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 wanted to run some benchmarks but in fact I spent it
debugging the bugs I encountered during the benchmarking.

First bug caused the freeze of my pc after about 2 hours of running
make buildworld. I thought it was some kind of deadlock and it took me
almost 3 days until I realised it was just a kernel panic. The kernel
was configured to drop to the debugger on panic and because I was
running X on this pc, I only observed freeze of the gui. After I
realised it is kernel panic and got the panic message and backtrace,
it wasn't too difficult to fix the problem.

Then I encountered another bug that caused the make buildworld process
hang. This problem was due to improper handling of zombie processes in
my code. I think I have fixed it, but tested it only once - and it
seems to be fixed.

So the latest status of my project is this: I have been able to run
make buildworld on behalf of a user that has limited %cpu
availability. And it run without causing any panics or other problems.
But I still need to test it more, possibly with different %cpu limits.

Next week I will continue running benchmarks and I will debug the
problems I will encounter.

rudo