Posted Sep 26, 2007 10:16 UTC (Wed) by epa
In reply to: 64 processors?
Parent article: What every programmer should know about memory, Part 1
I don't think that is a fair comparison. You would need to compare running two perl tasks in parallel with HT versus running two in parallel without HT. That will tell you whether HT itself gives any performance improvement for parallel-perl workloads, and so may give a clue about whether to enable it on a production web server (which presumably is running lots of perl jobs at once).
Whether your two programs are best scheduled in parallel or serially is another question - as you found out, it may be faster to run one then the other. This does not necessarily imply that hyperthreading should be turned off.
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