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preda / gpuowl

GPU Mersenne primality test.
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gpuOwl 7.2 - mild slowdown #200

Closed valeriob01 closed 3 years ago

valeriob01 commented 4 years ago

from 6xx us/it to 706 us/it, exponent 106xxxxxx.

preda commented 4 years ago

Please try with two processes per GPU. While one process has a mild slowdown, two shows a speed-up.

valeriob01 commented 4 years ago

1359 us/it, however this way the GEC time is doubled. Not worth it.

preda commented 4 years ago

Why not worth it? if you run 2 processes in parallel, you should divide all the times by 2; 1360/2 = 680, and doubled-GEC/2 stays the same.

On Sun, 1 Nov 2020 at 20:45, valeriob01 notifications@github.com wrote:

1359 us/it, however this way the GEC time is doubled. Not worth it.

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valeriob01 commented 4 years ago

I prefer the classical way of 1 job per GPU, it makes me feel the system is more stable.

preda commented 4 years ago

Sure that's fine, I also run one GPU in one-task-only. The slowdown is mild, there is a moderated decrease in memory allocation at the same time, and who knows maybe things will improve in the future (i.e. the slowdown being cancelled) hopefully, we'll see.

On Sun, 1 Nov 2020 at 21:36, valeriob01 notifications@github.com wrote:

I prefer the classical way of 1 job per GPU, it makes me feel the system is more stable.

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valeriob01 commented 4 years ago

ROCm 3.9 is out, not testing it for now. I am busy with other things. :-)

preda commented 4 years ago

I tried it, no improvement for me.

On Sun, 1 Nov 2020 at 21:56, valeriob01 notifications@github.com wrote:

ROCm 3.9 is out, not testing it for now. I am busy with other things. :-)

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valeriob01 commented 4 years ago

Mild speedup with latest commit, from 706 us/it to 696 us/it.

valeriob01 commented 4 years ago

Big speedup with carry32, from 696 us/it to 680 us/it.