Re: 2.6.0-test4 shocking (HT) benchmarking (wrong logic./phys. HT CPU distinction?)

[Andy Isaacson]

On Tue, Aug 26, 2003, max@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx wrote:
> in our fine physics group we recently bought a DUAL XEON P4 2666MHz, 2GB, with
> hyper-threading support and I had the honour of making the thing work. In the 
> process I also did some benchmarking using two different kernels (stock 
> SuSE-8.2-Pro 2.4.20-64GB-SMP, and the latest and greatest vanilla 
> 2.6.0-test4). I benchmarked 
> 
> [2] running time of a multi-threaded numerical simulation making extensive use
> of FFTs, using the fftw.org library.

One thing to watch out for, with fftw:  I believe it will benchmark
various kernels, and decide which one to use, at run-time.  If the
scheduler fools it into thinking that a particular kernel is going to
perform better, it might do the wrong thing.

Does fftw have a switch to write a debug log?

("kernel" in this context means "the small section of code used to solve
the fft", not "the OS code running in privileged mode".)

-andy
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