Hyperthreading in 6.x ... still frowned upon?

[Chuck Swiger]

Marc G. Fournier wrote:
> In 4.x, it was a 'shut it off' sort of deal .. my new amd64 don't 
> appear to have it enabled, but my older i386 server that I just 
> upgraded to 6.x does:
>
> user     pid %cpu %mem   vsz   rss   tt state start        time command
> root      14 104.0  0.0     0     8  ??  RL    11:38AM   0:55.02 
> [idle: cpu0]
> root      11 99.1  0.0     0     8  ??  RL    11:38AM   0:00.00 [idle: 
> cpu3]
> root      13 99.1  0.0     0     8  ??  RL    11:38AM   0:00.00 [idle: 
> cpu1]
> root      12 98.0  0.0     0     8  ??  RL    11:38AM   0:54.54 [idle: 
> cpu2]
>
> Is it still something that I should disable, and, if so, how in 6.x?
You should test it for the workloads you have, but most of the time, HT 
isn't especially helpful.  AMD64 CPUs come in dual-core format rather 
than HT-enabled.  If you've seen "HT" or "HTT" applied to an AMD system, 
it's likely an abbreviation for "HyperTransport" or "HyperTransport 
Technology".

-- 
-Chuck