Hi,
There is a huge performance regression on the 2 and 4 NUMA node systems on stream
benchmark with 4.17 kernel compared to 4.16 kernel.
Stream, Linpack and NAS parallel benchmarks show upto 50% performance drop.
When running for example 20 stream processes in parallel, we see the following behavior:
* all processes are started at NODE #1
* memory is also allocated on NODE #1
* roughly half of the processes are moved to the NODE #0 very quickly.
* however, memory is not moved to NODE #0 and stays allocated on NODE #1
As the result, half of the processes are running on NODE#0 with memory being still
allocated on NODE#1. This leads to non-local memory accesses
on the high Remote-To-Local Memory Access Ratio on the numatop charts.
So it seems that 4.17 is not doing a good job to move the memory to the right NUMA
node after the process has been moved.
----8<----
The above is an excerpt from performance testing on 4.16 and 4.17 kernels.
For now I'm merely making sure the problem is reported.
Thank you.
Best regards,
Jakub Racek
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