Re: [patch] voluntary-preempt-2.6.9-rc1-bk4-R1
From: Ingo Molnar
Date: Fri Sep 10 2004 - 08:11:06 EST
* Mark_H_Johnson@xxxxxxxxxxxx <Mark_H_Johnson@xxxxxxxxxxxx> wrote:
> 00000001 0.000ms (+0.000ms): spin_lock (get_swap_page)
> 00000001 0.000ms (+0.000ms): spin_lock (<00000000>)
> 00000001 0.000ms (+0.000ms): spin_lock (get_swap_page)
> 00000002 0.000ms (+0.113ms): spin_lock (<00000000>)
> 00010002 0.113ms (+0.000ms): do_nmi (get_swap_page)
> Are you SURE the spin lock counter works properly on SMP systems?
> I did a quick check of yesterday's results:
> # grep -ir '<.*>' latencytest0.42-png/lt040909 | wc -l
> 6978
> # grep -ir '<.*>' latencytest0.42-png/lt040909 | grep -v '<00000000>' |
> less -im
> ...
> No entries that are non zero and lock related.
it works fine here. To double-check i've created a contention testcase:
00000001 0.000ms (+0.000ms): spin_lock (sys_gettimeofday)
00000001 0.000ms (+0.000ms): spin_lock (<000012ce>)
this spin_lock() spun 4814 times before it got the lock.
Linux locking is pretty uncontended on 2-way boxes.
Ingo
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