[racket] current backtrace implications of JIT

From: Neil Van Dyke (neil at neilvandyke.org)
Date: Sun Jun 27 23:07:16 EDT 2010

What effect does the JIT currently have on debugging backtraces?  Or, 
how can one get some or all of the benefit of the JIT, but still 
reliably get useful backtraces?

I see that DrScheme now has an option for disabling some JIT 
optimizations.  Should I just do whatever that checkbox is doing?

Details on my particular system... A while ago, I had to disable the JIT 
for a large system so that we could reliably get useful backtraces at 
the time (i.e., not just our top-level entry point).  After some 
performance testing with PLT 4.2.5 just now, I'm seeing the JIT give 
performance gains of over 19x for some functions (at least, in contrived 
tests with huge numbers of iterations).  So, we would *really* like to 
be using the JIT, so long as we can keep our backtraces.  We have a 
custom error escape handler, if that matters.


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