CPU Core Usage

Moderators: Site Moderators, FAHC Science Team

Post Reply
gadolf
Posts: 20
Joined: Wed Apr 22, 2020 2:32 pm

CPU Core Usage

Post by gadolf »

FAHClient is set to run on Medium power, on a Ubuntu 20.04 server.
CPU usage monitoring shows 100% usage on one of the cores, while the others have smaller loads.
Is this an issue, for example, by concentrating higher heat rates on one portion of the CPU (sorry if this sounds naive or even stupid, but I don't know anything about cpu architecture)
If so, is it possible to change this behavior? What should be the best situation? Having a better distribution of work load among all cores?
Below, graphs from one week monitoring (on 30 May I changed power from full to medium)
Image

Side note: the images I post here are being cropped. Are there any rules I should follow when embedding images?
JimboPalmer
Posts: 2522
Joined: Mon Feb 16, 2009 4:12 am
Location: Greenwood MS USA

Re: CPU Core Usage

Post by JimboPalmer »

There are utilities to prioritize which cores are used when, they are not related to Folding@Home, and will specialized for your PC's Operating System.

Your slider bar has the following settings:
Light = 1/2 the number of threads your CPU(s) can provide.
Medium = All the Threads - 1
Full = All the Threads your CPU(s) can provide.

Some caveats:
If your PC has a GPU, it gets one thread BEFORE the above algorithm.
There are issues with Prime numbers larger than 3, and prime factors larger than 3. (and you thought you would never use that schooling!)
Desktop versions of Windows seem limited to 32 threads, increasingly, you can buy CPUs with more than 32 threads. Linux and MacOS do not have this issue
Tsar of all the Rushers
I tried to remain childlike, all I achieved was childish.
A friend to those who want no friends
PantherX
Site Moderator
Posts: 6986
Joined: Wed Dec 23, 2009 9:33 am
Hardware configuration: V7.6.21 -> Multi-purpose 24/7
Windows 10 64-bit
CPU:2/3/4/6 -> Intel i7-6700K
GPU:1 -> Nvidia GTX 1080 Ti
§
Retired:
2x Nvidia GTX 1070
Nvidia GTX 675M
Nvidia GTX 660 Ti
Nvidia GTX 650 SC
Nvidia GTX 260 896 MB SOC
Nvidia 9600GT 1 GB OC
Nvidia 9500M GS
Nvidia 8800GTS 320 MB

Intel Core i7-860
Intel Core i7-3840QM
Intel i3-3240
Intel Core 2 Duo E8200
Intel Core 2 Duo E6550
Intel Core 2 Duo T8300
Intel Pentium E5500
Intel Pentium E5400
Location: Land Of The Long White Cloud
Contact:

Re: CPU Core Usage

Post by PantherX »

gadolf wrote:...Is this an issue, for example, by concentrating higher heat rates on one portion of the CPU (sorry if this sounds naive or even stupid, but I don't know anything about cpu architecture)...
It isn't an issue for CPUs as they are designed for multiple scenarios of usage. Applications using a single thread are way more common than I would have expected.
gadolf wrote:...If so, is it possible to change this behavior? What should be the best situation? Having a better distribution of work load among all cores?...
Generally speaking, the OS does the scheduling and in most cases, for an average Donor, should be fine. However, in some cases, locking the folding threads to specific threads and other applications to different threads can increase the PPD in a measurable manner. However, that would only be an option for donors who know what they are doing in terms of CPU affinity and priority.
gadolf wrote:...the images I post here are being cropped. Are there any rules I should follow when embedding images?
We tend to use small images (HD) on the forum since not all members have unlimited fast internet. Plus, most issues can be resolved using the log file so using pictures is not very common. BTW, I can't view the image posted and the link takes me to a Google sign-in so can't access that link.
ETA:
Now ↞ Very Soon ↔ Soon ↔ Soon-ish ↔ Not Soon ↠ End Of Time

Welcome To The F@H Support Forum Ӂ Troubleshooting Bad WUs Ӂ Troubleshooting Server Connectivity Issues
MeeLee
Posts: 1339
Joined: Tue Feb 19, 2019 10:16 pm

Re: CPU Core Usage

Post by MeeLee »

Yeah, I can't access the google pic either.
I would recommend you to set the slider to full.
Then set the CPU count to the amount of cores you prefer to be running.
If you have an 8 core, and it gets too hot, you can set the active core count to 6 or even lower, in an effort to fight heat (or electric cost).
It is recommended to keep the count as high as you are comfortable the CPU running at.
Post Reply