Re: Preemptable Ticket Spinlock

[Raghavendra K T]

On 04/23/2013 02:31 AM, Peter Zijlstra wrote:
> On Mon, 2013-04-22 at 16:49 -0400, Rik van Riel wrote:
> > Given the fairly high cost of rescheduling a VCPU (which is likely
> > to include an IPI), versus the short hold time of most spinlocks,
> > I have the strong suspicion that your approach would win.
>
>    https://lkml.org/lkml/2012/5/2/101
>
> If you schedule too often your SPIN_THRESHOLD is far too low.
>
> Anyway.. performance can't be that bad, otherwise Jeremey would have
> spend as much time on it as he did.

When I experimented last time ideal SPIN_THRESHOLD for PLE machine,
was around 4k, 8k. Jeremy's experiment was on a non-PLE machine AFAIK,
which complemented PLE feature in a nice way with 2k threshold.

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