On Mon, Jul 31, 2017 at 03:28:47PM -0400, Rik van Riel wrote: > From: Rik van Riel <r...@redhat.com> > > Running 80 tasks in the same group, or as threads of the same process, > results in the memory getting scanned 80x as fast as it would be if a > single task was using the memory. > > This really hurts some workloads. >
It would be nice to specify what workloads in particular and what sort of machine because I'm willing to bet it has a bigger impact on machines with 4+ nodes, particularly if they are not fully connected topologies. Furthermore, I'm willing to bet that there would be small regressions on 2-socket machines but with less time spent scanning and processing faults even if remote accesses are marginally increased. Still, on balance, this is preferred behaviour. > Scale the scan period by the number of tasks in the numa group, and > the shared / private ratio, so the average rate at which memory in > the group is scanned corresponds roughly to the rate at which a single > task would scan its memory. > > Signed-off-by: Rik van Riel <r...@redhat.com> Acked-by: Mel Gorman <mgor...@suse.de> -- Mel Gorman SUSE Labs
