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  • Latest Post - ‏2011-08-24T12:10:23Z by rakihere
10114 Posts

Pinned topic strange benchmark results

‏2006-09-14T06:19:40Z |

I am currently doing some benchmarks on PPE with JamVM, an open source Java Virtual Machine. I use the Java Grande Benchmark Suite, which supports multi-threaded testing. I have tried several benchmarks with the same results,
I do not really understand.

Here are the numbers for the Crypt Benchmark (e.g.)

1 thread: 228.72 KBytes/s
2 threads: 454.76 KBytes/s
3 threads: 634.02 KBytes/s
4 threads: 831.04 Kbytes/s
5 threads: 685.56 <= Kbytes/s
6 threads: 762.28 Kbytes/s
7 threads: 764.87 KBytes/s
8 threads: 783.63 KBytes/s

There are 2 things I cannot understand:
- It seems, that for all benchmarks I have tested so for, that performance
increases approximately linear until 4 threads. The performance of 5 threads
is worser that with 4 or 6 threads!? What might be the reason for that?
Other Benchmarks, like SparseMatrixMult, etc.. show similar behavior.

-I have tested the same application with JamVM on a X86 core duo. Increasing
the number of threads does not result in significant performance gains.
My second question: Why does PPE show performance gains and X86 not?
I do not think that is a VM or application specific problem.

Thanks for ay comments,


Updated on 2011-08-24T12:10:23Z at 2011-08-24T12:10:23Z by rakihere
  • rakihere
    4 Posts

    Re: strange benchmark results

    HI Could u please tell me the procedure to use jamvm in cell sdk. Thanks in advance