Messages in this thread | | | Date | Thu, 9 Mar 2023 16:39:05 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH 10/10] sched/fair: Implement an EEVDF like policy |
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On Thu, Mar 09, 2023 at 04:29:04PM +0100, Peter Zijlstra wrote: > On Thu, Mar 09, 2023 at 01:44:13PM +0100, Peter Zijlstra wrote: > > On Thu, Mar 09, 2023 at 10:06:33AM +0100, Peter Zijlstra wrote: > > > Hi Mike! > > > > > > On Wed, Mar 08, 2023 at 02:36:01PM +0100, Mike Galbraith wrote: > > > > On Wed, 2023-03-08 at 09:39 +0100, Mike Galbraith wrote: > > > > > > > > > > Curiosity got the best of me... > > > > > > > > Remember this little bugger, allegedly distilled from a real > > > > application control thread starvation issue? > > > > > > Oooh, yeah, I should still have that somewhere. I'll try and remember > > > what exactly was needed to make it behave properly. > > > > That thing wants both wakeup preemption and sleeper bonus. Specifically, > > it needs the signal to insta-preempt the 'pointless' kill loop. > > > > What happens is that while positive lag, we get this, when negative lag > > happens wakeup-preemption is not achieved and we get delayed by a full > > tick. > > > > This gets us very little actual runtime. > > > > Let me see what do do about that... > > So if I add TICK_NSEC based sleeper bonus (/2 for gentle), then starve > works -- this is the absolutely minimal amount required. It sucks a bit > it's HZ dependent, but alas. > > Also, the whole sleeper bonus gets us back into needing to track the old > vruntime and the overflow crap for super long sleeps and all that fugly > :/ I was so hoping we could delete that code. > > Oh well. > > (also, did you know that removing the debug cruft helps with running > numbers? ;-)
Also, it helps to turn the sched_feat on... clearly i should be calling it a day.
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