[RC5] Does Intel hyperthreading help?

Décio Luiz Gazzoni Filho decio at revistapcs.com.br
Mon Aug 18 19:11:57 EDT 2003


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On Monday 18 August 2003 14:52, Jim Reisert AD1C wrote:
> Do either the OGR or RC5 clients gain any benefit from the hyperthreading
> architecture of the newer P4s? I'm about to upgrade from a 1.67 GHz P4 to a
> 3.0 GHz P4 with HT.  Was wondering if I'll see much less than than 2x,
> close to 2x or more than 2x performance improvement on RC5/OGR tasks.

Less than 2x performance improvement, as far as RC5 goes (I'll restrict myself 
to RC5 since that's what I'm familiar with). The RC5 core is completely 
CPU-bound and as such doesn't benefit from HT. Actually you'll see a decrease 
in performance if you happen to force 2 threads to run, since the threads 
will fight over shared resources.

Keep in mind that HT was made for I/O-bound, not CPU-bound situations.

Décio
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