Do you want to partition threads on a CPU?

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mwroggenbuck
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Joined: Tue Mar 24, 2020 12:47 pm

Do you want to partition threads on a CPU?

Post by mwroggenbuck »

This is probably answered elsewhere, but I can't find it. If you see it, please point me to the post.

I have a CPU with 18 threads free. Which of the following configurations would be best for PPD (and explain your logic of your answer).

18 threads, 1 process
9 threads, 2 process
6 threads, 3 process
3 threads, 6 process
2 threads, 9 process
1 thread, 18 process

I don't think I can do fractional threads :D

Any thoughts?

(I would think that 18 threads, 1 process would crunch information the fastest and give the most PPD, but that is only a guess on my part)
JimboPalmer
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Re: Do you want to partition threads on a CPU?

Post by JimboPalmer »

One process of 18 threads (F@H calls them CPUs) should yield the most Points per Day.

The Quick Return Bonus is nonlinear so two processes may do the same science, yet yield less PPD.
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bruce
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Re: Do you want to partition threads on a CPU?

Post by bruce »

I' going to assume to get 18 CPUs, you've taken into account the other threads in a logical manner.

What you cannot predict is whether there will always be a supply of WUs that use all 18 threads/(cpus). With that assumption, yes, 18 is good.

Every project has a range of thread counts that it is allowed to run on. Suppose the only WUs that are available run on CPUs<=16 (or some other number. You'll get that assignment and two threads will be idle for the duration of the processing of that assignment. You might do better with a 9+9 configuration for some percentage of the time. There's no rational way to predict what projects will be available and for what percentage of the time.
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