Simulate a NUMA arch

[svalat]

I need to enter again in the sources to check it is really possible, but it might be interesting to offer the possibility to simulation a NUMA topology while making a local run (for example on our laptop/workstation) without a real NUMA arch.

As most of the NUMA binding tracking is based on first touch policy, it might be possible to simulate for most of the accessed. There might be some places where it might not be possible to check.

One of the intereseting think can be to get a feeback on our NUMA support while making a very small run and not requiring to make a large one where the numaprof cost can be very high.

I seen this issue while passing on one weather simulation.

[svalat]

En théorie cela doit marcher en calculant un binding fictif des threads. Ce n'est par parfait mais peut dejà permettre d'avoir une vue "théorique" de ce qui peut être attendu.

[svalat]

Can work in principle, we need to provide the list of core->numaId to emulate.

Sometime numaprof look on the OS numa pages so we might want to signal if a page is the decision of the OS so we do not know. It can be another category than "unpinned". Or we can simply mark them as unpinned which might be fine for a first look.