Using hyperthreading on 2 Proc Xeon cluster nodes

Ole W. Saastad ole at
Sun Jun 9 00:18:38 PDT 2002

I have tested the Xeon Hyper threading performance in orde...
check Intel's claim about a 10-30 % increase in performance.
I used the OpenMP version of NAS and the meteo code mm5.
(The latter can take advantage of ScaMPI's thread-safeness
and run with a combination of OpenMP and MPI).

Except for one benchmark (NAS EP) I saw no significant increase
in performance and the use of hyper threading for Floating point
work is limited. Most probably because the Xeon proc. is starved
for exec. units. Newer Pentiums might have more exec. units and
there might be a speedup for floating point work. However, for
the EP benchmark which uses transc. functions there is a
significant speedup and a given application might benefit from
hyper threading.


Ole W. Saastad, Dr.Scient. Scali AS P.O.Box 150 Oppsal 0619 Oslo NORWAY
Tel:+47 22 62 89 68(dir) mailto:ole at
Are you meeting Petaflop requirements with Gigaflops performance ?
    - Scali Terarack bringing Teraflops to the masses.

More information about the Beowulf mailing list