[IronPython] Bad performance calling .NET method

[Laurion Burchall]

I am getting terrible performance invoking a C# method from IP. I have a static class called Api with this method:

  public static void MakeKey(JET_SESID sesid, JET_TABLEID tableid, string data, Encoding encoding, MakeKeyGrbit grbit)

When I call it directly from C# I get about 3M calls/second. In IronPython I get only 50,000 calls/second -- a 60X slowdown!

The method is overloaded. When I call these overloads I get good performance (~ 1M calls/second):
  public static void MakeKey(JET_SESID sesid, JET_TABLEID tableid, int data, MakeKeyGrbit grbit)
  public static void MakeKey(JET_SESID sesid, JET_TABLEID tableid, float data, MakeKeyGrbit grbit)
  public static void MakeKey(JET_SESID sesid, JET_TABLEID tableid, byte[] data, MakeKeyGrbit grbit)
(for the last overload I passed in the string turned into a byte array with Encoding.GetBytes())

Things I have tried that didn't help:
 - Changing the name of the method so it was unique.
 - Calling the method using Api.MakeKey.Overloads[...]
 - Calling other methods I have that take string arguments. They were fast.

When I profile the code the time shows up in mscorwks.dll (56%) and mscorlib.ni.dll (17%). IronPython is only 8% and my code is 6%.

Can anyone help me work out what is going wrong? I have a short, turn-key repro of this. MakeKey is a very commonly used method so having it be so slow is crippling.

thanks,
--Laurion


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