WF4 Performance Tip–Cache Activities

When you create a new WorkflowConsole application you will see a line of code like this

    1: WorkflowInvoker.Invoke(new Workflow1());

Looks innocent enough right? If you were only going to invoke this activity once this is not a problem.  But what if you were going to invoke this activity thousands of times? Suppose you wanted to use the activity in a WCF Service? What would the performance characteristic be?

You need to understand what happens when you create and invoke an activity. There is a great deal of one-time overhead which you could avoid by making one simple change. Here it is…

    1: private static Activity cachedActivity = new Workflow1();
    2:  
    3: private static void CacheInvoke()
    4: {
    5:     WorkflowInvoker.Invoke(cachedActivity);
    6: }
    7:  

How big of a difference does this make? Plenty… Here is a test app that uses each method 100 times.

How about 4ms vs 504ms – is that fast enough for you?

Want to know what is really going on under the covers here?  Watch this.

Comments

• Anonymous
  February 23, 2011
  Testing - wrote a comment,not sure you got it.

• Anonymous
  March 14, 2011
  Would this CacheInvoke() method be thread-safe? MSDN does not indicate that Activity instances are thread-safe.

• Anonymous
  March 15, 2011
  Yes - Remember that cachedActivity is a workflow definition (like a Type in the CLR).  And in fact the CLR caches Types for the same reason.  When you invoke it again a new instance of the activity is created and this is thread safe.