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World Community Grid Forums
Category: Completed Research
Forum: Smash Childhood Cancer
Thread: Very variable run times for SCC |
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Thread Status: Active Total posts in this thread: 7
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RTS48
Veteran Cruncher Bolivia Joined: Aug 2, 2009 Post Count: 1353 Status: Offline Project Badges: 
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I run 3 Mac computers (an iMac quad, a MacBook Pro quad and an old MacBook pro Dual). Generally the WU times are constant at around 2h 30m for the Quads and around 4h for the dual core. Recently, despite the estimated number of Gigaflops being the same, some WUs are suddenly taking ~ 7 hours which is playing havoc with my WU scheduling and requiring manual intervention to prevent 'Too Late". In addition the points yield per hour for these long run WUs drops to around 20 compared with 25 - 30 for the shorter WUs.
----------------------------------------How are the run time estimates done and can they be improved so that there are no nasty surprises? PS Just had 2 WUs that have come in at over 12 hours even though the GFlops are estimated the same as 2h 30m WUs.
Rod Peel
----------------------------------------Santa Cruz Bolivia South America  ,  [Edit 1 times, last edit by RTS48 at Jun 7, 2018 11:28:32 PM] |
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Speedy51
Veteran Cruncher New Zealand Joined: Nov 4, 2005 Post Count: 1326 Status: Offline Project Badges: 
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Have you tried doing a computer restart? Also if you could provide it with unit names this will help people to be able to provide you with assistance. I doubt I can provide you with further assistance as I am not a Mac person
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Former Member
Cruncher Joined: May 22, 2018 Post Count: 0 Status: Offline |
I don't know whether the GFLOPS estimates are updated dynamically or manually, but most of the calculations run in these projects are not deterministic, so there will always be some variation. With some projects it is possible to make a reasonable guess based on some of the parameters to the calculations but, again, I don't know about specific projects.
----------------------------------------Nevertheless, I was intrigued by the level of variation that you have seen, so I ran a few calculations on the couple of hundred recent results that were still displayed as I run quite a lot of SCC. What I saw was this (all for the same machine, details irrelevant) for CPU time (hours): Average: 1.48 Std Dev: 0.19 Max: 2.06 Min: 0.98 That's not perfect, but it doesn't seem too bad to me. I think you were just unlucky.  [Edit: Typo in Average, it's 1.48, not 1.44] [Edit 1 times, last edit by Former Member at Jun 15, 2018 11:25:31 PM] |
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Sgt.Joe
Ace Cruncher USA Joined: Jul 4, 2006 Post Count: 7846 Status: Offline Project Badges: 
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I did the same thing as Apis Tintinabulator to see if I could arrive at similar results. I used the last 300 units I completed today which should be a big enough sample to see if there are any outliers.
----------------------------------------CPU Time Elapsed Time Average 2.517 2.518 Median 2.480 2.480 Minimum 1.650 1.650 Maximum 3.580 3.580 Std Dev 0.347 0.347 These were run across a variety of machines, all running 24/7, all running Linux. None of them are MACS. I don't see anything which looks like an outlier. They seem to be pretty steady in their run times. As you can see, my machines are somewhat slower than Apis's machines. Hope this helps. Cheers
Sgt. Joe
*Minnesota Crunchers* |
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ca05065
Senior Cruncher Joined: Dec 4, 2007 Post Count: 328 Status: Offline Project Badges:
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The majority of my work units run for between 1:55 and 2:30. A few weeks ago I had one which ran for over 9 hours. I had been suspicious of it because of the indicated time to completion. I attempted to correct it by LAIM off, suspend work unit, wait a few minutes, resume work unit, LAIM on. It continued to completion, validated and provided a full quota of points.
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Speedy51
Veteran Cruncher New Zealand Joined: Nov 4, 2005 Post Count: 1326 Status: Offline Project Badges:
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The majority of my work units run for between 1:55 and 2:30. A few weeks ago I had one which ran for over 9 hours. I had been suspicious of it because of the indicated time to completion. I attempted to correct it by LAIM off, suspend work unit, wait a few minutes, resume work unit, LAIM on. It continued to completion, validated and provided a full quota of points. I am just curious it did the work unit finish quicker after you suspended and re-enabled the the task? |
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ca05065
Senior Cruncher Joined: Dec 4, 2007 Post Count: 328 Status: Offline Project Badges:
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I expected the work unit to speed up after resuming. I assumed it had tied itself in knots and would have a 'fresh start'. However it continued in its slow steady progress to completion.
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