Messages in this thread | | | Date | Wed, 18 Jun 2008 16:12:31 +0200 | From | "Daniel K." <> | Subject | RT-Scheduler/cgroups: Possible overuse of resources assigned via cpu.rt_period_us and cpu.rt_runtime_us |
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mkdir /dev/cgroup mount -t cgroup -o cpu,cpuset cgroup /dev/cgroup
mkdir /dev/cgroup/0
echo 3 > /dev/cgroup/0/cpuset.cpus echo 0 > /dev/cgroup/0/cpuset.mems echo 100000 > /dev/cgroup/0/cpu.rt_period_us echo 5000 > /dev/cgroup/0/cpu.rt_runtime_us
schedtool -R -p 1 -e burnP6 & [1] 3309 echo 3309 > /dev/cgroup/0/tasks
At this point I'd expect the burnP6 task to use 5% of the available CPU resources in the cgroup (5000/100000), but the real CPU usage, as reported by top, is 20% This is 4 times the expected result, and as I have 4 cores, I think there is a strong hint of correlation there.
Maybe with a 4 core system there really is 4 000 000 us available for every 1 wall-time second?
However, I have only assigned one core (3) to _this_ cgroup, so I think this cgroup is overusing its assigned resources.
What do you think?
Daniel K.
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