Upgrading to the latest kernel seems to have done the trick.
The shuttle now beats the rambus machine by a handfull of seconds.
Does anyone know how much better the 2.6 kernel will handle hyperthreading?
----- Original Message -----
From: "Eugene de Villiers"
To:
Sent: Friday, February 06, 2004 12:02 AM
Subject: [SLE] Hyperthreading or memory performance
Hi,
I have recently built a new shuttle desktop and was comparing single app
calculation times between it and an older machine. I got some very weird
results, and was wondering if it was partially due to the opperating system
or predominantly the hardware:
Here are the specs:
new machine
Shuttle SB61G2, Intel 865G chipset, P4 3C, 1Gb DDR400 (two 512Mb Geil chips
for dual channel at CAS2.5)
Hyperthreading is on
Running Suse 9.0 Professional with the distribution smp kernel
old machine
Asus P4P800 (I think), P4 2.4C, 1Gb PC1033 (RAMBUS two 512Mb DIMMs )
Runnning Suse 8.1 with the distribution kernel
Now this application I am running is really memory intensive, but I was
under the impression that dual channel DDR400 was not a lot slower than
RAMBUS PC1033.
Timing the old machine running my test job produces
Real time 1m44 sec
CPU time 1m23 sec
Running the same job on the new machine give me
Real time 4m03 sec
CPU time 2m21 sec
I am baffled. I have heard here and there that hyperthreading is not very
good for single process dominated installations, but this difference is
massive.
Anothe weird thing, when I run xosview on the new machine it shows
continuous system activity in CPU0 up near 100%. At the moment I am all for
deactivating hyperthreading and re-installing the kernel. Help would be
appreciated.
How do I check whether dual channel memory is working properly?
Should I use an updated kernel? Which one?
Thanks
Eugene
