I have run some tests on a quad-core Intel Core2 Q6600 / linux 64 bit
machine.
On Fri, 9 May 2008, s.haenger@[EMAIL PROTECTED]
wrote:
> Hi,
>
> I have a Problem with IDL 7.0
> We have to multiply large matrices. With some matrix sizes, the CPU
> usage is 100% but for most of the matrices it is 50%. (I'm runnning it
> on a Intel T7250 (Dual Core, 2GHz, 2MB L2 Cache))
>
>
> The CPU System Variable is configured like this:
> IDL> print, !CPU
> { 0 0 2 2
> 100000 0}
>
>
> Now we do this:
> matA = randomn(42, 2000, 2200)
> matB = randomn(43, 2020, 2000)
> matIdl = matA##matB
>
> So now i've got a CPU usage of 100%
>
# of threads IDL 7 time
1 12.476210
2 6.5931890
3 5.2085290
4 4.9191489
it scales well for two cores, so the CPU usage should be near 100% for two
threads.
> but with this:
> matA = randomn(42, 2500, 2500)
> matB = randomn(43, 2520, 2500)
> matIdl = matA##matB
>
> the cpu usage is around 50%-60%
# of threads IDL 7 time
1 22.034877
2 11.681226
3 9.7771089
4 9.3093379
again, CPU usage should be near 100% for two cores.
Just for comparison, ATLAS (http://math-atlas.sf.net)
times:
# of threads IDL 7 time
1 4.4285851
4 1.1784132
and
# of threads IDL 7 time
1 7.8148808
4 2.1345751
regards,
lajos
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