Forum > GPU crunching
x38g reports
Jason G:
As far as I'm concerned, x39d & e are different on those particular cards to x38g, and it's those family of 'newer' cards that brought us into x39 diagnostic builds trying to locate a specific issue with those GPUs (& some others).
My current suspicions are along the lines that x38g & earlier builds, on certain cards & drivers ,can have some silent failures, that while not necessarily manifesting in obvious reportable count differences can certainly lead to differences in the best signals.
With regard to the likelihood that some such hidden error exists, with x38g it's possible, while with x39d highly unlikely. In other words while the computation codepaths are basically the same, the driver version & kernel reliability cross GPU is not, which is why we are running 'diagnostic' builds & not optimising for performance at this point.
Jason
perryjay:
Hey boss, just wanted to let you know, Raistmer, Claggy and Ghost made me do it!!! They ganged up on me! ::)
Only kidding, but I am running Raistmer's new app for APs on NVidia GPUs. Ghost said it was running okay on his with two MBs running at a time so I guess I will find out if three at a time will work. Haven't got any work for it yet but I'll let you know how it goes.
Jason G:
OK. If it pinches all the CPU from the Cuda app, starving it out, blame Raistmer.
Claggy:
--- Quote from: Josef W. Segur on 29 Jun 2011, 01:03:15 pm ---
--- Quote from: perryjay on 29 Jun 2011, 10:23:47 am ---Going for a fourth http://setiathome.berkeley.edu/workunit.php?wuid=766762437
I agreed with another running x38g while a stock 6.03 found an extra gaussian. The x38g was first, I was third. Shouldn't I have validated him?
--- End quote ---
Yes, x38g on a GTX 460 and x39d on a GTS 450 really ought to be so close that an inconclusive comparison is nearly impossible. IMO the tiny likelihood of one of the reported or "best" signals being at a critical level should be much rarer than necessary to explain the number of inconclusives that are happening even between stock and the x3[8|9] builds.
Edit: Attaching the WU for that particular case. I have no way of comparing x38g to x39e unless someone else tests. I could do a CPU test, but won't unless CUDA testing seems to indicate it's needed.
Joe
--- End quote ---
Here's a benchrun comparing x39e to x32f and x38g,
Edit: x39e was Weakly similar against x32f, but Strongly similar, Q= 99.96% against x38g
Edit 2: did an x38d run too, x39d was Weakly similar against x32f, but Strongly similar, Q= 99.97% against x38g
Claggy
Jason G:
Looks like the chirp difference to me altered the best gaussian, as opposed to more recent x39 changes.
I'll run that one on AKv8b for a double precision CPU chirp reference comparison.
(Barring the mentioned reliability issues we're looking for, x38g & x39d/e should have matched one another in this case)
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version