linux-kernel - Re: [PATCH] KVM: Consider SMT idle status when halt polling

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Message-ID: <CANRm+Cx-5Yyxx5A4+qkYa01MG4BCdwXPd++bmxzOid+XL267cQ@mail.gmail.com>
Date:   Thu, 22 Jul 2021 13:55:06 +0800
From:   Wanpeng Li <kernellwp@...il.com>
To:     Li RongQing <lirongqing@...du.com>
Cc:     Paolo Bonzini <pbonzini@...hat.com>,
        Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        kvm <kvm@...r.kernel.org>, LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] KVM: Consider SMT idle status when halt polling

On Thu, 22 Jul 2021 at 12:07, Li RongQing <lirongqing@...du.com> wrote:
>
> SMT siblings share caches and other hardware, halt polling
> will degrade its sibling performance if its sibling is busy

Do you have any real scenario benefits? As the polling nature, some
cloud providers will configure to their preferred balance of cpu usage
and performance, and other cloud providers for their NFV scenarios
which are more sensitive to latency are vCPU and pCPU 1:1 pin，you
destroy these setups.

    Wanpeng