GPU usage oscillation

Message boards : Number crunching : GPU usage oscillation
Message board moderation

To post messages, you must log in.

AuthorMessage
Sean Arrowsmith

Send message
Joined: 17 Feb 01
Posts: 26
Credit: 4,810,749
RAC: 0
United Kingdom
Message 1404206 - Posted: 17 Aug 2013, 7:16:53 UTC
Last modified: 17 Aug 2013, 7:18:20 UTC

Hello,

I have been try to work out what is happening on one of my PC's
http://setiathome.berkeley.edu/show_host_detail.php?hostid=7068185

The system is AMD X645 with 8Gb memory and GTX460 (1Gb)
I have just wiped the HD and reinstalled Win7, followed by Nvidia drivers 320.49

I put BOINC V7.0.64 (64bit) on and reattached to BAM which downloaded downloaded SETI and Engima. I then installed Lunatics 0.41 64bit installer.

Upon running MSI Afterburner I can see the GPU usage going up and down. ie the usage oscillation at 99% for 7 seconds then drops to 30% for one seconds and then back up to 99% and so on it goes up and down.

None of my other Nvidia PC's do this, is there a reason or a setting for this oscillation

The GTX460 only is set up to crunch SETI MB Cuda WU

Thank you
ID: 1404206 · Report as offensive
Profile MikeProject Donor
Volunteer tester
Avatar

Send message
Joined: 17 Feb 01
Posts: 30506
Credit: 56,741,503
RAC: 31,744
Germany
Message 1404210 - Posted: 17 Aug 2013, 7:28:28 UTC

You probably need to free a CPU core on that host to feed the GPU properly.

With each crime and every kindness we birth our future.
ID: 1404210 · Report as offensive
Richard Haselgrove
Volunteer tester

Send message
Joined: 4 Jul 99
Posts: 11453
Credit: 104,269,736
RAC: 75,665
United Kingdom
Message 1404249 - Posted: 17 Aug 2013, 9:30:44 UTC - in response to Message 1404210.  
Last modified: 17 Aug 2013, 9:44:46 UTC

You probably need to free a CPU core on that host to feed the GPU properly.

Maybe he already tried to free a core, but by mistake used the wrong %age box?

If you set the "Use at most ... %CPU time" control, it will run as described - all CPUs for 7 seconds on, 1 second off at 87.5%

Instead, set that value to 100%, and use the alternative "use at most ... % of the processors" - at 87.5%, that will keep 3 CPUs continuously occupied (on his quad core), and leave one free.

Not that it should be necessary, since he's running Cuda, not OpenCL.

Edit - there was a range of BOINC clients - v7.0.45 thru v7.2.0 - where David (inadvisedly IMHO) made CPU time throttling apply to GPU apps too. Unfortunately, this includes the currently-recommended v7.0.64 which Sean is using.
ID: 1404249 · Report as offensive
Profile jason_gee
Volunteer developer
Volunteer tester
Avatar

Send message
Joined: 24 Nov 06
Posts: 7471
Credit: 90,721,393
RAC: 7,180
Australia
Message 1404270 - Posted: 17 Aug 2013, 11:24:01 UTC - in response to Message 1404206.  
Last modified: 17 Aug 2013, 11:33:10 UTC

...The GTX460 only is set up to crunch SETI MB Cuda WU


Under those circumstances, I'd recommend lifting the application defaults in mbcuda.cfg, for a 460 more or less dedicated running Cuda MB, around:

[mbcuda]
processpriority = abovenormal
pfblockspersm = 4
pfperiodsperlaunch = 200

Also, perhaps check there aren't any crazy unnecessary motherboard utilities, or other background processes you don't want/need, running. Not that erratic usage is a problem, if expected due to using the PC, but annoying if youthink the system is clean & there is other stuff stealing the Bus (Been there ;) ).
"Living by the wisdom of computer science doesn't sound so bad after all. And unlike most advice, it's backed up by proofs." -- Algorithms to live by: The computer science of human decisions.
ID: 1404270 · Report as offensive

Message boards : Number crunching : GPU usage oscillation


 
©2017 University of California
 
SETI@home and Astropulse are funded by grants from the National Science Foundation, NASA, and donations from SETI@home volunteers. AstroPulse is funded in part by the NSF through grant AST-0307956.