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
