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Old 2008-10-20, 07:57   #1
ixfd64
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"Danny"
Dec 2002
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Default delay in crediting?

Something quite odd just happened.

My father has a 2 GHz PC in his office that is on all the time but he rarely uses it, so he let me install Prime95 on it since it will not interfere with his work.

However, Lucas-Lehmer tests take a very long time (about 10 weeks for an exponent in the 44M range) to complete on that computer due it having a non-x86 processor with a lower clock speed, so I've opted for trial factoring instead.

Trial factoring an exponent to 69 bits takes about 46 hours on that computer. Since Prime95 is set to have five days of work queued up, it generally has three factoring assignments reserved at any time. It requests a fourth assignment once the current one is almost done, when the expected completion time is only a few hours away.

This is what has been bugging me: on October 17th, the computer requested an assignment at 12:33 p.m. my local time. This means the exponent it was factoring (which was assigned at around 11:00 p.m. on October 11th) should have been returned some time late that afternoon. However, I checked my PrimeNet account report and it seems that the exponent wasn't returned until around noon on October 19th. (I know that an assignment is finished when it disappears from the list and credit gets added.) However, I checked my PrimeNet account report again at around 11:50 p.m. on October 19th and it seems that another assigmnent was finished.

I'm really confused. Is it possible that there was a delay such that an assignment doesn't get credited until a few days later? Could it be possible that a bug caused Prime95 to skip a large part of the factoring assignment? I'm really hoping that it's not due to the latter case.

I guess I'll need to check the results.txt file in order to have an idea what happened. However, in order to check the log file, I'll need physical access to that computer, which I probably won't get for a few weeks. (Hmm, perhaps George should make a version of Prime95 that allows users to check its status remotely at any time.)
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Old 2008-10-20, 17:18   #2
jrk
 
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Possible that the computer was turned off for some time, or that another task was running that was interrupting prime95?
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Old 2008-10-20, 18:07   #3
ixfd64
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That still wouldn't explain why two assignments were returned within just a few hours. Each trial factoring assignment takes around 44 hours on that computer.
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Old 2008-10-20, 18:08   #4
petrw1
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"Wayne"
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Delays in reporting:
- Your machine is down
- The PrimeNet Server is down (as is the case now)
- The PrimeNet Server is busy (usually the first 5 or so minutes after the hour). If you use the default "Minutes between network retries" of 60 then you could get this problem for many hours. You can change it; I understand V5 will NOT use 60.
- The assignment wasn't actually finished (no insult intended). It may take longer than you expected depending on how busy the PC was or the range the assignment happens to fall into. The days of work is (in my experience) NOT an exact science. I find it is pro-active; that is if my last assignment is expected to finish in 5.5 days I am already getting another one. Don't assume that the asking for another implies a previous one was done.

Check status remotely:
- There will be more team controls in V5. Not sure if this is one.
- If you are using XP it has a remote control option. I'm not sure of the details but you can research it
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Old 2008-10-20, 18:17   #5
ixfd64
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Quote:
Originally Posted by petrw1 View Post
- The PrimeNet Server is busy (usually the first 5 or so minutes after the hour). If you use the default "Minutes between network retries" of 60 then you could get this problem for many hours.
Come to think of it, that is probably what happened. Of course, I'll need physical access to the computer to be sure, though.

Last fiddled with by ixfd64 on 2008-10-20 at 18:17
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Old 2008-10-20, 20:11   #6
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George,

Quote:
default "Minutes between network retries" of 60
reminds me to recommend that the default be changed to some integer relatively prime to 60, and far enough away from 60 so as not to be likely to hit the hourly busy period more than twice in a row: 67? 53? 71?

Will this be done in v5?

Last fiddled with by cheesehead on 2008-10-20 at 20:12
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Old 2008-10-20, 20:38   #7
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http://www.mersenneforum.org/showthread.php?t=9434
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Old 2008-10-20, 20:45   #8
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Quote:
Originally Posted by petrw1 View Post
From there: "Already fixed in the new version being beta tested, default value is set to 70."

My first thought was: "Tsk, tsk, will hit the busy period every seven hours! 71 would be better!"

But then I realized that since this is the network retry parameter, it's unlikely to be repeated more than once. The second try, an hour and ten minutes later, will probably work, and then the retry time won't be used again until another connection failure.

Last fiddled with by cheesehead on 2008-10-20 at 20:50
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