From: "Li,Rongqing" <lirongqing@baidu.com>
To: Wanpeng Li <kernellwp@gmail.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>, kvm <kvm@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: 答复: [PATCH] KVM: Consider SMT idle status when halt polling
Date: Thu, 22 Jul 2021 12:16:53 +0000 [thread overview]
Message-ID: <4efe4fdb91b747da93d7980c10d016c9@baidu.com> (raw)
In-Reply-To: CANRm+Cx-5Yyxx5A4+qkYa01MG4BCdwXPd++bmxzOid+XL267cQ@mail.gmail.com
> > > 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
>
Run a copy (single thread) Unixbench, with or without a busy poll program in its SMT sibling, and Unixbench score can lower 1/3 with SMT busy polling program
Can this case show this issue?
-Li
> True, it benefits for our real scenario.
>
> this patch can lower our workload compute latency in our multiple cores VM
> which vCPU and pCPU is 1:1 pin, and the workload with lots of computation and
> networking packets.
>
> -Li
next prev parent reply other threads:[~2021-07-22 12:17 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-22 3:58 [PATCH] KVM: Consider SMT idle status when halt polling Li RongQing
2021-07-22 4:15 ` Mika Penttilä
2021-07-22 5:22 ` 答复: " Li,Rongqing
2021-07-22 5:55 ` Wanpeng Li
2021-07-22 7:10 ` 答复: " Li,Rongqing
2021-07-22 12:16 ` Li,Rongqing [this message]
2021-07-27 1:25 ` Sean Christopherson
2021-07-27 6:39 ` 答复: " Li,Rongqing
2021-07-22 13:35 ` kernel test robot
2021-07-22 14:52 ` kernel test robot
2021-07-22 15:07 ` Dongli Zhang
2021-07-22 15:20 ` Dongli Zhang
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