max_clients and keep alive

[Tristan Griffiths]

Hello,

Trying to better understand the worker_processes and worker_connections
settings.

We have always run Nginx with worker_processes 4 and worker_connections
1024 on a dual Xeon 2.4GHz with Hyper Threading. In the documentation,
it suggests it is better to run worker_processes 2 and
worker_cpu_affinity 0101 1010 for a dual HTT machine but according to
the formula (max_clients = worker_processes * worker_connections) that
would effectively halve the connections we can support to clients and
backend servers.

We regularly see more than 2000 keep alive connections at any point in
time, so do keep alive connections count towards the maximum client
connections?

Thanks,

Tristan