Tuning nginx on EC2

[Chetan Sarva]

Hi,

I've been doing some benchmarks with nginx on EC2 and have run into a
bit of a wall. I'm trying to establish a baseline from which to
compare my application against. For this I'm using the simplest
possible nginx config:

server {
        listen  80;
        access_log off;
        return 204;
}

With a large instance (1gbps nic), I've only been able to get up to
about 12k reqs/sec despite the fact that all resources
(cpu/mem/disk/network) appear to be under-utilized. My base platform
is Ubuntu 10.04 with nginx 0.8.53. I've tried generating load from
multiple nodes using a variety of tools, but still can't seem to push
passed 12k. Perhaps there's just some limit within EC2 that I'm
unaware of.

I've tried tweaking lots of sysctl settings to no end, but it could be
I just haven't found the correct one yet. Has anyone had any luck
getting higher throughputs on ec2?

regards,

chetan