SocketsAndBockets

Welcome to part 4

If you were looking forward to some exciting new F# code this time your going to be disappointed, however if you are like me and like looking at graphs and stats and digging in deeper into the code then your going to enjoy this, lets get started…

I set up a 5 minute test with 50 clients connecting to the server with a 15ms interval between each one.  Once connected each client receives a 128 byte message from the server every 100ms so this will be a 500 messages per second test.  I am going to be using an excellent product called YourKit Profilerfor .NET it can do both memory and CPU profiling as well as displaying telemetry for things like thread count, stack contents, memory allocations etc.  It can be configured to be a lot less intrusive than a lot of other profilers and I have had a lot of success using it.  You can download a demo from their site using the link above.  I will be doing some other articles on using profiling and analysis tools later on so stay tuned for those too.  All of the graphs and information gathered in this post come from YourKits output during CPU and memory profiling.

Welcome to part three!

As promised heres a description of the inner workings.  I’m sick to death of typing SocketAsyncEventArgs so from now on I will refer to it as SAEA.

BocketPool
The BocketPool has an interesting name and with it an interesting constructor! It takes the following parameters:

number: The number of items to create in the BocketPool. size: The size of each buffer in bytes. callback: A callback function which is invoked whenever the SAEA object completes its operation.

Welcome to part two

Lets jump in at the deep end and take a look at some code…

When you look at the method syntax for the xxxAsync methods you will notice they return a boolean value that indicates if the method completed synchronously, this means that you have to check the return value every time you use one of the methods and invoke the callback yourself if it completes synchronously.  In practice this hardly ever happens, and normally only on a send operation.  But as it is a possibility we will add module with a some extension methods in to help us out, this will make the code more readable and avoid unnecessary duplication.

Welcome to part 1

A while back I read an interesting article by Brian McNamara f-async-on-the-server-side which describes C# and F# versions of a simple asynchronous socket server, one of the driving forces behind the article was how F# can wrap the traditional asynchronous model with Asynchronous Workflows, this produces nice clean simple code compared to the C# version which uses lambda expressions, the code looks quite ugly in this style!  However thats not the end of the story, a lot of memory fragmentation can occur using the APM model when there is a high throughput, so I thought I would see if I could take this a step further…