Re: [PATCH v3 0/2] fs/pipe: reduce pipe->mutex contention by pre-allocating outside the lock

[Breno Leitao]

On Wed, Jun 17, 2026 at 05:01:04PM +0200, Mateusz Guzik wrote:
> On Wed, Jun 17, 2026 at 03:23:54AM -0700, Breno Leitao wrote:
> > Measured it to _just be sure_, 1-byte ping-pong (perf bench sched pipe -s 1):
> > 
> >     baseline:  2.674 usecs/op
> >     patched:   2.710 usecs/op   (+1.3%, within run-to-run noise)
> > 
> 
> Can you try this:

I've tested this change, but the results show no real measurable
improvement beyond measurement noise.

	patched + your change: ~2.66 usecs/op   (-1.7%, within noise)

In my experience, branch hints haven't proven particularly effective, at
least that was the case when I worked on PowerPC some time ago.