Message-ID: <4FA7E226.5060809@redhat.com>
Date: Mon, 07 May 2012 17:54:30 +0300
From: Avi Kivity <avi@redhat.com>
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To: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
CC: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>,
        Ingo Molnar <mingo@kernel.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Jeremy Fitzhardinge <jeremy@goop.org>,
        Greg Kroah-Hartman <gregkh@suse.de>,
        Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
        "H. Peter Anvin" <hpa@zytor.com>,
        Marcelo Tosatti <mtosatti@redhat.com>, X86 <x86@kernel.org>,
        Gleb Natapov <gleb@redhat.com>, Ingo Molnar <mingo@redhat.com>,
        Attilio Rao <attilio.rao@citrix.com>,
        Virtualization <virtualization@lists.linux-foundation.org>,
        Xen Devel <xen-devel@lists.xensource.com>, linux-doc@vger.kernel.org,
        KVM <kvm@vger.kernel.org>, Andi Kleen <andi@firstfloor.org>,
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        Stephan Diestelhorst <stephan.diestelhorst@amd.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>,
        Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH RFC V8 0/17] Paravirtualized ticket spinlocks
References: <20120502100610.13206.40.sendpatchset@codeblue.in.ibm.com> <20120507082928.GI16608@gmail.com> <4FA7888F.80505@redhat.com> <4FA7AAD8.6050003@linux.vnet.ibm.com> <4FA7BABA.4040700@redhat.com> <4FA7CC05.50808@linux.vnet.ibm.com> <4FA7CCA2.4030408@redhat.com> <4FA7D06B.60005@linux.vnet.ibm.com> <20120507134611.GB5533@linux.vnet.ibm.com> <4FA7D2E5.1020607@redhat.com> <4FA7D3F7.9080005@linux.vnet.ibm.com> <4FA7D50D.1020209@redhat.com> <4FA7E06E.20304@linux.vnet.ibm.com> <4FA7E1C8.7010509@redhat.com>
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On 05/07/2012 05:52 PM, Avi Kivity wrote:
> > Having said that, it is hard for me to resist saying :
> >  bottleneck is somewhere else on PLE m/c and IMHO answer would be
> > combination of paravirt-spinlock + pv-flush-tb.
> >
> > But I need to come up with good number to argue in favour of the claim.
> >
> > PS: Nikunj had experimented that pv-flush tlb + paravirt-spinlock is a
> > win on PLE where only one of them alone could not prove the benefit.
> >
>
> I'd like to see those numbers, then.
>

Note: it's probably best to try very wide guests, where the overhead of
iterating on all vcpus begins to show.

-- 
error compiling committee.c: too many arguments to function

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