Re: [Gems-users] user misses

["Dan Gibson" <degibson@xxxxxxxx>]

Could it be that your working set size fits in 16 caches but not in 4 caches? AKA what are your cache sizes and configurations and what is the data set size?

Also, what mechanism are you using to start/stop simulation?

Regards,
Dan

On Thu, Jul 17, 2008 at 12:01 PM, Huan Fang <huanf@xxxxxx> wrote:

Hi All,


I have met a real strange problem that concerns user misses. When I run
a parallel application on 4cores, the misses are normal:

Total_misses: 3909948
total_misses: 3909948 [ 988120 975421 973131 973276 ]
user_misses: 3864534 [ 951449 972051 970646 970388 ]
supervisor_misses: 45414 [ 36671 3370 2485 2888 ]

98% of total misses  are user misses.

But with 16 core configuration, the application finishes really fast
(only 5% ruby cycles compared to 4-core), and the user misses are close
to 0:
Total_misses: 1597
total_misses: 1597 [ 174 14 1 4 52 34 3 11 80 10 37 36 1105 1 1 34 ]
user_misses: 25 [ 5 0 0 0 3 4 0 0 0 0 0 1 12 0 0 0 ]
supervisor_misses: 1572 [ 169 14 1 4 49 30 3 11 80 10 37 35 1093 1 1 34 ]


I am sure ruby records the same area of the application. But the result
is simply unreasonable. Is there any thing I didn't notice?

-Huan
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