Re: TCP server app performance

On 8/12/18 9:50 AM, Honda Michio wrote:
> Hi,
> 
> I'm measuring TCP server app performance using my toy web server.
> It just accept TCP connections and responds back HTTP OK to the clients.
> It monitors sockets using kqueue, and processes each ready descriptor using
> a pair of read() and write(). (in more detail, it's
> https://github.com/micchie/netmap/tree/paste/apps/phttpd)
> 
> Using 100 persistent TCP connections (the client sends 44 B HTTP GET and
> the server responds with 151 B of HTTP OK) and a single CPU core, I only
> get 152K requests per second, which is 2.5x slower than Linux that runs the
> same app  (except that it uses epoll instead of kqueue).
> I cannot justify this by myself. Does anybody has some intuition about how
> much FreeBSD would get with such workloads?
> I tried disabling TCP delayed ack and changing interrupt rates, but no
> significant difference was observed.
> 
> I use FreeBSD-CURRENT with GENERIC-NODEBUG (git commit hash: 3015145c3aa4b).
> For hardware, the server has Xeon Silver 4110 and Intel X540 NIC (activate
> only a single queue as I test with a single CPU core). All the offloadings
> are disabled.

I hope hw L3/L4 checksumming is still on?

Are your results similar to what you get with 100 (same number as your
test clients) netperf's doing TCP_RR on this setup, or wildly different?

Regards,
Navdeep