| Re: [mosquitto-dev] CPU use and message count high, but no message to be found |
Wiebe Cazemier <wiebe@xxxxxxxxxxxx> wrote:
> Hi,
>
> I have a Mosquitto 1.6 server (with EPOLL) with about 9100
> connections that is using about 10-20% CPU.
> '$SYS/broker/load/messages/received/1min' and
> '$SYS/broker/load/messages/sent/1min' are also about 9100, but
> when I subscribe to '#' (which my custom auth plugin written in
> c++ supports for my user), I see only about 2 messages per
> minute: the ones of normal operation.
>
> I seem to remember that even having thousands of connections,
> the CPU use was mostly 1%-2%, or 5% or so. But I don't remember
> if the message stats was low before; if the 9100 is new/wrong.
>
> Before I restart it to see what happens, I'd like to ask if
> this is normal, and what I can do to get some more debugging
> info.
>
> Does each connection require one message per minute?
Depends what your keepalive is. If I read my octal correctly,
it's 300/320 pairs, which corresponds to pingreq/pingresp
packets, which would make sense.
I have no opinion or input on the cpu usage, but this would
appear to be messages counted from pings.
Sincerely,
Karl Palsson
>
> More debugging output below
>
> Regards,
>
> Wiebe
>
>
>
> PS: output of '$SYS/#':
>
> $SYS/broker/uptime 3740677 seconds
> $SYS/broker/clients/total 9155
> $SYS/broker/clients/inactive 0
> $SYS/broker/clients/disconnected 0
> $SYS/broker/clients/active 9155
> $SYS/broker/clients/connected 9155
> $SYS/broker/load/messages/received/1min 9268.31
> $SYS/broker/load/messages/received/5min 9214.63
> $SYS/broker/load/messages/received/15min 9197.42
> $SYS/broker/load/messages/sent/1min 9275.12
> $SYS/broker/load/messages/sent/5min 9233.16
> $SYS/broker/load/messages/sent/15min 9217.21
> $SYS/broker/load/publish/received/1min 15.46
> $SYS/broker/load/publish/received/5min 20.41
> $SYS/broker/load/publish/received/15min 19.66
> $SYS/broker/load/publish/sent/1min 20.68
> $SYS/broker/load/publish/sent/5min 34.47
> $SYS/broker/load/publish/sent/15min 34.52
> $SYS/broker/load/bytes/received/1min 27762.11
> $SYS/broker/load/bytes/received/5min 30675.57
> $SYS/broker/load/bytes/received/15min 30740.83
> $SYS/broker/load/bytes/sent/1min 22258.72
> $SYS/broker/load/bytes/sent/5min 26942.58
> $SYS/broker/load/bytes/sent/15min 27360.02
> $SYS/broker/load/sockets/1min 41.52
> $SYS/broker/load/sockets/5min 42.62
> $SYS/broker/load/sockets/15min 41.94
> $SYS/broker/load/connections/1min 38.04
> $SYS/broker/load/connections/5min 39.80
> $SYS/broker/load/connections/15min 39.18
> $SYS/broker/messages/received 536248480
> $SYS/broker/messages/sent 536396243
> $SYS/broker/subscriptions/count 9145
> $SYS/broker/heap/current 18446744073651706464
> $SYS/broker/publish/messages/received 877757
> $SYS/broker/publish/messages/sent 705530
> $SYS/broker/publish/bytes/received 264372253
> $SYS/broker/publish/bytes/sent 263511454
> $SYS/broker/bytes/received 1670467528
> $SYS/broker/bytes/sent 1366423873
>
> Strace on the PID shows a lot of:
>
> rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
> read(7473, "\300", 1) = 1
> read(7473, "\0", 1) = 1
> write(7473, "\320\0", 2) = 2
> rt_sigprocmask(SIG_SETMASK, [HUP INT USR1 USR2 TERM], [], 8) =
> 0 epoll_wait(14, [{EPOLLIN, {u32=7746, u64=7746}}], 1000, 100)
> = 1 rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0 read(7746,
> "\300", 1) = 1 read(7746, "\0", 1) = 1 write(7746, "\320\0", 2)
> = 2 rt_sigprocmask(SIG_SETMASK, [HUP INT USR1 USR2 TERM], [],
> 8) = 0 epoll_wait(14, [{EPOLLIN, {u32=1456, u64=1456}}], 1000,
> 100) = 1 rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
> read(1456, "\300", 1) = 1 read(1456, "\0", 1) = 1 write(1456,
> "\320\0", 2) = 2
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