Multiple GPU's

Author	Message
Mike Sherman* Send message Joined: 8 Apr 10 Posts: 12 Credit: 51,406,691 RAC: 0	Message 39090 - Posted: 24 Apr 2010, 4:08:04 UTC When running two or more GPU's in a single computer do they have to be connected in SLI mode. Thanks, Mike ID: 39090 · Rating: 0 · rate: / Reply Quote

Vid Vidmar* Send message Joined: 29 Aug 07 Posts: 81 Credit: 60,360,858 RAC: 0	Message 39093 - Posted: 24 Apr 2010, 7:05:54 UTC - in response to Message 39090. No. ID: 39093 · Rating: 0 · rate: / Reply Quote

Paul D. Buck Send message Joined: 12 Apr 08 Posts: 621 Credit: 161,934,067 RAC: 0	Message 39094 - Posted: 24 Apr 2010, 7:23:48 UTC However, you do have to make sure that BOINC "sees" both and uses both ... most of us have to use the flag in cc config because DA invented a cleaver idea and will not remove it ... bottom line, if there is a difference in the cards in BOINC's opinion it will only use one of the two ... <use_all_gpus>1</use_all_gpus> in the "options" section of the config file, stop and restart BOINC. ID: 39094 · Rating: 0 · rate: / Reply Quote

avidday Send message Joined: 8 Apr 10 Posts: 15 Credit: 534,184 RAC: 0	Message 39103 - Posted: 24 Apr 2010, 15:47:26 UTC It is worth pointing out that the boinc client has a bug with the way it handles multiple NVIDIA GPUs if you use Linux or the new Windows compute driver for Telsas. It causes scheduling and throughput problems if you use the compute mode settings in the driver to control which GPU will be used in a multi-gpu system. I have made the boinc developers aware of the problem and proposed a patch for it, but I don't know when/if they will fix it. ID: 39103 · Rating: 0 · rate: / Reply Quote

Paul D. Buck Send message Joined: 12 Apr 08 Posts: 621 Credit: 161,934,067 RAC: 0	Message 39105 - Posted: 24 Apr 2010, 17:41:12 UTC - in response to Message 39103. It is worth pointing out that the boinc client has a bug with the way it handles multiple NVIDIA GPUs if you use Linux or the new Windows compute driver for Telsas. It causes scheduling and throughput problems if you use the compute mode settings in the driver to control which GPU will be used in a multi-gpu system. I have made the boinc developers aware of the problem and proposed a patch for it, but I don't know when/if they will fix it. Which mailing list did you post your suggestion on? I don't recall seeing it... ID: 39105 · Rating: 0 · rate: / Reply Quote

avidday Send message Joined: 8 Apr 10 Posts: 15 Credit: 534,184 RAC: 0	Message 39113 - Posted: 24 Apr 2010, 21:45:10 UTC - in response to Message 39105. Last modified: 24 Apr 2010, 21:47:57 UTC I got in touch with the developers after posting on the boinc forums (http://boinc.berkeley.edu/dev/forum_thread.php?id=5606&nowrap=true#32282/ is one of the posts if you are interested). ID: 39113 · Rating: 0 · rate: / Reply Quote

Paul D. Buck Send message Joined: 12 Apr 08 Posts: 621 Credit: 161,934,067 RAC: 0	Message 39116 - Posted: 25 Apr 2010, 0:11:45 UTC - in response to Message 39113. I got in touch with the developers after posting on the boinc forums (http://boinc.berkeley.edu/dev/forum_thread.php?id=5606&nowrap=true#32282/ is one of the posts if you are interested). Ah, ok, out of the "normal" channels ... Thanks ... Side note, 6.10.45 seems to be the last "usable" version, the later all seem of have a bad habit of idling a GPU in dual GPU set-ups. ID: 39116 · Rating: 0 · rate: / Reply Quote

Vid Vidmar* Send message Joined: 29 Aug 07 Posts: 81 Credit: 60,360,858 RAC: 0	Message 39125 - Posted: 25 Apr 2010, 9:49:27 UTC - in response to Message 39094. However, you do have to make sure that BOINC "sees" both and uses both ... most of us have to use the flag in cc config because DA invented a cleaver idea and will not remove it ... bottom line, if there is a difference in the cards in BOINC's opinion it will only use one of the two ... <use_all_gpus>1</use_all_gpus> in the "options" section of the config file, stop and restart BOINC. No such flag used here, BOINC 6.10.32, ATI 4870 & 5870 both crunching @ 100% with (and without on some other projects) app_info.xml (lookie). Again, are things that much different in CUDA world? BR, ID: 39125 · Rating: 0 · rate: / Reply Quote

Paul D. Buck Send message Joined: 12 Apr 08 Posts: 621 Credit: 161,934,067 RAC: 0	Message 39132 - Posted: 25 Apr 2010, 16:35:31 UTC - in response to Message 39125. However, you do have to make sure that BOINC "sees" both and uses both ... most of us have to use the flag in cc config because DA invented a cleaver idea and will not remove it ... bottom line, if there is a difference in the cards in BOINC's opinion it will only use one of the two ... <use_all_gpus>1</use_all_gpus> in the "options" section of the config file, stop and restart BOINC. No such flag used here, BOINC 6.10.32, ATI 4870 & 5870 both crunching @ 100% with (and without on some other projects) app_info.xml (lookie). Again, are things that much different in CUDA world? BR, They can be ... One of the problems in multiple GPU set-ups was that GPU 1 always seemed to have a smaller memory reading even when the GPUs were all identical... DA's first code excluded them for a number of versions, or unless you had the flag set when he included it ... If you can run without the flag, well, you better man than I ... :) After he put in that code, I have dropped that line in my cc_config and don't leave home without it ... who knows what whim will take DA next ... ID: 39132 · Rating: 0 · rate: / Reply Quote

Vid Vidmar* Send message Joined: 29 Aug 07 Posts: 81 Credit: 60,360,858 RAC: 0	Message 39133 - Posted: 25 Apr 2010, 18:06:25 UTC - in response to Message 39132. ... If you can run without the flag, well, you better man than I ... :) After he put in that code, I have dropped that line in my cc_config and don't leave home without it ... who knows what whim will take DA next ... Just luckier, I guess, as luck has a lot more to play in BOINC world than "goodness". :D (I consider myself very lucky, after successfully persuading BOINC to run MW on both GPUs and CPU using opti apps via app_info.xml). On that last observation... I wouldn't dare to start imagining what surprises might there be in store for us.. :^) BR ID: 39133 · Rating: 0 · rate: / Reply Quote