Keeping The GPU Busy More Often

Domenic
Domenic
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Topic 226269

Hello all,

I am reposting this from the Cafe forum since it sounds like it may get better traction here.

I am wondering if there is a way to keep my GPU crunching without waiting on the CPU. Not sure if this would be something akin to a rewrite of how a WU is created vs just a setting that could be tweaked. Or possibly even just a limitation of BOINC itself.

As far as I understand it, the GPU crunches up to 99%, then the CPU core goes through the results for analysis of some sort. It takes about 6 minutes for my 1080ti to crunch a WU to 99%, and about 5:30 for a single 5950X core to finish the WU. So my GPU is sitting there idle approx 50% waiting on this core. Adding more WU crunching at once I don't think really solves the issue, as the GPU section of the WUs tend to finish up close to each other and the GPU is still sitting idle at certain points.

My question basically becomes is it possible to decouple the WU at that point? Is this a limitation of the WU? Maybe there is some setting that if the GPU is idle, the next WU can start even while the previous WU is being finished? Just a curiosity thing.

Ian&Steve C.
Ian&Steve C.
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You can’t decouple them. But

You can’t decouple them. But you can run 2 WUs at the same time. Stagger them so that you have GPU processing from the second WU running at the time when the first one hits the CPU portion. 

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Tom M
Tom M
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If he uses Linux I wonder if

If he uses Linux I wonder if the mutex version of the boinc manager would help automate that?

Tom M

People before Prophets (or Profits as the case may be...)

 

Ian&Steve C.
Ian&Steve C.
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There is no “mutex version of

There is no “mutex version of the boinc manager” 

 

there was once a mutex built into the SETI special app. But this was an addition to the application, not the manager (or more correctly, the client, since the manager is just a GUI). It needs to be something coded into the app, and to my knowledge, no other project uses something like that. 

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Domenic
Domenic
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Hey all, thanks for the

Hey all, thanks for the responses. Not sure why, but my notifications must've been turned off for messages.

Anyway, I will try the double WU again. I didn't have any success with it last time, but I will see what I can fiddle with to get it to space out.

ExtraTerrestrial Apes
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Yes, there is a certain time

Yes, there is a certain time the GPU is going to be idle at the end of a WU. However, it shouldn't be nearly as much. at least not for "Gamma-ray pulsar binary search #1 on GPUs". I've got a GTX1070 and a 5900X @ 4.05 GHz and the CPU-only crunching takes on the order of 10 s.

You could try to reduce the number of CPU cores BOINC is allowed to use to 99%. And check if other tasks are loading your machine heavily, taking CPU time away from Einstein. Or if you refer to a different app: let us know.

MrS

Scanning for our furry friends since Jan 2002

Domenic
Domenic
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Interesting. I wonder if it

Interesting. I wonder if it is because lately I have been getting the Gravitational Wave units and those soak up more CPU power at the end.

Lately I have just been running E@H and my Windows PC doesn't have a whole lot running in the background, so I regularly see PBO boost around 4.7 GHz. It takes about 6 min for the GPU to work through, then about 5 min for the CPU. I also have a laptop with a 90W 3070 and a 10875H and it takes close to the same GPU time, but about 7 minutes for CPU (makes sense with less head room and being a laptop with limited cooling).

I could always try changing what units I get, but I also would rather just be served what the project would like me to work on, especially since currently the project is only allowed to do GPU tasks. I kinda got pushed by a member of my other project to work on specific units and I would rather get what the project wants done vs what gets me the most credit. Total random tangent, sorry.

Tom M
Tom M
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ExtraTerrestrial Apes

ExtraTerrestrial Apes wrote:

You could try to reduce the number of CPU cores BOINC is allowed to use to 99%. And check if other tasks are loading your machine heavily, taking CPU time away from Einstein. Or if you refer to a different app: let us know.

Generally, it appears you need at least 2 CPU threads free to make sure the CPU has enough "headroom" to process CPU processes at "full speed".  For a 16c/32t CPU I am running 4 threads "free" under the BOINC manager.

Once a Gamma Ray #1 task hit 89+% it should take less than 10 seconds to get to 100%.

This seems to be true across both some Rx 5700 gpus and a 3080 ti GPU.  I am pretty sure it applies to the gtx 1080 I have that is currently offline.

Tom M

People before Prophets (or Profits as the case may be...)

 

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