high CPU usage on Synapse

[dima]

Good day and a happy new year,

we are facing a issue with cloudron performance and find out the reason with Matrix/Synapse.
Without interruption it shows:
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
149 cloudron 20 0 3276808 312768 19816 S 96.7 1.9 6123:36 python3
restart, more memory - nothing helps.

Anybody out there with a hint,what we can ceck and fix?

kind regards
dirk

[girish]

Anything in the logs? But I think it's document somewhere upstream that with lots of federation, memory usage and CPU will be high.

[girish]

See https://github.com/element-hq/synapse/blob/master/docs/usage/administration/admin_faq.md?plain=1#L223

[dima]

Hi,
in logs I can find nothing, federation is off.
I had a look at the website and add to homeserver.yaml:
caches:
global_factor: 2.0
per_cache_factors:
get_users_who_share_room_with_user: 2.0
sync_response_cache_duration: 4m
cache_autotuning:
max_cache_memory_usage: 4096M
target_cache_memory_usage: 1516M
min_cache_ttl: 30m

Then I deleted approx. 400 unused rooms, but nothing helps.
I guess it is related to presence. There are 186 users, not too much.

Maybe we move Matrix/Element to separate hardware.

greetings
dirk