Messages in this thread | | | Date | Wed, 11 Jul 2012 14:16:59 -0500 | From | Seth Jennings <> | Subject | Re: [PATCH 0/4] zsmalloc improvements |
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On 07/11/2012 02:03 AM, Minchan Kim wrote: > Today, I tested zsmapbench in my embedded board(ARM). > tlb-flush is 30% faster than copy-based so it's always not win. > I think it depends on CPU speed/cache size.
After you pointed this out, I decided to test this on my Raspberry Pi, the only ARM system I have that is open enough for me to work with.
I pulled some of the cycle counting stuff out of arch/arm/kernel/perf_event_v6.c. I've pushed that code to the github repo.
git://github.com/spartacus06/zsmapbench.git
My results were in agreement with your findings. I got 2040 cycles/map for the copy method and 947 cycles/map for the page-table method. I think memory speed is playing a big roll in the difference.
I agree that the page-table method should be restored since the performance difference is so significant on ARM, a platform that benefits a lot from memory compression IMHO.
Still, the question remains how to implement the selection logic, since not all archs that support the page-table method will necessarily perform better with it.
Thanks, Seth
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