Cuda WorkUnits very slow.

Questions and Answers : GPU applications : Cuda WorkUnits very slow.
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Message 884590 - Posted: 12 Apr 2009, 15:55:49 UTC

I've started using Cuda in the last week or so, and at first I was very happy with the throughput, but over the last three days the speeds have gone from 6-8 mins/WU to OVER 1 HOUR/WU!

I've reset, reinstalled, powered off and on, changed every setting I could find in BOINC and swore a lot.

I've looked through the forums, and seem some similar reports, but no solutions.

Anyway, I've noticed a few things about this problem. This is from starting WinXP from a Hard (Power off) restart, with only Boinc running.

Boinc will load, and then the Seti Cuda Exe will run for 10-20 secs at 25% (all of one core), then the Cuda Exe will drop to 0-1%, and reported GPU usage rocket up to 99%. Explorer also climbs up to about 5-15% CPU usage. There is notable slowdown on the whole system at this point.

The CPU timer for the Cuda WU will start to tick overas soon as boinc loads, but shows the WU at about 1-2% completed, then once the Cuda EXE CPU usage drop, it shows the actual completion level, and sits there hardly moving.


The boinc message "page" shows the usual startup stuff.

I've got a Quad core 2.66Ghz, 4 GB memory (@800MHz) running under Win XP 32 SP2.

Video card is a 8800 GTX Ultra (Factory OC'd)

NVidia Video Driver - 181.20
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Message 884598 - Posted: 12 Apr 2009, 16:07:36 UTC

Well, I'm going to reinstall the drivers, can someone please give me the version numbers that are known to work with Boinc 6.6.20 running Seti on a 8800 GTX ultra.

Many thanks in advance for any help.

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Profile Jord
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Message 884599 - Posted: 12 Apr 2009, 16:08:24 UTC - in response to Message 884598.  

Any version above 177.35 (which is the absolute minimum).
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Message 884613 - Posted: 12 Apr 2009, 16:27:02 UTC

Sounds like a textbook description of a VLAR task - like task 1199062255 (from your system). Anything which has a line

WU true angle range is : 0.008017

in the output, where the figure is 0.05 or less, will behave as you describe.

There is a setting in the 'Preferences' dialog (Advanced view, Advanced menu - look on the first tab) so you can choose "Suspend GPU work while computer is in use" - this will get rid of the perceived system slowdown: you can let the GPU work on these tough tasks at more convenient times (like overnight). The setting is also accessible through your Computing preferences on this website (where it says that it will come into effect with BOINC v6.7, but don't worry - v6.6.20 has it already).

Unfortunately, it looks as if the project has given up on any attempt to solve this problem in the forseeable future.
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Questions and Answers : GPU applications : Cuda WorkUnits very slow.


 
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