Java TCP/IP Socket write performance optimization

Question

Server Environment

Linux/RedHat
6 cores
Java 7/8

About application :

We are working on developing a low latency (7-8 ms) high speed trading platform using Java. Multi-leg orders are sent after algo conditions are met

Problem

The orders to the exchange using TCP/IP java.net.Socket APIs (using java.io.OutputStream.write(bytes[] arg0) ). Profiler measurement is records as 5-7 microsec which is very high as per our low latency reqs. We are not made use of setPerformancePreferences() api as suggested in one of the questions posted in stacktrace.

Question

1. Any alternatives to java.net.Socket to reduce the socket transmission time?
2. Any optimization techniques to improve performance
3. Is setPerformancePreferences() is of any use?

Answer 1

We are not made use of setPerformancePreferences() api

It doesn't do anything and never has. I wouldn't worry about it.

Any alternatives to java.net.Socket to reduce the socket transmission time?

The problem is most certainly not a software one. You can get <8 micro-seconds from Java to Java on different machines, but you need low latency network cards like Solarflare or Mellanox.

If you want fast processing you should consider either a high GHz haswell processor, possibly over clocked to 4.2 or 4.5 GHz or a dual socket Haswell Xeon. The cost of these compared to the cost of trading is not high.

Any optimization techniques to improve performance

Using non-blocking NIO i.e. ByteBuffers and busy waiting on the socket connections. (I wouldn't use Selectors as they add quite a bit of overhead) I would turn off nagle.

For some micro-tuning, use an affinity bound thread on an isolated cpu.

Is setPerformancePreferences() is of any use?

Looking at the source .. I will let you be the judge.

public void setPerformancePreferences(int connectionTime,
                                      int latency,
                                      int bandwidth)
{
    /* Not implemented yet */
}

Java 7/8

In term of which version to use, I would start with Java 8 as it has much improved escape analysis which can reduce garbage of short lived objects and thus help reduce latency between GCs and jitter from GCs.