From: Sean Christopherson <seanjc@google.com>
To: 76824143@qq.com
Cc: pbonzini@redhat.com, kvm@vger.kernel.org,
zhanghao <zhanghao1@kylinos.cn>
Subject: Re: [PATCH 3/3] KVM: x86: Use dynamic try count based on vCPU count
Date: Tue, 17 Feb 2026 08:21:02 -0800 [thread overview]
Message-ID: <aZSVbjPhURBe1Rj0@google.com> (raw)
In-Reply-To: <tencent_EAB2053E04BF4C7F996CEC61331C23154007@qq.com>
On Sun, Feb 15, 2026, 76824143@qq.com wrote:
> From: zhanghao <zhanghao1@kylinos.cn>
>
> Replace the fixed try count (3) with a dynamic calculation based
> on the number of online vCPUs. This allows larger VMs to try more
> candidates before giving up, while keeping small VMs efficient.
>
> Formula: clamp(ilog2(nr_vcpus + 1), 3, 10)
> - 4 vCPUs: try = 3
> - 64 vCPUs: try = 6
> - 256 vCPUs: try = 8
Why do larger VMs warrant more attempts though? E.g. what are practical downsides
of trying min(nr_vcpus - 1, 8) times?
next prev parent reply other threads:[~2026-02-17 16:21 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20260215140402.24659-1-76824143@qq.com>
2026-02-15 14:04 ` [PATCH 1/3] KVM: x86: Enhance kvm_vcpu_eligible_for_directed_yield to detect golden targets 76824143
2026-02-17 15:37 ` Sean Christopherson
2026-02-15 14:04 ` [PATCH 2/3] KVM: x86: Skip IN_GUEST_MODE vCPUs in kvm_vcpu_on_spin main loop 76824143
2026-02-17 15:41 ` Sean Christopherson
2026-03-12 5:57 ` zhanghao
2026-03-13 1:02 ` Sean Christopherson
2026-03-19 8:40 ` zhanghao
2026-02-15 14:04 ` [PATCH 3/3] KVM: x86: Use dynamic try count based on vCPU count 76824143
2026-02-17 16:21 ` Sean Christopherson [this message]
2026-03-12 6:24 ` zhanghao
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