[erlang-questions] 20k messages in 4s but want to go faster!

Florian Weimer fw@REDACTED
Sun Jul 12 11:28:35 CEST 2009

* Joel Reymont:

> Yes, these are EC2 figures. Can you elaborate on how
> IO is a problem on virtual processors?

You're sending 20K messages, which requires 40K interrupts and
hypervisor/kernel transitions when naively implemented (one for the
message, one for the ACK from the client), and 20K userland/kernel
transitions.  This is not necessarily an area where virtualization
solutions shine.

You need to ask the EC2 folks if this is a problem for them (interrupt
mitigation can increase throughput, so the 40K number is not hard
bound), and what can be done about it.  Perhaps they offer some sort
of TCP termination service which takes care of these details.

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