[Haskell-cafe] Shootout favouring C

Ben Lippmeier Ben.Lippmeier at anu.edu.au
Mon Jan 16 19:54:04 EST 2006

Daniel Fischer wrote:
> However, I'm curious. Is the behaviour I reported peculiar to my flavour of 
> linux, or does the same trend show on other machines?
> Would you be so kind to test and report?

For doing benchmarks with short runtimes on linux, you might want to 
double check that the CPUSpeed daemon isn't changing your clock rate 
while you're trying to do your measurements.

Modern AMD chips, and some mobile Intel chips have clock rate scaling. 
The CPUSpeed daemon on my AMD64/Fedora4 machine scales the clock rate 
between 1 and 2Ghz depending on system load.

Send the daemon SIGUSR1 to force maximum speed, and check /proc/cpuinfo 
to make sure.

This has certainly confused me in the past.


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