bonzini <pbonzini@...hat.com>,
	Radim Krčmář <rkrcmar@...hat.com>,
	Christian Borntraeger <borntraeger@...ibm.com>,
	Yang Zhang <yang.zhang.wz@...il.com>,
	Yunhong Jiang <yunhong.jiang@...el.com>
Subject: Re: [PATCH v3] KVM: halt-polling: poll if emulated lapic timer will
 fire soon

2016-05-24 2:01 GMT+08:00 David Matlack <dmatlack@...gle.com>:
> On Sun, May 22, 2016 at 5:42 PM, Wanpeng Li <kernellwp@...il.com> wrote:
>> From: Wanpeng Li <wanpeng.li@...mail.com>
>
> I'm ok with this patch, but I'd like to better understand the target
> workloads. What type of workloads do you expect to benefit from this?
>

In addition, as Paolo great pointed out
http://www.spinics.net/lists/kvm/msg132983.html, the upcoming vmx
preemption timer also can get benefit, preemption time will just
switch to hrtimer if block, if the remaining expire time is enough
small and there is just a single task in this pCPU, poll will cut the
latency.

Regards,
Wanpeng Li