On Tue, Jan 15, 2013 at 11:38:14AM -0600, Nathan Zimmer wrote:
> 
> Hello Mel,
>     You helped some time ago with contention in lock_pages on very large boxes. 
> You worked with Jack Steiner on this.  Currently I am tasked with improving this 
> area even more.  So I am fishing for any more ideas that would be productive or 
> worth trying. 
> 
> I have some numbers from a 512 machine.
> 
> Linux uvpsw1 3.0.51-0.7.9-default #1 SMP Thu Nov 29 22:12:17 UTC 2012 (f3be9d0) x86_64 x86_64 x86_64 GNU/Linux
>       0.166850
>       0.082339
>       0.248428
>       0.081197
>       0.127635
> 
> Linux uvpsw1 3.8.0-rc1-medusa_ntz_clean-dirty #32 SMP Tue Jan 8 16:01:04 CST 2013 x86_64 x86_64 x86_64 GNU/Linux
>       0.151778
>       0.118343
>       0.135750
>       0.437019
>       0.120536
> 
> Nathan Zimmer
> 
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I realized I forgot to attach the test.

The test is fairly basic.  Just fork off a number of threads each on their own cpu
have them all wait on a cell and measure how long it took for them to all exit.

Usage is ./time_exit -p 3 512

The numbers I have provided where from some runs on a 512 system.  I tried for
a 4096 box but it was being fickle and was needed for some other testing.