apache parked processes using CPU

[Jan Schaumann <jschauma%netmeister.org@localhost>]

Hey,

About two days ago, my apache-2.4.54 running on my
NetBSD-9.3 amd64 VPS started leaving multiple
processes in 'parked' state, utilizing a lot of CPU:

  PID USERNAME PRI NICE   SIZE   RES STATE      TIME WCPU    CPU COMMAND
21048 nobody    42    0   316M   14M parked     5:28 7.32%  7.32% httpd
17677 nobody    42    0   318M   14M parked     5:25 6.69%  6.69% httpd
16398 nobody    41    0   319M   17M parked    18:53 5.03%  5.03% httpd
  829 nobody    41    0   320M   18M parked    18:59 4.83%  4.83% httpd
21512 nobody    42    0   322M   19M parked    18:49 4.74%  4.74% httpd
23308 nobody    42    0   322M   19M parked    18:51 1.61%  1.61% httpd
    0 root     125    0     0K   20M vdrain    11:44 0.00%  0.00% [system]

This is new behavior that began without my having made
any changes to the system on which httpd has been
running for years without such problems.

I don't see any obviously different traffic patterns
from before, either, so I'm quite confused as to what
may have triggered this change.

Anybody have any ideas how to pinpoint what caused
this?

-Jan