From: Paolo Bonzini <pbonzini@redhat.com>
To: "Sean Christopherson" <sean.j.christopherson@intel.com>,
"Radim Krčmář" <rkrcmar@redhat.com>
Cc: kvm@vger.kernel.org, Wanpeng Li <kernellwp@gmail.com>
Subject: Re: [PATCH] KVM: lapic: Reuse auto-adjusted timer advance of first stable vCPU
Date: Mon, 20 May 2019 15:03:10 +0200 [thread overview]
Message-ID: <3ea5ae51-89b2-ee0c-d156-88198af90b95@redhat.com> (raw)
In-Reply-To: <20190508214702.25317-1-sean.j.christopherson@intel.com>
On 08/05/19 23:47, Sean Christopherson wrote:
> +
> + /*
> + * The first vCPU to get a stable advancement time "wins" and
> + * sets the advancement time that is used for *new* vCPUS that
> + * are created with auto-adjusting enabled.
> + */
> + if (apic->lapic_timer.timer_advance_adjust_done)
> + (void)cmpxchg(&adjusted_timer_advance_ns, -1,
> + timer_advance_ns);
This is relatively expensive, so it should only be done after setting
timer_advance_adjust_done to true.
Paolo
next prev parent reply other threads:[~2019-05-20 13:03 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-08 21:47 [PATCH] KVM: lapic: Reuse auto-adjusted timer advance of first stable vCPU Sean Christopherson
2019-05-20 13:03 ` Paolo Bonzini [this message]
2019-05-24 20:23 ` Sean Christopherson
2019-05-24 20:48 ` Paolo Bonzini
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