Android E@H many computation errors

JKnerdy
JKnerdy
Joined: 3 Sep 19
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Topic 219552

I have been given 49 tasks on Einstein@Home, and nearly all are getting to 60% completion then disappearing after showing "computation error". I believe I have unhidden my phone's info to allow a knowledgeable person to investigate. If you could help me track down the cause, I would be grateful. I'd like to continue helping, but honestly, seeing the numbers around here and the super computer muscle, paired with the apparent inability to complete a task, makes me question if I could even call this helping! 

Holmis
Joined: 4 Jan 05
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I found this error message in

I found this error message in one of the failed tasks:

exceeded elapsed time limit 49834.40 (350000.00G/7.02G)

This is a failsafe function in Boinc that aborts a task if it runs for to long. To complete a task you need to make sure that it gets enough runtime, you have 4 completed tasks so your device is capable of running them. But it only does so with about 10 000 seconds of margin to when Boinc will abort the task because it's taking to long.

Gary Roberts
Gary Roberts
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JKnerdy wrote:... I'd like to

JKnerdy wrote:
... I'd like to continue helping, but honestly, seeing the numbers around here and the super computer muscle, paired with the apparent inability to complete a task, makes me question if I could even call this helping! 

Thanks for starting your own thread.  Everybody has to start somewhere and no matter how small the contribution, every little bit helps.  Holmis has identified the problem and the solution is straightforward.

Your phone shows as having 8 processors (no doubt virtual) and BOINC will try to use them all (if allowed).  The only thing you really need to do is restrict BOINC to a suitable subset so that concurrent tasks don't prevent each other from finishing in the allowed time.  Here is what should allow you to get things running smoothly.

  1. Check your computing preference settings (account->prefs->computing->advanced) and under "Network settings" make sure you have nice low values for the amount of work that is cached - eg 0.5 days / 0.0 days for the two settings.  You can always increase these later (if you need to) when everything settles down.
  2. On that same page under "Processor Usage" set the setting for "Use at most x% of the processors" to 25%.  This will allow only two tasks to run and hopefully they will run faster and so finish within the time limit.

You can (at your choice) make these changes on the website as described and if you do, you need to click update in your local Boinc Manager in order for your client to become aware of the website changes.  Alternatively, you can change the preferences locally in BOINC Manager (Advanced view) and then the client will be informed immediately.  Local preferences override website preferences so no update is needed.  Future changes to those prefs will need to be made locally unless you use the option (in the manager) to revert to website prefs.  There are advantages and disadvantages with either method so you need to choose the one that suits you best and stay with that to perhaps avoid future confusion.

If allowing two tasks to run works well, you could further experiment by changing the % cores setting to 37.5% (or 50%) and allowing three (or four).  Either of those would probably extend the crunch time (maybe by too much) and would certainly use more power and create more heat.  You need to experiment to find the settings that best work for you.  I would really advise starting low and testing, before gradually ramping up the number of threads in use.  If there are problems with two, try just one (12.5%).

Good luck!  Let us know how you get on :-).

Cheers,
Gary.

JKnerdy
JKnerdy
Joined: 3 Sep 19
Posts: 3
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Thank you both for your help.

Thank you both for your help. I think it's good to go now. I'm letting it run one task at a time, takes about an hour for 10%. At least I get to participate some!

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