(+Cc relevant folks)
Hi,
On 21/01/21 15:41, Meelis Roos wrote:
> This happens on Sun Fire X4600 M2 - 32 cores in 8 CPU slots. 5.10 was silent.
> Current git and
> 5.10.0-13256-g5814bc2d4cc2 exhibit this message in dmesg but otherwise seem
> to work fine
> (kernel compilation succeeds).
>
b5b217346de8 ("sched/topology: Warn when NUMA diameter > 2") was added in
5.11-rc1, and I believe was marked for stable.
It doesn't come with a scheduler behaviour change, it only catches
topologies that end up being silently (unless run with SCHED_DEBUG=y)
misrepresented / misinterpreted by the scheduler.
Up until now I had only seen it fire on a single, somewhat unusual
topology. As fixing it is far from trivial, I figured adding this warning
would let us build a case for actually fixing it if we get some more
reports.
Could you paste the output of the below?
$ cat /sys/devices/system/node/node*/distance
Additionally, booting your system with CONFIG_SCHED_DEBUG=y and
appending 'sched_debug' to your cmdline should yield some extra data.
