LTTng

On the reason for having one shm file per cpu (per channel/per uid/per session): having one file per cpu is mainly done to facilitate NUMA-local memory allocation. That being said, I wonder if as a future improvement we could combine all per-cpu buffers into a single shm file, and issue numa_set_preferred piecewise when mmapping regions of the files. This would lessen the number of file descriptors needed by a significant amount. I suspect it would work, but we'd need to do some prototyping to validate this approach first.