Re: [PATCH -tip 0/2] kernel/smp: Small csd_lock optimizations

From: Peter Zijlstra
Date: Thu Mar 10 2016 - 04:17:32 EST


On Wed, Mar 09, 2016 at 05:55:34PM -0800, Davidlohr Bueso wrote:
> From: Davidlohr Bueso <dave@xxxxxxxxxxxx>
>
> Hi,
>
> Justifications are in each patch, there is slight impact (patch 2)
> on some tlb flushing intensive benchmarks (albeit using ipi batching
> nowadays). Specifically for the pft
> benchmark, on a 12-core box:

> 4.4 4.4
> vanilla smp
> User 11.91 11.85
> System 197.11 194.69
> Elapsed 44.24 40.26
>
> While the single thread is an abnormality, overall we don't seem
> to do any harm (noise range). Could be give or take, but overall
> the patches at least make some sense afaict.

Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>