Performance issue with large interfaces

[rauhs]

Hi,

this is basically #1128. Not sure how to re-open it.

Though, it's making Moq unusable for some tests. For us, we have a interface with over 500 slots (GetInterfaceMap) which is taking all the time.

Here is a quick PerfView trace of the runtime:

Name                                                                                                                                                    	Inc %	      Inc	Exc %	Exc	Fold	                             When	      First	       Last
 castle.core!Castle.DynamicProxy.AbstractInvocation.Proceed()                                                                                           	 98.7	   13,601	  0.0	  0	   0	 09999999999999999999999999999999	 10,774.284	 24,810.652
+ moq!Moq.CastleProxyFactory+Interceptor.Intercept(class Castle.DynamicProxy.IInvocation)                                                               	 98.7	   13,601	  0.0	  1	   0	 99999o99999999999999999999999999	 10,774.284	 24,810.652
 + moq!Moq.Mock.Moq.IInterceptor.Intercept(class Moq.Invocation)                                                                                        	 98.7	   13,597	  0.0	  0	   0	 99999o99999999999999999999999999	 10,774.284	 24,810.652
 |+ moq!FindAndExecuteMatchingSetup.Handle                                                                                                              	 98.7	   13,594	  0.0	  1	   0	 o9999999999999999999999999999999	 10,774.284	 24,810.652
 ||+ moq!SetupCollection.FindLast                                                                                                                       	 98.6	   13,585	  0.0	  0	   0	 o9999999999999999999999999999999	 10,774.284	 24,810.652
 |||+ moq!Moq.Setup.Matches(class Moq.Invocation)                                                                                                       	 98.6	   13,585	  0.0	  0	   0	 o9999999999999999999999999999999	 10,774.284	 24,810.652
 ||| + moq!Moq.MethodExpectation.IsMatch(class Moq.Invocation)                                                                                          	 98.6	   13,584	  0.0	  0	   0	 o9999999999999999999999999999999	 10,774.284	 24,810.652
 ||| |+ moq!Moq.MethodExpectation.IsOverride(class Moq.Invocation)                                                                                      	 98.6	   13,583	  0.0	  0	   0	 o9999999999999999999999999999999	 10,774.284	 24,810.652
 ||| ||+ moq!Moq.Invocation.get_MethodImplementation()                                                                                                  	 97.1	   13,387	  0.0	  0	   0	 o9899999999989999898999989999999	 10,776.284	 24,810.652
 ||| |||+ moq!Extensions.GetImplementingMethod                                                                                                          	 97.1	   13,387	  0.0	  0	   0	 o9899999999989999898999989999999	 10,776.284	 24,810.652
 ||| ||| + mscorlib.ni!RuntimeType.GetInterfaceMap                                                                                                      	 97.0	   13,368	  0.1	 15	   0	 o9899999999989899898999989999999	 10,776.284	 24,810.652
 ||| ||| |+ mscorlib.ni!RuntimeType.GetMethodBase                                                                                                       	 49.2	    6,773	  0.3	 35	   0	 o5444554444444454444444545445454	 10,776.284	 24,810.652
 ||| ||| |+ mscorlib.ni!DomainNeutralILStubClass.IL_STUB_PInvoke(System.RuntimeTypeHandle, System.RuntimeTypeHandle, System.RuntimeMethodHandleInternal)	 44.8	    6,177	  0.2	 27	   0	 o4444444434444344444443434444344	 10,787.290	 24,808.652
Name

The fix is pretty simple:

// Moq.Extensions:
		private static readonly ConcurrentDictionary<Tuple<Type, Type>, InterfaceMapping> mappingsCache = new ();

		private static InterfaceMapping GetInterfaceMap(Type type, Type interfaceType)
		{
			return mappingsCache.GetOrAdd(Tuple.Create(type, interfaceType), tuple => tuple.Item1.GetInterfaceMap(tuple.Item2));
		}

This makes the above run in a few ms as opposed to 14 seconds.

[stakx]

Thanks for posting a possible solution. Before we apply it, could we look at a test case that demonstrates the problem? Could you post a minimally complete repro code example?

[rauhs]

@stakx Reproducer is at:

https://gist.github.com/rauhs/4cbe672e26dd6727e84f7b96c68dcf1f

Without optimization: 24seconds

With opt: 7ms.

(even with "only" 50 properties we're at 1s of runtime vs 5ms, so huge performance penalty even for non-gigantic interfaces)

[rauhs]

Is there anything we can do to expedite this?

[aleksandr-grechko]

@kzu Could you release new version of Moq with this fix? It would allow us to significantly decrease time of unit tests execution for our project.

[kzu]

Done! https://github.com/devlooped/moq/releases/tag/v4.20.70