Strange issue when running application on 64 bits in C# .NET

Question

All,

I have a server application which reads messages off a queue and writes them in a database by calling stored procedures. It is written in C# targetting .NET Framework 3.5 The server is XEON 2.4Ghz (16 cores)

In my Build properties I had the Platform Target as "Any CPU". The result was in the server, all cores to run constant at 100% but the application was running slow ! I changed the Platform Target to be x86 and when running on the server is running much faster than before and the Cores are around 20-30% load.

I can't really explain what is happening.

Any ideas?

Thanks,

MK

Answer 1

This blog post by the MS guy Rick Byers talks about just this: AnyCPU Exes are usually more trouble than they're worth

A quote from the blog is: 32-bit tends to be faster anyway which could be a part of the answer.

Edit: Added a bit of my answer that I forgot as Hans Passant pointed out.

Answer 2

Well, doesn't make a lot of sense. But you are running with a very different dbase provider. The 64-bit versions of them are relatively new and might not have gone through the same kind of rigorous testing and optimization as their 32-bit versions.

Still, a program like this should always block on the queue read and the dbase write. I/O is always slow, much slower than raw code. Only when the thread blocks on an I/O request will it use less than 100% of the CPU cycles.

Do make sure that it isn't throwing and catching exceptions frequently. That's expensive and easily gobbles up all CPU resources. Visible while debugging in the Output window.