On Sat, Mar 05, 2022 at 09:44:27AM -0700, dann frazier wrote: > The LTP cpuset_sched_domains test, authored by Miao Xie, fails on a Kunpeng920 > server that has 4 NUMA nodes: > https://launchpad.net/bugs/1951289 > > This does appear to be a real bug. /proc/schedstat displays 4 domain levels for > CPUs on 2 of the nodes, but only 3 levels for the others 2 (see below). > I assume this means the scheduler is making suboptimal decisions about > where to place/move processes. I'm not sure how to demonstrate that - but > open to suggestions if that evidence is important justification for stable. > > This is not a problem in current upstream kernels, so I bisected and found > that the first patch here fixes it. I can't tell from the commit message > if fixing this case was Valentin's intent, or just a happy side-effect of the > set conversion. The other two patches fix regressions introduced by the first. > All cherry-pick cleanly back to 5.10.y and 5.4.y. This platform easily > reproduces the problem Dietmar's fix addresses. I don't have hardware to test > the ia64 fix. > > Note: This also impacts earlier stable trees, but require some minor porting, > so I'll submit fixes for those separately. > > Here's a comparison of /proc/schedstat before & after applying these > fixes: Thanks, now queued up. greg k-h
