Re: [ckrm-tech] [RFC 3/5] sched: Add CPU rate hard caps

[Kirill Korotaev <dev@openvz.org>]

>>>> Sure! You can check OpenVZ project (http://openvz.org) for example 
>>>> of required resource management. BTW, I must agree with other people 
>>>> here who noticed that per-process resource management is really 
>>>> useless and hard to use :(
>>
>>
>> I totally agree.
> 
> 
> "nice" seems to be doing quite nicely :-)
I'm sorry, but nice never looked "nice" to me.
Have you ever tried to "nice" apache server which spawns 500 
processes/threads on a loaded machine?
With nice you _can't_ impose limits or priority on the whole "apache".
The more apaches you have the more useless their priorites and nices are...

> To me this capping functionality is a similar functionality to that 
> provided by "nice" and all that's needed to make it useful is a command 
> (similar to "nice") that runs tasks with caps applied.  To that end I've 
> written a small script (attached) that does this.  As this is something 
> that a user might like to combine with "nice" the command has an option 
> for setting "nice" as well as caps.
> 
> Usage:
>         withcap [options] command [arguments ...]
>         withcap -h
> Options:
>         [-c <CPU rate soft cap>]
>         [-C <CPU rate hard cap>]
>         [-n <nice value>]
> 
>         -c Set CPU usage rate soft cap
>         -C Set CPU usage rate hard cap
>         -n Set nice value
>         -h Display this help

the same for this. you can't limit a _user_, only his processes.
Today I have 1 task and 20% limit is ok, tomorrow I have 10 tasks and 
this 20% limits changes nothing in the system.

Kirill