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

Wed Apr 20 16:26:36 UTC 2005
Peter Farrow <peter at farrows.org>

A hyper threaded processor is only a single core CPU.

Its more marketing than performance, however you might as well run an 
SMP kernel on it just 'cause you can ;-)

When you upgrade to your twin Core Opterons, now that would be a good 
machine to run an SMP kernel on


Paul Heinlein wrote:

> 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.