Learning DCOM

Performance Results for ThreadingModel=“”

This section captures the performance results when the ThreadingModel of CLSID_Details is ThreadingModel="". Remember that a COM class within an in-process server must specify its threading semantics using the ThreadingModel registry named value. If this named value is missing for a given in-process COM class, ThreadingModel="" is assumed. This means that an instance of this COM class will always be activated inside the main STA.

To make the discussion easier, concentrate on the VoidCall column in each table shown below. Note the following:

• In all rows shown in Table B-1 through Table B-3, the client apartment is different from the server apartment. This implies that marshaling will result.

• For all in-process method invocations (the rows labeled “In-process”), the client apartment marshals interface pointers between itself and a different apartment, the main STA.

• In-process and local out-of-process method invocations are essentially equivalent when the client and server exist in different apartments.

• A remote method invocation is about 16 to 18 times more expensive than an in-process or a local out-of-process method invocation.

• The results for MTAThread1 and MTAThread2 should be very similar, because both of these threads live in the one and only MTA within the client process.

Table B-1. Client Apartment: STA (Secondary STA Thread)

	FirstCall	VoidCall	ArrayCall	LongCall
In-process	0.000134	0.000126	0.000131	0.001157
Local	0.000780	0.000173	0.000182	0.001608 ...