RFR: 8197589: CPU count wrong when both cpu shares and quotas are used

[Bob Vandette]

Updated webrev URL.


> On Feb 12, 2018, at 2:41 PM, Bob Vandette <bob.vandette at oracle.com> wrote:
> 
> Please review this change to the cpu count selection logic used when running in docker containers.
> 
> BUG:
> 
> https://bugs.openjdk.java.net/browse/JDK-8197589
> 
> WEBREV:
> 
> http://cr.openjdk.java.net/~bobv/8197589/webrev.00/
> 
> The algorithm implemented in JDK-8146115 for selecting the number of active cpus assumed that a container 
> would not be configured to use both cpu shares AND cpu quotas at the same time. This was an invalid assumption 
> since this how containers are configured to allow bursting activity [1].  A Java process running in a container with 
> cpu shares set to the equivalent of 2 cpus and a quota set to 6, will end up configuring the VM for 2 CPUs rather 
> than 6.
> 
> [1] https://kubernetes.io/docs/tasks/configure-pod-container/assign-cpu-resource/#motivation-for-cpu-requests-and-limits
> 
> Bob.
> 
>