Re: apache parked processes using CPU

[RVP <rvp%SDF.ORG@localhost>]

On Sun, 13 Nov 2022, Jan Schaumann wrote:

> 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]
> [...]
> Anybody have any ideas how to pinpoint what caused
> this?

If the timeout given to _lwp_park() (or whatever that calls it here) is
too short, then the threads will just repeatedly re-enter the kernel with
another syscall.

Attach GDB to one of the httpd processes and check what the
timespec/timeval values are.

-RVP