Re: [hwloc-users] Question about hwloc_bitmap_singlify

2018-08-28 Thread Brice Goglin
Hello If you bind a thread to a newset that contains 4 PUs (4 bits), the operating system scheduler is free to run that thread on any of these PUs. It means it may run on it on one PU, then migrate it to the other PU, then migrate it back, etc. If these PUs do not share all caches, you will see a

[hwloc-users] Question about hwloc_bitmap_singlify

2018-08-28 Thread Junchao Zhang
Hi, On cpu binding, hwloc manual says "It is often useful to call hwloc_bitmap_singlify() first so that a single CPU remains in the set. This way, the process will not even migrate between different CPUs inside the given set" . I don't understand it. If I do not do hwloc_bitmap_singlify, what