Re: [RFC PATCH 1/1] sched: Extend cpu idle state for 1ms

[Mathieu Desnoyers]

On 7/26/23 14:56, Mathieu Desnoyers wrote:
> On 7/26/23 13:40, Shrikanth Hegde wrote:
[...]
> > Do you have SMT here? What is the system utilization when you are running
> > this workload?
>
> Yes, SMT is enabled, which brings the number of logical cpus to 384.

Here is an additional interesting data point with nosmt=force on
6.4.4:

hackbench -g 32 -f 20 --threads --pipe -l 480000 -s 100

baseline:                       90s
with idle-delay+nr_running<=4:  87s (3% speedup)

hackbench -g 16 -f 20 --threads --pipe -l 480000 -s 100

baseline:                       52s
with idle-delay+nr_running<=4:  32s (38% speedup)

So the impact of the patch appears to depend on how much the
system actually reaches idle, which does make sense.

Thanks,

Mathieu

--
Mathieu Desnoyers
EfficiOS Inc.
https://www.efficios.com