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Old 2021-08-14, 14:47   #12
kriesel's Avatar
Mar 2017
US midwest

577110 Posts

Originally Posted by Jonnymac View Post
Hi axn, Task Manager's Processes tab does show GPU utilization, however both Gpuowl and mfaktc show 0%
Windows Task Manager support for GPU resource usage is a relatively recent addition (~2017 fall creator's update) and won't display unless the window is wide enough and certain columns are enabled. It seems to count Windows & GUI application demands on GPUs, but not OpenCL computation from a command-line (GUI-less) application such as Gpuowl, CUDALucas or mfaktx.
I have systems with multiple GPUs running saturated with mfaktx or gpuowl, and Windows10 typically shows GPU usage at ~3% total, while GPU-Z or utilities provided by AMD, NVIDIA, EVGA, MSI, etc, show them each at ~100%.
Windows' identification of GPU# in the GPU engine column is also um interesting. Usually it's GPU 0, but I just saw "GPU 8 - copy". There are not 8 or 9 GPUs on any system I own, so it's unclear how it's getting to 8. That's on a 6-PCIe slot motherboard, with 5 occupied so the onboard VGA doesn't have to be turned off, with a single 1-to-4 PCIe expander card, and being accessed via remote desktop, so maybe #8 is the remote desktop virtual adapter.

Nvidia-smi seems reliable for indicating GPU loading, and is also useful for power management, and being a command-line utility, also introduces very low overhead if only used when stats are wanted, leaving more cycles for prime95 or whatever.

There are also anomalies regarding CPU usage if running WSL and Mlucas or whatever; Linux top shows heavy CPU usage (~9 of 12 hyperthreads total), but the Ubuntu process listed in Windows Task Manager shows essentially zero, while overall CPU usage indicated in Task Manager is high (50-100%) and consistent with the concurrent Linux top output.

Also what does -1,79,2,3,1 mean at the end of the PRP assignment?
See the worktodo entry formats post in the reference info.

Last fiddled with by kriesel on 2021-08-15 at 13:17
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Old 2021-08-15, 01:28   #13
moebius's Avatar
Jul 2009

11548 Posts
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Originally Posted by Jonnymac View Post
Thanks Matthew,

QQ I am running Gpuowl with maxAlloc 7G however my task manager shows GPU utilization < 3%!!!
Is there a flag I need to run to make Gpuowl use the GPU instead of the CPU?

Also what does -1,79,2,3,1 mean at the end of the PRP assignment?
Assuming it's something to do with cores or cpu's but unsure how it is relevant to GPU
Use GPU-Z from Techpowerup to show your GPU-LOAD, for me from 99 to 100% at my RX VEGA 64

Last fiddled with by moebius on 2021-08-15 at 01:32
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Old 2021-08-15, 02:48   #14
"University student"
May 2021
Beijing, China

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Originally Posted by Jonnymac View Post
Also what does -1,79,2,3,1 mean at the end of the PRP assignment?
1,2,p,-1 means 1*2^p+(-1) = 2^p-1
79: No factor below 2^79
2: A P-1 test is needed, 2 tests will be saved if a factor is found
3: Base number 3 (compute 3^(2^p-2))
1: Type 1

Last fiddled with by Zhangrc on 2021-08-15 at 02:50
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Old 2021-08-15, 16:49   #15
Romulan Interpreter
LaurV's Avatar
Jun 2011

24·13·47 Posts

Originally Posted by axn View Post
...Task Manger...
That's either a box from which all tasks are eating, or an odious application which is eating your tasks! Stay away!

(sorry, I could not stop myself)
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