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

From: Kirill Korotaev
Date: Fri Jun 02 2006 - 03:49:19 EST


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
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