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Message boards : Number Crunching : Workunit Memory Estiimates

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Profile Charles Dennett
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Message 6129 - Posted: 7 Feb 2016, 13:15:11 UTC

One of my crunchers is an old laptop with only 1 GB of memory. For most tasks here and on other projects it's ok. Slow, but ok. However, there are some tasks here where it uses all the memory and starts swapping. This freezes the system so I have to power cycle it and abort the task before it starts again.

The last time this happened I looked at the workunit in the client-state.xml file and it looks like the memory estimate for the task was only 50 MB. A couple of other tasks not the same type as the one that used all the memory had the same estimate. However, they did not use the same amount of memory when they ran as the one that froze.

Would it be possible to get a better memory estimate of the tasks? The system is set to allow only 75% of the memory to be used for a task and BOINC will reject a task if it does not have enough memory. I know this works because BOINC rejects some tasks from another project I crunch for for this reason. That project also has tasks of varying memory requirements.

Thanks for your consideration of this.
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Profile Charles Dennett
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Message 6181 - Posted: 13 Apr 2016, 13:00:35 UTC

Just wanted to bump this up to see if someone would respond.
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Message 6188 - Posted: 14 Apr 2016, 13:48:22 UTC - in response to Message 6181.

Just wanted to bump this up to see if someone would respond.


So I'm looking into this and it looks like the memory estimates are actually a bit higher than what my calculations for what they should be. I wonder how restrictive BOINC is when it comes to memory.

For example, doing some rough estimates from the code, the highest memory usage should be somewhere around 5.5e8 and I've set the memory bound to 5.5e9. So I'm not quite sure why this is happening. I'll try and dig a little deeper.

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Message 6189 - Posted: 14 Apr 2016, 15:20:20 UTC

Thanks, Travis. My concern was that the smaller tasks and the larger tasks all say they have the same memory requirement but in reality the larger tasks use a lot more memory. My little cruncher can handle all but the largest tasks. If the memory estimate was closer to what each task actually required, I could turn this one back on for the project. As it is, I have it turned off because every time it gets one of the large tasks, it uses all the memory and swap. and freezes.

Charlie
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Message boards : Number Crunching : Workunit Memory Estiimates