On 24/02/22 05:35, Dave Hansen wrote:
On 2/23/22 15:02, Abhishek Goel wrote:
If needed, I will provide experiment results and traces that were used
to conclude this.
It would be great if you can provide some more info. Even just a CPU
time profile would be helpful.
Average total time taken for SMT=8 to SMT=1 in v5.14 : 20s
Average total time taken for SMT=8 to SMT=1 in v5.15 : 36s
(Observed in system with 150+ CPUs )
It would also be great to understand more about what "hotplug on power
systems" actually means. Is this a synthetic benchmark, or are actual
end-users running into this issue? Are entire nodes of CPUs going
offline? Or is this just doing an offline/online of CPU 22 in a 100-CPU
NUMA node?
No, this is not a synthetic benchmark. This can be recreated with
entire nodes of CPUs going offline. And the online/offline operations
have been performed by simple scripts. The time observed can also be
verified (for individual CPU or the entire system) by observing CPU-
Hotplug trace which provide consistent result as observed by using
the scripts.
