On Thu, Jun 11, 2026 at 07:17:41AM +0000, Dmitry Ilvokhin wrote:
> On Wed, Jun 03, 2026 at 02:08:11PM +0200, Peter Zijlstra wrote:
> > Also, I think someone should go do some performance runs with
> > ARCH_INLINE_SPIN_* set for x86 just like for s390.
>
> As promised, I set ARCH_INLINE_SPIN_UNLOCK{,_BH,_IRQ,_IRQRESTORE} for
> x86 and measured the effect on a few real workloads.
>
> Short version: inlining of _raw_spin_unlock() adds measurable kernel
> i-cache pressure on every workload I tried, and on a
> kernel-i-cache-bound one (nginx connection churn) it costs ~1.27%
> throughput. I did not find a workload where it helps.
Thanks for checking!
