Software > Operating Systems and Porting
kernel config: page size 4k vs 64k
cchinicz:
Hi guys, any idea of how 4K vs 64K page size can affect phoronix gzip compression test results?
My Dell 5590 with Intel i5 8th gen with 16GB running Fedora 33 finished the test in 46 sec while my Blackbird 4 cores and 32GB also running Fedora 33 did it in 67 secs. I did not expect the i5 to outperform the 4 cores Power9.
MauryG5:
I don't know if this is the case, but I know for sure that a lot depends on the optimization which on Power is usually much lower unfortunately and therefore often these comparisons cannot be made ...
pocock:
For POWER9, are you reporting the speed on a 4k kernel of a 64k kernel?
The i5 will have 4k kernel
How many memory channels on each system?
Do you watch the load on the CPU cores, for example, using top (press 1) or the GNOME System Monitor? Does the test only use 1 core or does it use all available cores?
Notice that the POWER9 architecture is faster for tasks that can be split between all the cores. Some applications only run on a single core.
cchinicz:
Hi pocock, please see answers below.
For POWER9 I'm running on Fedora binary I've downloaded and therefore on a 64K kernel (default for ppc64el), while on the Dell notebook on a 4K kernel (default for x86).
How many memory channels on each system? On the Dell notebook two x 8GB and on the Blackbird 2 x 16GB.
Do you watch the load on the CPU cores, for example, using top (press 1) or the GNOME System Monitor? Yes, when I run the test I see on the monitor load being distributed across the various CPU threads, on both the notebook and Blackbird.
So, the fact that the test results show that the Dell i5 outperforms the Blackbird maybe because of the different page sizes?
See attached the complete test results.
MPC7500:
These results you could compare:
https://openbenchmarking.org/result/2102047-HA-2101296AS71
Only difference: Kernel pagesize and installed RAM and of course the harddisk.
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