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



On Dec 6, 2007 6:31 AM, Jim Kronebusch <jim 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
funny.

-- 
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/


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