What is the real overhead of try/catch in C#?

c# .net performance optimization try-catch
JC Grubbs picture JC Grubbs · Sep 9, 2008 · Viewed 24.1k times · Source

So, I know that try/catch does add some overhead and therefore isn't a good way of controlling process flow, but where does this overhead come from and what is it's actual impact?

Answer

Shaun Austin picture Shaun Austin · Sep 9, 2008

Three points to make here:

  • Firstly, there is little or NO performance penalty in actually having try-catch blocks in your code. This should not be a consideration when trying to avoid having them in your application. The performance hit only comes into play when an exception is thrown.

  • When an exception is thrown in addition to the stack unwinding operations etc that take place which others have mentioned you should be aware that a whole bunch of runtime/reflection related stuff happens in order to populate the members of the exception class such as the stack trace object and the various type members etc.

  • I believe that this is one of the reasons why the general advice if you are going to rethrow the exception is to just throw; rather than throw the exception again or construct a new one as in those cases all of that stack information is regathered whereas in the simple throw it is all preserved.

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