[POLL] SLAB : Are the 32 and 192 bytes caches really usefull on x86_64 machines ?

Eric Dumazet
2005-12-21T09:12:06Z

I wonder if the 32 and 192 bytes caches are worth to be declared in
include/linux/kmalloc_sizes.h, at least on x86_64

(x86_64 : PAGE_SIZE = 4096, L1_CACHE_BYTES = 64)

On my machines, I can say that the 32 and 192 sizes could be avoided in favor
in spending less cpu cycles in __find_general_cachep()

Could some of you post the result of the following command on your machines :

# grep "size-" /proc/slabinfo |grep -v DMA|cut -c1-40

size-131072 0 0 131072
size-65536 0 0 65536
size-32768 2 2 32768
size-16384 0 0 16384
size-8192 13 13 8192
size-4096 161 161 4096
size-2048 40564 42976 2048
size-1024 681 800 1024
size-512 19792 37168 512
size-256 81 105 256
size-192 1218 1280 192
size-64 31278 86907 64
size-128 5457 10380 128
size-32 594 784 32

Thank you

PS : I have no idea why the last lines (size-192, 64, 128, 32) are not ordered...

Eric