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xen-devel
Re: [Xen-devel] [PATCH 00/10] [PATCH RFC V2] Paravirtualized	ticketlocks
 
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To:  | 
Jeremy Fitzhardinge <jeremy@xxxxxxxx> | 
 
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Subject:  | 
Re: [Xen-devel] [PATCH 00/10] [PATCH RFC V2] Paravirtualized	ticketlocks | 
 
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From:  | 
Ingo Molnar <mingo@xxxxxxx> | 
 
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Date:  | 
Mon, 10 Oct 2011 09:32:14 +0200 | 
 
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Cc:  | 
Jeremy Fitzhardinge <jeremy.fitzhardinge@xxxxxxxxxx>,	Nick Piggin <npiggin@xxxxxxxxx>, KVM <kvm@xxxxxxxxxxxxxxx>,	Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>,	Peter Zijlstra <peterz@xxxxxxxxxxxxx>,	the arch/x86 maintainers <x86@xxxxxxxxxx>,	Linux Kernel Mailing List <linux-kernel@xxxxxxxxxxxxxxx>,	Marcelo Tosatti <mtosatti@xxxxxxxxxx>,	Andi Kleen <andi@xxxxxxxxxxxxxx>, Avi Kivity <avi@xxxxxxxxxx>,	Jan Beulich <JBeulich@xxxxxxxx>, "H. Peter Anvin" <hpa@xxxxxxxxx>,	Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>,	"xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>,	Stephan Diestelhorst <stephan.diestelhorst@xxxxxxx> | 
 
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Mon, 10 Oct 2011 00:35:29 -0700 | 
 
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* Jeremy Fitzhardinge <jeremy@xxxxxxxx> wrote:
> On 10/06/2011 10:40 AM, Jeremy Fitzhardinge wrote:
> > However, it looks like locked xadd is also has better performance:  on
> > my Sandybridge laptop (2 cores, 4 threads), the add+mfence is 20% slower
> > than locked xadd, so that pretty much settles it unless you think
> > there'd be a dramatic difference on an AMD system.
> 
> Konrad measures add+mfence is about 65% slower on AMD Phenom as well.
xadd also results in smaller/tighter code, right?
Thanks,
        Ingo
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