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drummers-lowrise
1) Message boards : Problems and Help : High CPU usage for GPU apps (Message 155459)
Posted 43 days ago by arakelov
Now wait and see how much it does effect calculation times. If I remember correctly YIELD_SLEEP_TIME= should be adjusted between different GFN's?

Yes, @composite showed these values.
2) Message boards : Problems and Help : High CPU usage for GPU apps (Message 155454)
Posted 43 days ago by arakelov
What I should put on my /lib/systemd/system/boinc-client.service to Boinc start with libsleep.so?


I put this, without the --dir parameter:

ExecStart=/bin/sh -c 'YIELD_SLEEP_TIME="50000" LD_PRELOAD="/home/arakelov/libsleep/libsleep.so" /usr/bin/boinc'

3) Message boards : Problems and Help : High CPU usage for GPU apps (Message 155419)
Posted 45 days ago by arakelov
So the GPU task should be sleeping or yielding or doing something else in addition to polling the GPU. It could be measuring how long it takes for the GPU to finish the computation and then block on sleep() for a millisecond less than that length of time for the next task (so that it polls the driver for just a millisecond), and voila, you'll see that the core isn't busy anymore.

That's interesting, maybe this is why htop always shows "S" next to the "geneferocl" task?



I have little (near null) knowledge about how CPUs and GPUs interact...
After reading your posts I'm not sure if there's any trick to do from my side (like calling the libsleep.so library) other than just waiting for any driver update. By the way, AMD just released a new Radeon driver on Wednesday, but there are no changes with it.

Thanks a lot!
4) Message boards : Problems and Help : High CPU usage for GPU apps (Message 155398)
Posted 47 days ago by arakelov
Thanks stream, I'll patiently wait for driver updates. Anyway, I'm not sure if AMD engineers are aware of this 'bug'. (Should I report it?)
Would this behavior also happen in any other situation (game, mining app...) that intensively uses GPU?
5) Message boards : Problems and Help : High CPU usage for GPU apps (Message 155394)
Posted 48 days ago by arakelov
Sorry for the double post...

I temporarily suspended boinc projects and the I did:

$ cd /var/lib/boinc-client/projects/www.primegrid.com $ LD_PRELOAD=/home/arakelov/libsleep/libsleep.so ./geneferocl_linux64_3.3.3-2 libsleep: Sleep time: 1000usec geneferocl 3.3.3-2 (Linux/OpenCL/64-bit)


So the "sleep time" line is there. So far so good. But then:

No options were specified, using interactive mode: 1. run Generalized Fermat Prime Search benchmarks 2. run specific benchmarks 3. run primality tests 4. run residue tests 5. compute approximate upper limits 6. test probable primality (fast) 7. test primality (slow) 8. compute Selfridge-Hurwitz residue (Fermat number) 1 No compatible OpenCL device found. Device List:


No GPU? Maybe I'm missing some command-line option?


Ok, going with sudo...

arakelov@arakelov-desktop:/var/lib/boinc-client/projects/www.primegrid.com$ sudo LD_PRELOAD=/home/arakelov/libsleep/libsleep.so ./geneferocl_linux64_3.3.3-2 -q 110607414^131072+1 libsleep: Sleep time: 1000usec geneferocl 3.3.3-2 (Linux/OpenCL/64-bit) Copyright 2001-2018, Yves Gallot Copyright 2009, Mark Rodenkirch, David Underbakke Copyright 2010-2012, Shoichiro Yamada, Ken Brazier Copyright 2011-2014, Michael Goetz, Ronald Schneider Copyright 2011-2018, Iain Bethune Genefer is free source code, under the MIT license. Command line: ./geneferocl_linux64_3.3.3-2 -q 110607414^131072+1 Normal priority change succeeded. Testing 110607414^131072+1... Using OCL2 transform Running on platform 'AMD Accelerated Parallel Processing', device 'gfx1012:xnack-', vendor 'Advanced Micro Devices, Inc.', version 'OpenCL 2.0 ' and driver '3406.0 (HSA1.1,LC)'. 11 computeUnits @ 1900MHz, memSize=8176MB, cacheSize=16kB, cacheLineSize=64B, localMemSize=64kB, maxWorkGroupSize=256. Resuming 110607414^131072+1 from a checkpoint (3157707 iterations left) Estimated time remaining for 110607414^131072+1 is 0:10:10 ^Csting 110607414^131072+1... 2284380 steps to go (0:07:34 remaining)


It runs smoothly but still using one core:
6) Message boards : Problems and Help : High CPU usage for GPU apps (Message 155393)
Posted 48 days ago by arakelov
It seems you are also running alot of PPS LLR tasks multi-threaded.

Well, this morning I realised that the recommendation is to run PPS LLR and PPSE LLR not multi-threaded, so I set to 1 the parameter "Max # of threads" in the preferences. So all these "In progress" tasks that you see will run in 1 core each; they are already running this way and indeed my CPU seems to be getting better use, the performance has increased.
Anyway, I think this doesn't affect the GPU tasks (does it?). I can try to run only GPU-based WUs for a while and look at the CPU usage.

It's better to test GFN-17 and higher, lower GFNs may really require more CPU.

Thanks for the suggestions, I'll try to run genefer manually. I'm looking for my first prime, so some months ago I began running short tasks like SGS, PPS, PPSE and GFN-15, GFN-16 and GFN-17-Mega and never saw this high CPU usage until I had to reinstall amdgpu drivers this week (due to Xorg crashes).
Maybe I will have to wait for new driver versions that solve this...

Thanks and regards.
7) Message boards : Problems and Help : High CPU usage for GPU apps (Message 155387)
Posted 48 days ago by arakelov
Thanks Reggie.

I tested your suggestion and the YIELD_SLEEP_TIME seems not to affect anything. I tried 5, 50, 500, 5000 and 50000. GPU still uses 100% of a core.

Currently, for GPU I'm only in Genefer 15, 16 and 17-MEGA. I've just read in that thread that the WU's for these projects are "too small"...

What I can't understand is why this didn't happen to me with older drivers (maybe an option is reverting to them? I can't remember the version...) What change could have been made to the drivers to cause this?

Thanks again!
8) Message boards : Problems and Help : High CPU usage for GPU apps (Message 155371)
Posted 49 days ago by arakelov
Hi! I'm using Ubuntu 20.04 with AMD Ryzen 7 3700X 8-Core Processor + ATI Radeon RX 5500, with recently reinstalled amdgpu drivers.

I'm running genefer 15, 16 and 17 using only GPU, but if I issue htop in a terminal I can see that CPU shows 100% usage for geneferocl application. AFAIK this means that a full CPU core is being used. This sounds strange to me, as BOINC Manager says that Genefer runs with "0.0754 CPUs + 1 AMD/ATI GPU".

I don't remember seeing such a high CPU usage for GPU apps before. What can be happening?

Thanks a lot in advance.
9) Message boards : Sophie Germain Prime Search : Sophie Germain Prime Search (Message 155255)
Posted 60 days ago by arakelov
Thanks Ravi and Michael! I need to refresh the maths behind all this tests to understand a lot of more things...

Best wishes.
10) Message boards : Sophie Germain Prime Search : Sophie Germain Prime Search (Message 155246)
Posted 61 days ago by arakelov
Just a newbie question, and just to understand how do the projects progress:

Why did the search jump from n=666666 to n=1290000? Is there something special about these exponents? Are they more likely to produce SG primers than others?

Thanks a lot!


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