From: Marcelo Tosatti <mtosatti@redhat.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
riel@redhat.com, rkrcmar@redhat.com, dmatlack@google.com
Subject: Re: [PATCH 2/2] KVM: x86: optimize delivery of TSC deadline timer interrupt
Date: Tue, 10 Feb 2015 17:30:18 -0200 [thread overview]
Message-ID: <20150210193018.GA32006@amt.cnet> (raw)
In-Reply-To: <54D67685.5050205@redhat.com>
On Sat, Feb 07, 2015 at 09:33:09PM +0100, Paolo Bonzini wrote:
> > Can remove another 300 cycles from do_div when programming LAPIC
> > tscdeadline timer.
>
> Do you mean using something like lib/reciprocal_div.c?
Yes.
> Good idea,
> though that's not latency, it's just being slow. :)
It adds to latency, yes (the guest will reprogram the
APIC timer before resuming userspace execution).
prev parent reply other threads:[~2015-02-10 19:30 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-06 12:16 [PATCH 0/2] KVM: APIC timer latency improvement Paolo Bonzini
2015-02-06 12:16 ` [PATCH 1/2] KVM: x86: extract guest running logic from __vcpu_run Paolo Bonzini
2015-02-09 22:44 ` David Matlack
2015-02-10 8:18 ` Paolo Bonzini
2015-02-09 23:32 ` Rik van Riel
2015-02-06 12:16 ` [PATCH 2/2] KVM: x86: optimize delivery of TSC deadline timer interrupt Paolo Bonzini
2015-02-06 20:51 ` Marcelo Tosatti
2015-02-07 20:33 ` Paolo Bonzini
2015-02-10 19:30 ` Marcelo Tosatti [this message]
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