On 2021/04/05 09:34, Scott Cheloha wrote: > > On Apr 5, 2021, at 09:07, Stuart Henderson <s...@spacehopper.org> wrote: > > > > I've attached r620-E5_2630v2-2p6c2t.tgz, from Dell PE R620 with E5-2630v2. > > This is a machine which has "disabling user TSC (skew=XXX)" reported for > > some cores: > > > > Nov 5 16:08:34 pweb /bsd: cpu11: disabling user TSC (skew=-107) > > Nov 5 16:08:34 pweb /bsd: cpu13: disabling user TSC (skew=-101) > > This is probably NUMA latency when synchronizing between packages.
Interesting, just updated a dual socket R610 (Intel(R) Xeon(R) CPU L5520 @ 2.27GHz, 2394.39 MHz, 06-1a-05, smt 0/1, core 0-3, package 0/1) to 6.9 and remembered about this. In that case there's no "disabling user TSC". Production server so not a good one for running debug kernels etc..but thought it was worth drafting a quick mail to mention that it's not all NUMA machines.
