Profiling Traces

[David Chisnall]

Hello all of the GNUstep developers,

We've recently been working on a tool called TESLA that allows you to write 
temporal assertions (e.g. before you get here, this other function must have 
been called and returned this value) that are checked at run time, but also 
provides a convenient way of adding instrumentation to programs.

I've uploaded a couple of profiling traces to give people an idea of the kinds 
of thing this can generate:

http://theravensnest.org/Drawing.log
http://theravensnest.org/NSCursor.log

The first is a log of all of the drawing messages in the protocol defined by 
NSGraphicsContext (i.e. the thing used to communicate between -gui and -back), 
indented based on the current view and cell that is responsible for the 
drawing.  This doesn't provide a full stack trace, just some context.  The 
motivation for this is Ivan's work on the Opal back end, and looking at exactly 
how the back end is used.  Are we doing too many pushes and pops of graphics 
state, or saving and restoring when we don't need to?  Are we calling methods a 
lot that are poorly optimised in the back end?

The second is a stack trace, generated in every place where we call a push or 
pop method.  The motivation for this was the recent work trying to find bugs in 
the NSCursor balancing code.  Unfortunately, I wasn't able to reproduce the 
bugs when I tried (maybe they're all fixed?) and so this isn't very useful, 
although it might be interesting.

Can anyone else think of other useful traces that we might want to generate?

David

-- Sent from my Apple II