Re: pgdaemon high CPU consumption

[Frank Kardel <kardel%netbsd.org@localhost>]

Hi Matthias !

See PR 55707 
http://gnats.netbsd.org/cgi-bin/query-pr-single.pl?number=55707 , which 
I do not considere fixed due to the pgdaemon issue. reverting arc.cto 
1.20 will give you many xcalls, but the system stays more usable.

Frank


On 07/01/22 07:55, Matthias Petermann wrote:
> Good day,
>
> since some time I noticed that on several of my systems with 
> NetBSD/amd64 9.99.97/98 after longer usage the kernel process pgdaemon 
> completely claims a CPU core for itself, i.e. constantly consumes 100%.
> The affected systems do not have a shortage of RAM and the problem 
> does not disappear even if all workloads are stopped, and thus no RAM 
> is actually used by application processes.
>
> I noticed this especially in connection with accesses to the ZFS set 
> up on the respective machines - for example after checkout from the 
> local CVS relic hosted on ZFS.
>
> Is there already a known problem or what information would have to be 
> collected to get to the bottom of this?
>
> I currently have such a case online, so I would be happy to pull 
> diagnostic information this evening/afternoon. At the moment all info 
> I have is from top.
>
> Normal view:
>
> ```
>   PID USERNAME PRI NICE   SIZE   RES STATE       TIME   WCPU CPU COMMAND
>     0 root     126    0     0K   34M CPU/0     102:45   100% 100% 
> [system]
> ```
>
> Thread view:
>
>
> ```
>   PID   LID USERNAME PRI STATE       TIME   WCPU    CPU NAME COMMAND
>     0   173 root     126 CPU/1      96:57 98.93% 98.93% pgdaemon [system]
> ```
>
> Kind regards
> Matthias