what happens when you run 2 distributed computing programs at once?

[tokamak]

since they ask for spare processor cycles, do they battle for them? split them? first one you open gets them all? im sure this has been asked before...

 

[ProviaFan]

Some programs (Folding@Home is the only one I've had experience with that lets you do this, but I believe some others can do it too) allow you to limit the number of cycles they use to a certain percentage (for example, I can tell F@H to use no more than 45% of my CPU capacity, even if no other program needs it; of course, F@H will still yield if another program needs 95% or 100%). When used together, these types of programs typically share very well. Others that do not allow this kind of fine-grained control may or may not share well. You'll just have to pick the two that you want to run, and give it a try to see. Watch them in the task manager; you may end up with both splitting it 50/50, or one may get 75% and the other 25%, or one may hog the whole CPU and not let the other have any. If you have questions about any two specific programs, please ask and I'm certain someone with experience with that pair will be able to help you.

(edit so the other F@H people don't get mad at me: I don't actually limit F@H on my systems to only 45%; I run it at 100%, but for the purpose of illustration, I have pointed out that it is possible to do so )

 

[Confused]

As far as I know, F@H is the only one that has a "throttle". To run other projects alongside, you will have to look/run them together. The thing that comes into play here is priorities. Other than the "standard" priorities that Windows allows you to have (Realtime, High, AboveNormal, Normal, BelowNormal, Low), there are many "sub-priorities", 20 in total if i remember correctly.

Although projects may use the "Low" priority as you see in Task Manager, some (such as Seti@home, Seventeen or Bust) will use priority 4, whereas some like DF (or SoB using True-Idle in the Service Installer) will use priority 1, however they will still show as "low" in TaskManager. The numbers may be a bit off, but the idea is the same. Therefore, to run 2 projects at once, and have them split 50/50 you will need 2 projects that are at the same priority, and this will be seen by the CPU usage in TaskManager.

Of course, if you're talking about a dual CPU machine, then everything changes! You would assign one project to one processor, and assign the other process to the other CPU.


Confused

 

[SlangNRox]

I almost always run 2 programs but I do it so one uses 100%. This allows the secondary program to run while the first is transmitting data or in case the first one crashes. Nothings worse than waking up to a idle cpu.

To expand on what Confused said, I find that dnet rc5-72 uses the lowest priority possible, while sob seems to use a slightly higher priority. But you can make it run at the absolute lowest using the service "thingy" i think.

 

[GeorgeCredland]

Running two copies of Lifemapper works quite well.

The default priority is now set to "Low" with typical
CPU use around 85%. Running a second copy ups
this to 100%.

Two copies on "Low" evenly divides CPU time, or
one copy on "Low" and one copy on "Below Normal"
(via XP task manager) means that one copy runs
at 85% as before, and the other copy picks up the
spare 15%.

George