linux-kernel - Re: [PATCH 0/2] KVM: enable halt poll shrink parameter

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Message-ID: <171754275211.2777812.9934084019005836188.b4-ty@google.com>
Date: Tue,  4 Jun 2024 16:29:29 -0700
From: Sean Christopherson <seanjc@...gle.com>
To: Sean Christopherson <seanjc@...gle.com>, kvm@...r.kernel.org, pbonzini@...hat.com, 
	Parshuram Sangle <parshuram.sangle@...el.com>
Cc: linux-kernel@...r.kernel.org, jaishankar.rajendran@...el.com
Subject: Re: [PATCH 0/2] KVM: enable halt poll shrink parameter

On Thu, 02 Nov 2023 21:16:26 +0530, Parshuram Sangle wrote:
> KVM halt polling interval growth and shrink behavior has evolved since its
> inception. The current mechanism adjusts the polling interval based on whether
> vcpu wakeup was received or not during polling interval using grow and shrink
> parameter values. Though grow parameter is logically set to 2 by default,
> shrink parameter is kept disabled (set to 0).
> 
> Disabled shrink has two issues:
> 1) Resets polling interval to 0 on every un-successful poll assuming it is
> less likely to receive a vcpu wakeup in further shrunk intervals.
> 2) Even on successful poll, if total block time is greater or equal to current
> poll_ns value, polling interval is reset to 0 instead shrinking gradually.
> 
> [...]

Applied to kvm-x86 generic, with a reduced version of the doc update as
described in response to patch 2.  Thanks!

[1/2] KVM: enable halt polling shrink parameter by default
      https://github.com/kvm-x86/linux/commit/aeb1b22a3ac8
[2/2] KVM: documentation update to halt polling
      https://github.com/kvm-x86/linux/commit/f8aadead1971

--
https://github.com/kvm-x86/linux/tree/next