On Tue, Aug 18, 2020 at 08:00:11PM +0530, Muni Sekhar wrote:

Hi all,

I’ve two identical Linux systems with only kernel differences.

What are the differences in the kernels?

While doing kernel profiling with perf, I got the below mentioned
metrics for Scheduler benchmarks.

1st system (older kernel version compared to the other system) benchmark result:

$ perf bench sched messaging -g 64
# Running 'sched/messaging' benchmark:
# 20 sender and receiver processes per group
# 64 groups == 2560 processes run

     Total time: 2.936 [sec]


2nd system benchmark result:

$ perf bench sched messaging -g 64
# Running 'sched/messaging' benchmark:
# 20 sender and receiver processes per group
# 64 groups == 2560 processes run

     Total time: 10.074 [sec]


So as per scheduler benchmark results, clearly a huge difference
between two systems.
Can anyone suggest to me how to dive deeper to know the root cause for
it.

Look a the differences between your different kernels, that would be a
great start :)

good luck!

greg k-h