[IronPython] Bad performance calling .NET method

[Dino Viehland]

I assume something is going horribly wrong with our type checks.   Can you attach the repro?  Or at least are these just classes, or are any structs, or maybe weird classes like delegates?

And is this on .NET 2.0 or .NET 4.0?

From: users-bounces at lists.ironpython.com [mailto:users-bounces at lists.ironpython.com] On Behalf Of Laurion Burchall
Sent: Tuesday, April 20, 2010 2:11 AM
To: Discussion of IronPython
Subject: [IronPython] Bad performance calling .NET method

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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