[K12OSN] TuxMath test on 8 core machine with teamed NICs 16GB RAM

Robert Arkiletian robark at gmail.com
Thu Dec 6 16:55:01 UTC 2007

On Dec 6, 2007 6:31 AM, Jim Kronebusch <jim at winonacotter.org> wrote:
> Well, as promised, I did a test yesterday afternoon to see how well TuxMath will scale
> on my hardware/network.  To review I have a dual quad core 2.66Ghz Xeon box (8 cores), 6
> 300GB SAS drives in RAID10, 16GB RAM, and 6 GB nics teamed with adaptive load balancing.
>  The the network is configured there are about 15-20 machines per GB connection to the
> server.  This is also running Edubuntu 7.04 with LDM_DIRECTX=true (no encryption) and
> the linux-image-server kernel under 32-bit to recognize the added RAM.
> So I set out yesterday to see how well my setup would run TuxMath on 30 clients
> simultaneously......not good.  I started up 10, things looked great, CPU load averages
> under 10% and RAM under 2 GB.  Then I started 10 more, CPU under 25% (starting to get
> high), RAM under 3GB, and still moving at a decent speed and loading quickly.  Then I
> started 10 more, all hell broke loose :-(  My CPU average started climbing drastically,
> the server came to a halt, all the clients that were running slowed way down, I couldn't
> quit any instance of TuxMath.  The clients would respond to the point of exiting the
> game, then clicking quit, but the app stayed open and would not close.  My CPU average
> climbed to 148% (Not sure how that is possible) with all instances of TuxMath at the
> quit screen.  So even with all instances of TuxMath no longer moving graphics, but just
> sitting at the quit screen, my processor use still kept climbing, while RAM usage was
> still under 4GB.  The only way I could get the system to recover was by killing all
> instances of TuxMath.
> So, I don't think all the problems users are seeing with TuxMath are related to network
> issues.  It appears 15 or so instances of TuxMath on a single machine are the max due to
> escalating processor usage.  The usage seemed to grow exponentially over time with the
> same amount of instances running.  And once overloaded, the system can't recover, even
> when there are no more moving graphics.  And given my system can handle 75 simultaneous
> Firefox sessions with Flash while switching back and forth to OpenOffice (on-line games
> until the teacher walks by) without breaking a sweat at 1280x1024 resolution, I'd
> venture to say the limitation is in the TuxMath code.

Funny I just ran this test with my class 2 days ago. Running k12ltsp
4.2.3EL on a dual Xeon 2.8GHz , 4GB, 10k rpm raid 1 scsi drives with 1
Gb NIC for eth0 server. Simultaneously launched 30 instances of
tuxmath my load average went up to 27, my bandwidth on eth0 hovered
around 0.5-1 Gb and my ram usage went up to almost 3GB (Don't forget I
use IceWM)  The OS and the server seemed to handle it without falling
apart. It was just really SLOW but nothing seemed to break or act

Robert Arkiletian
Eric Hamber Secondary, Vancouver, Canada
Fl_TeacherTool http://www3.telus.net/public/robark/Fl_TeacherTool/
C++ GUI tutorial http://www3.telus.net/public/robark/

More information about the K12OSN mailing list