I have a debian machine at home, and i have given someone an account on there, to do whatever they like with.

However, i would like to restrict them to only have the ability to use 25% of my CPU. They can run stuff at whatever priority they like, and as many processes as they like, but as an absolute maximum, they can only occupy 25% of my CPU.

Any ideas??

I know you say that you'd like to have anything running at what ever priority the person wants but I'd say that the best way to do this would be to use the nice command to set the priority of the program

man renice and man nice should help, renice has the ability to apply a nice value to a program after it has been launched, so a shell script might come in handy.

We use this on a commercial shell server that we run, we haven't found the best way to restrict to the % of the CPU, I still say even if we did I would choose something like nice because sometimes processes spike to say 30% for a second or two while they do something intense, if the process was limited then maybe it might have problems or something.

Shak

the actual process in question is DNET. This doesn't spike, and even if it did, it shouldn't matter, cos it'd just be like it was running on a CPU that was 25% the speed!

Also... the nice value is useful, but it doesn't restrict a process to a percentage of the CPU... it just sets it's processor scheduling priority. If the machine is completely idle except for dnet, it would still run at about 100%. I want it to run at a maximum of 25%.

Ah, totally different context to what I was thinking, when we use processes like that we're usually talking about an IRC bot or something.

Im not sure about dnet, I'd just say don't use it!

Shak

it's not about DNET specifically, it's about any process.... in fact, what i want to do is restrict a particular user to only being able to use 25% of the CPU at any one time.

I'm pretty sure there's a program out there to do this, but i just don't know it's name...

there are some things floating around.

some ideas:

man 1 bash
/ulimit

PAM also has some limits. I know it has a process limit, not sure about cpu usage, though.

there's also:
man setrlimit
(but as you can see, its setrlimit(2) and they're just programming functions.)
; )

Maybe this: http://www.tls-technologies.com/CPU/cpu-intro.html
only linux-i386-2.4x tho.

In response to unSpawn:

so, we all have ideas that kind of go around it, but not quite there. So for now, I guess you can monitor this users activities and use unSpawn's posted proggy to slow down the really heavy ones.

thanks for all the responses guys!! shame it's something as drastic as a kernel patch, but i should have figured that out anyway!

i might take a look at it when i get time... cheers!!