From: Wanpeng Li <kernellwp@gmail.com>
To: Kenta Ishiguro <kentaishiguro@sslab.ics.keio.ac.jp>
Cc: "David Hildenbrand" <david@redhat.com>,
"Jim Mattson" <jmattson@google.com>,
"Joerg Roedel" <joro@8bytes.org>,
河野健二 <kono@sslab.ics.keio.ac.jp>, kvm <kvm@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Pierre-Louis Aublin" <pl@sslab.ics.keio.ac.jp>,
"Sean Christopherson" <seanjc@google.com>,
"Vitaly Kuznetsov" <vkuznets@redhat.com>,
"Wanpeng Li" <wanpengli@tencent.com>
Subject: Re: [RFC PATCH 0/2] Mitigating Excessive Pause-Loop Exiting in VM-Agnostic KVM
Date: Mon, 26 Apr 2021 11:58:19 +0800 [thread overview]
Message-ID: <CANRm+Cz9GgQFDbbW_3bRO35FwvMGJ-ZFa0rSvEimxFzrvwmpJw@mail.gmail.com> (raw)
In-Reply-To: <20210426031858.12003-1-kentaishiguro@sslab.ics.keio.ac.jp>
On Mon, 26 Apr 2021 at 11:19, Kenta Ishiguro
<kentaishiguro@sslab.ics.keio.ac.jp> wrote:
>
> Thank you for the reply.
>
> My question is about following scenario:
> 1. running vCPU receives IPI and the vCPU's ipi_received gets true
> 2. the vCPU responds to the IPI
> 3. the vCPU exits
> 4. the vCPU is preempted by KVM
> 5. the vCPU is boosted, but it has already responded to the IPI
> 6. the vCPU enters and the vCPU's ipi_received is cleaned
>
> In this case, I think the check of vcpu->preempted does not limit the candidate vCPUs.
Good point, you are right. However, actually I played with that code a
bit before, I have another version adding the vcpu->preempted checking
when marking IPI receiver, the score is not as good as expected.
Wanpeng
next prev parent reply other threads:[~2021-04-26 3:58 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-21 15:08 [RFC PATCH 0/2] Mitigating Excessive Pause-Loop Exiting in VM-Agnostic KVM Kenta Ishiguro
2021-04-21 15:08 ` [RFC PATCH 1/2] Prevent CFS from ignoring boost requests from KVM Kenta Ishiguro
2021-04-21 18:42 ` kernel test robot
2021-04-21 15:08 ` [RFC PATCH 2/2] Boost vCPUs based on IPI-sender and receiver information Kenta Ishiguro
2021-04-21 15:43 ` Sean Christopherson
2021-04-21 16:16 ` Sean Christopherson
2021-04-21 16:19 ` [RFC PATCH 0/2] Mitigating Excessive Pause-Loop Exiting in VM-Agnostic KVM Sean Christopherson
2021-04-22 12:21 ` Wanpeng Li
2021-04-22 15:58 ` Sean Christopherson
[not found] ` <CAOOWTGJvFB_hgSUzaqNaNigdkRXFcaK37F9V7kmL3nCG+bFz5Q@mail.gmail.com>
2021-04-26 3:02 ` Wanpeng Li
2021-04-26 3:18 ` Kenta Ishiguro
2021-04-26 3:58 ` Wanpeng Li [this message]
2021-04-26 4:10 ` Kenta Ishiguro
2021-04-22 0:55 ` Wanpeng Li
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