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World Community Grid Forums
Category: Support
Forum: Android Support Forum
Thread: Too big freqency of checkpointing. |
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Thread Status: Active Total posts in this thread: 9
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Dejvus
Cruncher Poland Joined: Apr 1, 2012 Post Count: 5 Status: Offline Project Badges: 
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Hi,
----------------------------------------If there is a possibility to change checkpointing frequency? Currently is very high, what is unnecessary and can destructively affect the flash memory lifetime. Why only 2 minuts? This creates great strain for phone flash. We must remember, that flash memory can survive only a limited number of write cycles, and WCG currently quickly exhausts this limit. It's possible to increase time between checkpoints, or give the user ability to set it own? [Edit 1 times, last edit by Dejvus at Jul 27, 2013 1:55:04 PM] |
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ryan222h
Senior Cruncher Joined: Sep 4, 2006 Post Count: 425 Status: Offline |
We must remember, that flash memory can survive only a limited number of write cycles, and WCG currently quickly exhausts this limit. It's possible to increase time between checkpoints, or give the user ability to set it own? The checkpoints write at most a few Kilobytes of data at a time. Even smartphones have 100's of megabytes or even many gigabytes of storage. The way (good) flash memory controllers work is they don't rewrite over the same spot over and over again. Even with 1000 checkpoints on WCG, the same spot is probably not written over twice on the flash memory. Even if a memory segment should expire, there are usually backup sectors that can take over.  [Edit 1 times, last edit by ryan222h at Jul 27, 2013 2:13:29 PM] |
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Former Member
Cruncher Joined: May 22, 2018 Post Count: 0 Status: Offline |
....and other folks complain that WCG does NOT write frequently enough.....you just cannot please everyone!
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Former Member
Cruncher Joined: May 22, 2018 Post Count: 0 Status: Offline |
Dejvus, you can [IF] the android client has an settings option for "Write to Disk at most every xx minutes" or similar text **. Default is 60 seconds. I've got it at 5 minutes, sometimes 15, above which it has zero performance effect [on PCs].
It has to be stated that I 'thought' all of the memory in these mobiles was flash store and core and sleeping the device would just in situ hold progress in memory. [I] need education on that. ** Scribe, plz take notes ;P A general request to android users (Over 5000 devices were registered as of last night): Could you possible post screenshots of any settings, tasks, progress screens of the agent. Seen a couple posted, but clearly we have a lag here of what can and can not be done on the android agent versus the full blown PC version. A set could be collated in the WCG Wiki for easy reference of others puzzling at this new thing. TIA |
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Former Member
Cruncher Joined: May 22, 2018 Post Count: 0 Status: Offline |
Rob, Don't forget I am referring to CHECKPOINT writing which as far as CEP2 goes many peeps want it MORE frequentyly
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Former Member
Cruncher Joined: May 22, 2018 Post Count: 0 Status: Offline |
Really... never you're caught front of one
----------------------------------------edit: To change it to a military flavored pun. [Edit 1 times, last edit by Former Member at Jul 27, 2013 6:02:33 PM] |
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Former Member
Cruncher Joined: May 22, 2018 Post Count: 0 Status: Offline |
.....nice one Rob
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Dejvus
Cruncher Poland Joined: Apr 1, 2012 Post Count: 5 Status: Offline Project Badges:
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Leaving aside the question of memory usage, why so frequent?
A general request to android users (Over 5000 devices were registered as of last night): Could you possible post screenshots of any settings, tasks, progress screens of the agent. Seen a couple posted, but clearly we have a lag here of what can and can not be done on the android agent versus the full blown PC version. A set could be collated in the WCG Wiki for easy reference of others puzzling at this new thing. TIA I can. :D Can I do this there? |
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Former Member
Cruncher Joined: May 22, 2018 Post Count: 0 Status: Offline |
Why so frequent... it's a general BOINC programmer practice, if small, to set a save point around every minute, if the model/simulations permit. Then the agent can be used to control the frequency down with "Write to disk at most every...".
Whilst, the agent's 60 seconds interval is not of this time anymore with 4-8-16 and more cores. That means there's a quasi perpetual stream of saves and writing to disk is 'Thé' weak point in performance and user impairement. 5 Minutes would be a better default setting to me, but that's been pointed out before, and not heard, since I cannot recollect a response Yes/No/We think about this. Maybe there was... Thanks for the offer on the screenshots of different agent views. Think best to open a thread for that. I'll do that in a little. Then when we have a good collection, the FAQ can be compiled. (please no 8MB HQ images... 640x480 pixel max or whatever the present forum limit is. |
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