2.6.24-rc2 slab vs slob tbench numbers

[Nick Piggin <nickpiggin@yahoo.com.au>]

Hi,

Just ran some tbench numbers (from dbench-3.04), on a 2 socket, 8
core x86 system, with 1 NUMA node per socket. With kernel 2.6.24-rc2,
comparing slab vs slub allocators.

I run from 1 to 16 client threads, 5 times each, and restarting
the tbench server between every run. I'm just taking the highest
of each of the 5 tests (because the scheduler placement can
sometimes be poor). It's not completely scientific, but from the
graph you can guess it is relatively stable and seems significant.

Summary: slub is consistently slower. When all CPUs are saturated,
it is around 20% slower. Attached is a graph (x is nrclients, y
is throughput MB/s)

If I can help with reproducing it or testing anything, let me know.
I'll be trying out a few other benchmarks too... anything you want
me to test specifically and I can try.

Thanks,
Nick

Attachment: slab.png
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