linux-kernel - Re: [RFC PATCH v3 0/6] KVM: x86: avoid redundant REQ

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Date:   Tue, 20 Dec 2016 13:01:55 +0300
From:   Roman Kagan <rkagan@...tuozzo.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
CC:     Denis Plotnikov <dplotnikov@...tuozzo.com>,
        <linux-kernel@...r.kernel.org>, <kvm@...r.kernel.org>,
        <rkrcmar@...hat.com>
Subject: Re: [RFC PATCH v3 0/6] KVM: x86: avoid redundant REQ_EVENT

On Mon, Dec 19, 2016 at 03:30:17PM +0100, Paolo Bonzini wrote:
> 
> 
> On 19/12/2016 14:05, Denis Plotnikov wrote:
> >>
> > This new patch-set does avoid unnecessary interrupt re-injections -
> > checked.
> > 
> > The test (MS Windows, sending messages between multiple windows using
> > windows-specific interface),
> > which showed performance growth with "[PATCH v2] KVM: x86: avoid
> > redundant REQ_EVENT" showed pretty much the same performance level with
> > this new patch-set.
> > The test score difference (+2.4% to [PATCH v2]) is within the tolerance
> > range(5%).
> > 
> > The test score on mainstream v4.9 kernel CPU Intel i5-2400, guest
> > Windows Server 2012 2VCPU, 2GB:
> > 
> > without patch: 31510 (+/- 4%)
> >    with patch: 36270 (+/- 5%)
> > 
> > difference = (36270-31510)/31510 * 100 = +15% -- looks good!
> 
> Awesome!  I hope it also qualifies as less ugly. :)

Absolutely.  FWIW

Reviewed-by: Roman Kagan <rkagan@...tuozzo.com>

Roman.