Linus, Alan, could you please drop them. Switching from 1 list to 3
lists is just a slowdown.
km(1) 0x87 0x89
kf(1) 0xa9 0xa8
kf(cachep, 1) 0xad 0xad
km(4096) 0x7B 0x87 (+24% without overhead!)
kf(4096) 0xcB 0xd1
kf(cachep,4096) 0xcc 0xd3
(cpu ticks on a Duron 700, UP kernel, 100 calls in a tight loop, loop
overhead (0x49) not removed)
Benchmarking with SMP kernel is meaningless, since the actual list
changes are outside of the hot path - I did it, and the differences are
negligable (+-1 cpu tick)
And this is a benchmark with 100 calls in a tight loop - Andrea's patch
adds several additional branches, in real-world there would be an even
If there are real performance problems with the slab, then the not-yet
optimized parts should get changed:
* kmalloc(): the loop to find the correct slab is too slow. (the numbers
in the table are without the loop, i.e.
* finetune the size of the per-cpu caches
* finetune the amount of pages freed during kmem_cache_reap()
* replace the division in kmem_cache_free_one() with a multiplication.
(UP only, on SMP outside of the hot path)
* enable OPTIMIZE - could help on platforms without a fast
virt_addr->struct page lookup.
I have a patch with some optimization, but I tought that would be 2.5
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