Hyperthreading degrades performance?

Robert Watson rwatson at FreeBSD.org
Thu Aug 25 18:32:44 GMT 2005

On Thu, 25 Aug 2005, Andre Oppermann wrote:

> Robert Watson wrote:
>> On Thu, 25 Aug 2005, Andre Oppermann wrote:
>>> Don't forget better PIV revisions with larger instruction decoder caches, 
>>> better cache prefetching and branch prediction.  I doubt much of the 
>>> improvement is due to our SMP changes.  A real test to find out whether 
>>> it's our work or Intels would be to benchmark an old (pre Nacona) PIV 
>>> running 5.3R and 7.0-current vs. a new one doing the same.
>> Well, given that my test box for this hasn't changed in three years, I 
>> think I can safely argue it's not the hardware :-).
> Ok, you win.  :-)
> Then the effect of HTT should be much better if you would pop in one of 
> the latest PIV revisions.

My test machine aside, I'm quite willing to believe the hardware has 
gotten better though.  :-)

Robert N M Watson

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