Muon - too long run time for a WU, random run times.

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Aegis Maelstrom
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Muon - too long run time for a WU, random run times.

#1 Ungelesener Beitrag von Aegis Maelstrom » 17.12.2011 03:17

Hello,

I am new to yoyo and I have two questions regarding the Muon WUs running times. How different are durations of particular WUs and is the project aware that these times can be too short comparing to the deadlines?

In my recent case, I have a WU which runs on Core2 Duo T5500 for almost 23 hours of CPU time (and more of physical time) and I am now on 93.33% progress. Presently this WU is overdue for over 12 hours. It has been sent to a heavy cruncher with i7-2600K (probably overclocked and running 24/7) who ran it for ca. 4.5 hrs and received an error result "too many results" (but receiving the credits).

My system is stable and not overburdened but I could not meet the deadline. Link to the Work Unit.

Is it possible to mitigate the problem?

Thanks,
a.m.

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Re: Muon - too long run time for a WU, random run times.

#2 Ungelesener Beitrag von yoyo » 17.12.2011 08:40

Hello,

a muon wu needs roughly between 1h and 40h to finish. The deadline is 5 days. I thought this is enough. It is not predictable how long a wu will run. It is an simulation which also depends on previous results on your computer. In one Boinc wu are 2 simulations. If a simulation result is better than any previous on your computer the simulation is 4 times reexecuted with slightly different input parameters. In this case the wu runs longer. So the first wus which you are running are very long.
You can see this behaviour in the progress bar. If the simulations are not reexecuted you get progress jumps of 0% - 33% - 66% - 100%. If the sumilations are reexecuted you have 4 additional steps between 33% and 66% and 100%, as in your example.
All results which are sent back are used also for new wus. Therefore I want to have the wus back fast. Regarding the runtimes 5 days deadline is a good compromise.

yoyo
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Aegis Maelstrom
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Re: Muon - too long run time for a WU, random run times.

#3 Ungelesener Beitrag von Aegis Maelstrom » 17.12.2011 10:23

Hi,
thanks for your fast reply!
yoyo hat geschrieben:Hello,
a muon wu needs roughly between 1h and 40h to finish. The deadline is 5 days. I thought this is enough.
Well, I should beg to differ. One must remember that it is almost certain for the computer to have already other WUs (from this or other projects) in buffer to crunch. They can have a similar deadline to your WU and a lot of time needed to complete as well.
I know Yoyo you are running is a rather niche project with a big number of heavy crunchers running CPUs 24/7 and they will cut it. However, such aggresive deadlines (possible 40 hours of CPU time in 5 days, when these 5 days may be limited to 2-3 days due to other WUs, there might be more WUs which must be completed in high priority etc.) are quite a lot for not-so-heavily crunching machines.
For me, this machine was crunching for ca. 12 hours a day. I think it is not little but it was not enough.

It is of course your choice but you must be aware that you somehow isolate yourself from a number of machines crunching less frequently.

Not to mention that losing 83,896.29 seconds of CPU time (like in my example, almost 1 full day) with no credit granted(!) plus enigmatic steps on a progress bar (starting from 33.33%, then a long wait...) are not encouraging.
Therefore, if I could advise something, I would think of at least adding a second kind of longer running WUs for new machines and less often crunching machines.

Anyway, big thanks for your explanations - I will share this information with my teammates in BOINC@Poland and try to make it more visible. :)

Best Wishes,
und viel Erfolg mit herzlichen Grüßen aus Warschau,
a.m.

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