cpu limits status report

[rudo tomori]

Hi,
the goal of my gsoc project is to enable the system administrators to
configure %CPU limits using the rctl command. So that they can for
example limit a particular user to 50% cpu time.

Last week I updated the formula that calculates the %cpu process
utilization. I now use the same formula that is used in the ps(1)
command. In the ps(1) command, the exp(x) and ln(x) floating point
functions are used. To avoid this in kernel, I used fixed point
arithmetic and a precomputed table of exp(x) values for a specified
range.

I also fixed the problem with per-used %CPU utilization that I
mentioned in the previous status report.

This week I am going to test the per-process %CPU limits on real hw
because I do the development on virtual machines. If I encounter any
problems, I will try to solve them. After that I will start working on
per-user %CPU limits.

rudo