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Climate Prediction way down on Mac - 3P tasks
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Billy
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Apr 24, 2009, 12:52 PM
 
It appears that CPDN 3P tasks are running very slowly on Intel Macs. I suggest that you switch back to SM3 or SM3MH tasks where Intel Macs do as well as or better than Windows or Linux. Only run 3P task on Windows or Linux machines. Perhaps the Mac application was poorly compiled.
     
reader50
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Apr 24, 2009, 07:05 PM
 
From your wording, is the speed ok on PPC Macs?
     
mduell
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Apr 24, 2009, 08:49 PM
 
Are the Win/Lin clients GPU-accelerated?
     
Billy  (op)
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Apr 25, 2009, 07:42 AM
 
Originally Posted by reader50 View Post
From your wording, is the speed ok on PPC Macs?
There are no applications for PPC Macs on CPDN.

Those computers should be running Seti optimized applications or be used on other Projects. I believe that they do well on Seti. I don't have one, just going by others' comments.
     
Billy  (op)
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Apr 25, 2009, 08:00 AM
 
Originally Posted by mduell View Post
Are the Win/Lin clients GPU-accelerated?
No. There are no GPU-accelerated applications on CPDN. The top computers are i7 machines running Windows with 8 cores.

I just noticed that around March 12, the top Macintosh computers started receiving 3P tasks. A Mac Zeon is taking quite a bit longer, actually 2x's as long as a Core 2 Duo running windows. And just starting today, the Macintosh computers are that were claiming 1982 credits on a 3P task are now claiming 4600 to 4900 credits (it is variable). But, they only get 1982 credits. Something strange is going on. So, it is not an good task for Macintosh computers. Stay away from 3P!

There is also a problem with the RAC calculation for 3P tasks. It is many times the actual output. So, don't be deceived by a high and increasing RAC on your computer. The opposite is actually true. Your RAC is falling fast.
( Last edited by Billy; Apr 25, 2009 at 10:56 AM. Reason: Additional info on RAC)
     
Billy  (op)
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Apr 28, 2009, 11:36 AM
 
UPDATE

I received these comments from the mods at CPDN:

Looking at your computer, and a couple of quad core Macs, you appear to be correct. The dropoff in speed between hadsm3 type models and hadam3p models is much more dramatic for Macs than any Linux or Windows PC that are comparable. I just sent an e-mail to the programmer, but am unsure when, or if, anything might be done.

AND

The performance difference is expected and this is not so much a case of efficiency. The Intel mac compiler strictly enforces a high and aggressive level optimizations on science applications which has a negative impact on the app. There is no override for this behavior. As a result, we have to perform additional checks on the floating point calculations. This is not a waste of resources. This represents a the realistic throughput of the application the mac.
     
Billy  (op)
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Jun 22, 2009, 02:52 PM
 
Some good news from CPDN for Mac users

"There's good news for Mac users. HadAM3P ran much more slowly on Mac than on Windows and Linux. Tolu has released a new 6.07 version of this model for Mac. It uses a different compiler and should run faster than version 6.06. It will still be helpful to CPDN if members can complete their current HadAM3P models before downloading new ones as they all produce good data for the researchers."
     
reader50
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Jun 22, 2009, 04:52 PM
 
A good indication of a project paying attention to Mac-related problems.

Now if only they'd get a PPC cruncher up again, I could check personally.
     
   
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