How many CPU-Slots?

[SteffenCBC]

Hello,

I run F@H on a Ubuntu machine with 12 CPUs. How many slots should I configure - one or more?

Here is the description of the hardware from the log:

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08:58:17:WU00:FS00:0xa8:        CPU: Intel(R) Xeon(R) CPU E5-1660 0 @ 3.30GHz
08:58:17:WU00:FS00:0xa8:     CPU ID: GenuineIntel Family 6 Model 45 Stepping 7
08:58:17:WU00:FS00:0xa8:       CPUs: 12
08:58:17:WU00:FS00:0xa8:     Memory: 31.29GiB
08:58:17:WU00:FS00:0xa8:    Threads: POSIX_THREADS

Thanks, SteffenCBC

[Neil-B]

One

[PantherX]

Neil-B is correct, a single CPU Slot that has 12 CPUs assigned to it. Since you're on Ubuntu, you might be able to use the GPU if you have it and it supports OpenCL 1.2 and Double Precision.

If you could describe your general system usage, and how long you plan to let it fold, we might be able to offer some tweaks, i.e. if you leave your system running 24/7 and you only occasionally use it, then use 12 CPUs. If you frequently use it for light work but leave it on 24/7, then maybe using 10 CPUs leaving 2 CPUs for the OS and your light applications could work better.

[JimboPalmer]

Welcome to Folding@Home!

Because F@H rewards quick return of Work Units, one slot of 12 cpus will earn more points than two slots of 6 cpus each, etc.
In Windows, there are issues above 32 cpus.

[SteffenCBC]

Thank you! My computer is located in my living room and also serves as my music provider, it runs only the time I'm awake . But the other users of the room find it sometimes quite loud, so I need to switch between 1 CPU and more, usually 10.

Therefore I would like the control panel to offer me another choice: 1 CPU. Then I could switch the folding power between the existing light (5 CPUs), medium (10 CPUs) and full and - my choice - ultra light (1 CPU), when others are around. My solution now for this is: I have two CPU slots, one of 9 CPUs and one of 1 CPU. If there is the need to pause the big folding, I pause the first slot only.

I also used the GPU for F@H, but it slows down the graphics when I'm using the computer for other tasks. The folding client unfortunately misses the feature to pause folding while the user is active, so I use the GPU only for task provided by BOINC, which has this feature. This would be a great feature for F@H!

[gunnarre]

But the other users of the room find it sometimes quite loud, so I need to switch between 1 CPU and more, usually 10.

Folding benefits greatly from using many threads, more so than just CPU clocks, so you might perhaps want to control the fan speed and CPU frequency boosting rather than switching between a different number of folding threads. Dumping or delaying WUs also negatively impacts your throughput. Going down from 10 to 1 thread will dump the work unit, perhaps unless you have multiple slots. If you have some program that can switch between fan profiles and CPU power profiles at the push of a button, this might hurt the science throughput less than constantly switching the number of threads.

My living room PC has an oversized CPU cooler, which is less loud than the ventilation and any sound played, so it can fold constantly without any annoyance. Only the GPU is slightly audible, and I can pause that individually if needed.

The folding client unfortunately misses the feature to pause folding while the user is active, so I use the GPU only for task provided by BOINC, which has this feature. This would be a great feature for F@H!

Folding@Home already has idle detection, so that it can fold only when the user is inactive. However, this functionality is dependent on the operating system, and it doesn't always work.

[Neil-B]

The idle function works fine in Windows but since OP is Ubuntu I wasn't sure what the configuration is to get it working for that

[SteffenCBC]

Ok, I will give the idle function another try. And then I will look after fan profiles. I guess the computer was designed as a working machine, not a living room silent machine, but I was not aware of that at the time I was buying it.

[bruce]

Apparently you have determined that 1 CPU thread is silent and any higher number is too noisy. I would reconfirm if 2 or 3 is or is not acceptable.

Most modern CPUs do a degree of self-regulation. Running with 10 threads (whether configured as 1 + 9 or as 10) will probably run at a lower clock rate than running with only 1 CPU (assuming you have not adjusted various custom CPU settings which result in fan speed as well as what's called "boost"). That clock rate is set based on the total power (heat) being used.

It should be noted that if you choose the [1] vs. the [two slot 9 + 1] any WU which is downloaded by the single-threaded slot will be permanently use only one CPU so it's processing will continue to be very slow. The number of threads can never be increased above the number that your slot told the server you would be using.

[gunnarre]

I guess the computer was designed as a working machine, not a living room silent machine, but I was not aware of that at the time I was buying it.

What case is it in and which CPU cooler is in there now? Perhaps there's room for a quieter cooler.

[PantherX]

While upgrading the CPU cooler would get you the best of both (performance and noise), there's another option where you simply only use 6 CPUs to see if that's acceptable or not when it comes to the noise. Reason is that you have 6 physical cores which provides the maximum performance boost for F@H since the virtual cores provide a significantly less performance boost.

[SteffenCBC]

Let's see, what I have found so far:
1. The idle mode does not work under Ubuntu, perhaps it waits for hibernation instead of a locked screen.
2. I can measure several core temperatures, but I cannot configure the fan speed: /usr/sbin/pwmconfig: There are no pwm-capable sensor modules installed. To be honest, I feel a bit uneasy about adjusting fan speed.

The case is HP Z420 workstation, it seems I am unable to find out more about the cooler without opening the case:

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# dmidecode 3.1
Getting SMBIOS data from sysfs.
SMBIOS 2.7 present.

Handle 0x0067, DMI type 27, 15 bytes
Cooling Device
	Temperature Probe Handle: 0x0066
	Type: Power Supply Fan
	Status: OK
	Cooling Unit Group: 1
	OEM-specific Information: 0x00000000
	Nominal Speed: Unknown Or Non-rotating
	Description: Cooling Dev 1

It may take some time, before I open the case.

[PantherX]

For Ubuntu, see how the OS defines idle since that's what the client uses. Last I checked, there's may different ways that idle is defined on Linux.

[SteffenCBC]

Ok - how do I do that?

[PantherX]

Sorry, I have no experience on Linux when it comes to folding only when idle However, there might be other Linux members here who can help you out