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Re: C optimization tests - almabench results

Uros Bizjak wrote:
I don't think that 15% faster clock can produce such a difference...

Comparing benchmark results on two different machines is tricky. There are lots of different variables that may be affecting the results.
1) different linux distros
2) different kernel versions
3) different glibc versions
4) different memory architectures
5) different main memory sizes and speeds
6) different disk speeds
7) different processors

The last one in particular may be an issue. You seem to be assuming that all Pentium4s are the same, but they aren't. There are different kinds of Pentium4s with different instruction sets and different performance profiles. For instance, your Pentium4 probably has the hyperthreading feature, whereas the other one probably doesn't. The previous post mentioned it was using a "Northwood" Pentium4. You probably have a "Prescott". There are probably other differences between Northwood and Prescott. If they have different cache sizes, and the program fits in the Prescott cache but not the Northwood cache then that could give significant performance differences.

It is also possible that one of you made a mistake.
Jim Wilson, GNU Tools Support,

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