On Wed, 11 Mar 2015 16:36:43 +0000 Ian Malone ibmalone@gmail.com wrote:
Since I can't reproduce this problem I'm not sure what's causing it. If you really are finding make subprocesses limited to 100% cpu across the lot then maybe have a look to see if there are any cgroups limits active https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/htm... may also be worth running on the stock fedora kernel to test that it's not something that you've turned on in your custom kernel.
I looked in the kernel documentation, and it seems that in order to be limited by cgroups, the application has to create a cgroup and attach to it. The cgroups are in a virtual file system under /sys/fs. They can be seen by cat /etc/mtab The one of interest in the case of compiling is the cpu,cpuset. The kernel makefiles don't create or attach to a cgroup, so that would seem to eliminate it as a consideration.
There is also a systemd target for cgroups, but it is supposed to be only for services, which compiling wouldn't be.
And, there is also a selinux target for cgroups, but it doesn't seem to apply here.
So, cgroups seem like another dead end.