Re: Kernel 2.6 SMP very slow with ServerWorks LE Chipset

Alan
2006-12-07T11:05:15Z

> As a test of raw CPU power I've been decompressing the kernel tree, with
> a UP 2.6 kernel this takes about 1m 15s, I don't know if bz2 is
> multithreaded but even if it's not I would expect a slight speed increase
> but in fact with a SMP 2.6 kernel it take 13 ~ 26m, with a SMP 2.4
> kernel it takes 1m 28s and with a 2.4 UP 1m 35s.

The 2.4 numbers look correct (slightly slower), the 2.6 numbers do not.

Nothing obviously wrong from the traces however. If you pin the bzip to a
given processor do you get different results according to which CPU ?

(see man taskset for info on the commands)

If you get very different times on the two processors that will be very
useful information.