Unable to get rspamd to use all of my cpu(s)

[Marco Pizzoli]

Hi all,

I am using rspamd only for DKIM-signing outgoing email.

Yes, it is fast but not as fast as I think I could achieve.

I am using Postfix 3.2, rspamd 1.6.2 and the integration via rspamd-proxy, via TCP
The rspamd process is reaching only 30 / 35% of my cpu.

It *is* fast, I could manage to get 100K emails delivered in a hour, but I think it could be even faster by leveraging all the available cpu.

My thought is that due to the way the milter protocol works (every iteration between the MUA and Postfix has a corresponding iteration between Postfix and rspamd-proxy) the entire flow is slowed down.

I tried to increase the number of rspamd-proxy processes and the only result I achieved was to distribute the "35%" load between all the rspamd-proxy processes. So, 12% one, 7% another one, etc...

So I ask you, if I wanted to maximize the rspamd throughput what should I do?

Duplicating my Postfix smtpd so to have two daemons milter-asking to rspamd would be a good solution?

Thank you in advance

Marco