[CentOS] CentOS 4 and Intel P4 without Hyper-Threading vs. IntelP4 with Hyper-Threading

Wed Apr 20 16:21:43 UTC 2005
Paul Heinlein <heinlein at madboa.com>

On 4/20/05 9:09 AM, Aleksandar Milivojevic wrote:

> BTW, do note that HT processor still has only single core.  Some reports 
> indicate that there's not much advantage of HT over non-HT processors 
> (and consequently not much advantage of running SMP kernel on HT 
> processor).

Fully realizing that the plural of "anecdote" is not "data," I can 
report that enabling HT and running an SMP kernel speeds up parallel 
make operations by 15-20%. E.g., running "make -j2" on P4/HT/SMP is 
slightly faster than "make -j2" on the same processor running a UP 
kernel. It seems like the SMP kernel is better able to keep the core 
busy than the UP kernel.

Other operations, particularly day-to-day desktop stuff, seemingly don't 
benefit much at all.

Paul Heinlein <> heinlein at madboa.com <> www.madboa.com