Low number of running actions when building in a windows docker container

[Luc Bertrand]

Hi everyone,

I'm struggling with Bazel running in a Windows Docker Container.

When running bazel build I get 16 actions, but only 1 or 2 maximum are running in parallel. The others are [Sched].

I checked the number of cpu visible by the container and I get: 

wmic cpu get /Format.List

...

NumberOfCores=8

NumberOfEnabledCores=8

NumberOfLogicalProcessor=16

...

ThreadCount=2

The windows container sees 16 logical cores (8 physical cores).  but only 2 Threads (when it's 16 on the host), I guess that could be the reason.

But then I tried to check in bazel codebase how it detects the number of cpus, and it seems that it uses Runtime.getRuntime().availableProcessors() from java.

And according to a small Main.java I wrote, Runtime.getRuntime().availableProcessors()  returns 16 in my docker instance.Hence I don't understand why I'm still stuck with 2 actions running in parallel ....

Any ideas ?

Thanks !