Re: [Xen-devel] [RFC PATCH v2] Implement Batched (group) ticket lock

[Peter Zijlstra <peterz@xxxxxxxxxxxxx>]

On Tue, Jul 01, 2014 at 03:14:09PM +0530, Raghavendra K T wrote:
> On 07/01/2014 01:35 PM, Peter Zijlstra wrote:
> >On Sat, Jun 28, 2014 at 02:47:04PM +0530, Raghavendra K T wrote:
> >>In virtualized environment there are mainly three problems
> >>related to spinlocks that affects performance.
> >>1. LHP (lock holder preemption)
> >>2. Lock Waiter Preemption (LWP)
> >>3. Starvation/fairness
> >>
> >>Though Ticketlocks solve fairness problem it worsens LWP, LHP problems. 
> >>Though
> >>pv-ticketlocks tried to address these problems we can further improve at the
> >>  cost of relaxed fairness. The following patch tries to achieve that by 
> >> grouping
> >>(batched) ticketlocks.
> >
> >And here I stop reading and ignore this patch, right?
> >
> >Why should I look at this?
> >
> 
> For baremetal we continue to have 'fully fair ticketlock' with this patch
> series.
> 

But but but, we're looking at removing ticket locks. So why do we want
to invest in them now?

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