Messages in this thread | | | Date | Fri, 17 Dec 2021 20:48:47 +0100 | From | Sebastian Andrzej Siewior <> | Subject | Re: [PATCH-next v3] mm/memcg: Properly handle memcg_stock access for PREEMPT_RT |
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On 2021-12-17 13:46:53 [-0500], Waiman Long wrote: > > annotation. Looking at the history, I'm also impressed by that fact that > > disabling/ enabling interrupts is *so* expensive that all this is > > actually worth it. > > For !RT with voluntary or no preemption, preempt_disable() is just a > compiler barrier. So it is definitely cheaper than disabling interrupt. The > performance benefit is less with preemptible but !RT kernel. Microbenchmark > testing shows a performance improvement of a few percents depending on the > exact benchmark.
Thanks for confirming. I got the feeling that this optimisation is for !CONFIG_PREEMPTION. So I instead of depending on CONFIG_PREEMPT_RT I'm leaning towards CONFIG_PREEMPT instead.
> Cheers, > Longman
Sebastian
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