Multiple Subprojects - Odds of getting a task?

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Mathmusic
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Joined: 18 Apr 15
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I'm fairly new to primegrid, and I was wondering how the server decides to send tasks when you have multiple subprojects selected.

Is it a random chance based on # of projects you have selected and the hardware you are running?

Or does it try and balance the load based on (expected) computation time?

If I had to guess, I would say it is closer to the first option, as I seem to always eventually end up with all my cores running the longest CPU task I have enabled like SoB.
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Michael Goetz

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I'm fairly new to primegrid, and I was wondering how the server decides to send tasks when you have multiple subprojects selected.

Is it a random chance based on # of projects you have selected and the hardware you are running?

Or does it try and balance the load based on (expected) computation time?

If I had to guess, I would say it is closer to the first option, as I seem to always eventually end up with all my cores running the longest CPU task I have enabled like SoB.

It's complicated, but a simplification would be that it's random with a small bias towards sending shorter tasks.

The reason you seem to always seem to be running SoB has little to do with what the server's sending. No matter how many short tasks it sends you, it would seem like it's always running SoB. Assume a scenario where you have only PPSE (LLR) and SoB (LLR) selected. Even if the server sends you 10 times as many PPSE tasks, it will still seem like all you're running is SoB because the SoB tasks are over 500 times longer!

The server does not consider how many hours you've run each project in the past, so the fact that you may have spent 4 days crunching one SoB but only an hour crunching 6 PPSEs doesn't matter. All it considers is what you're requesting right now. So if you're requesting both PPSE (weighting 3) and SoB (weighting 1), you'll be three times more likely to get a PPSE task than an SoB task. Since the PPSE takes 10 minutes vs. the 4 days for the SoB, despite having a greater chance of getting a PPSE task you'll be running SoB almost all the time.

Given the huge difference in run times between the different projects, I don't really recommend letting the server choose for you. You end up not knowing whether your computer will have long or short tasks, which can be inconvenient in some circumstances.
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Mathmusic
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Joined: 18 Apr 15
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ID: 395688
Credit: 341,702,920
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That is basically what I thought. I ended up being a little out of luck for the last challenge because I was a couple hundred hours into some SoB work and did not feel like losing all that computation time.

It's nice to know that there is some small bias toward the shorter tasks, but you are right that it is nearly impossible to tell. If it was 500x more likely to get a PPSE task than a SoB task then it would be more balanced (on average).

I'm working on filling out my set of badges now, so I will stick to similar sized tasks at least.
____________
My lucky numbers are:
5145*2^1349071+1
7188654^65536+1

ID: 86506 |

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