IKS: No physical topology data is available

[Paweł Moll]

Background: A profiling tool wants to present comprehensive information about the system. This includes list of all (physical) cores available in the system.

Situation: Let's assume the IKS system boots on the big cluster and (for whatever reason) stays on it forever, as in: never switches to the little one.

Problem: The tool (either in the userspace or in kernel) has no means of obtaining information about the other cores, in particular about their type.

Example: A15x2/A7x2 system. Boots on A15 and stays like this forever. The profiling tool knows that there are 4 cores in the system, knows that 2 currently active ones are A15, but has no way of knowing that the other two are A7s.

Solution: Provide topology data information, either as kernel API (enumerate all available cores and their cpuids) or in userspace (/proc/cpuinfo equivalent?).