By default, the 5-tuple is used to load balance flows. Exporters with
many flows are bound to a specific worker. Use eBPF to do a per-packet
load-balancing.
Currently, this is done randomly, but we will use a percpu counter in
the next commit. This will make the test easier too, maybe?
This should also enable graceful restart but not with the current
Docker Compose setup, we would need to use mode host or spawn a new one
in the same network namespace than the old one. This does not look like
very complex:
- spawn a new inlet in the same network namespace, but listening to a
different HTTP port
- stop the previous inlet
- spawn a new inlet in the same network namespace
- stop the previous inlet
Alternatively, we could use SO_REUSEPORT for the HTTP socket too!
If the kernel is too old for timestamping, it should not be fatal. I
prefer to not accept SO_TIMESTAMP_OLD as the size of the timestamp is
arch-dependent.
Fix#1978
With very large receive buffer, we may process many packets in burst
and not account for the real receive time. The kernel is able to
provide us with a timestamp, use it. We ask for hardware timestamps if
possible.
