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The other parts, schedstat and vmstat, are still quite helpful. >> Also tracepoints are more expensive than counters once enabled, I think >> that's too much for just counting numbers. > > I'm not generally a fan of eBPF, but supposedly it is really good for > stuff like this. > Yeah but not nearly as good as, for example, __schedstat_inc(var) which probably only takes a few CPU cycles if var is in the right place. eBPF is gonna take a whole bunch of sequences to even get to updating an eBPF map which itself is much more expensive than __schedstat_inc(var). For one, __migrate_swap_task() happens when dst node is fully busy (most likely src node is full as well), so the overhead of ebpf could be quite noticeable. Libo > Attaching to a tracepoint and distributing into cgroup buckets seems > like it should be a trivial script.