Re: [POC][RFC][PATCH v2] sched: Extended Scheduler Time Slice

[Peter Zijlstra <peterz@xxxxxxxxxxxxx>]

On Wed, Oct 25, 2023 at 11:54:13PM -0400, Steven Rostedt wrote:

>  static void extend(void)
>  {
> 	rseq_map.cr_flags = 1;
>  }
> 
>  static void unextend(void)
>  {
> 	unsigned long prev;
> 
> 	prev = xchg(&rseq_map.cr_flags, 0);

So you complain about overhead and then you add one of the most
expensive ops possible here? xchg has an implicit LOCK prefix and you
really don't need LOCK prefix here.

> 	if (prev & 2) {
> 		tracefs_printf(NULL, "Yield!\n");
> 		sched_yield();
> 	}
>  }