On Thu, 28 Sep 2017 14:29:02 +0200 Laurent Dufour [off-list ref] wrote:

quoted

Laurent's [0/n] provides some nice-looking performance benefits for
workloads which are chosen to show performance benefits(!) but, alas,
no quantitative testing results for workloads which we may suspect will
be harmed by the changes(?).  Even things as simple as impact upon
single-threaded pagefault-intensive workloads and its effect upon
CONFIG_SMP=n .text size?

I forgot to mention in my previous email the impact on the .text section.

Here are the metrics I got :

.text size	UP		SMP		Delta
4.13-mmotm	8444201		8964137		6.16%
'' +spf		8452041		8971929		6.15%
	Delta	0.09%		0.09%	

No major impact as you could see.

8k text increase seems rather a lot actually.  That's a lot more
userspace cacheclines that get evicted during a fault...

Is the feature actually beneficial on uniprocessor?