[DISCUSSION] Is Squeak/Smalltalk able to do this?

Stephane Ducasse ducasse at iam.unibe.ch
Sat Feb 8 16:15:38 UTC 2003

You have also MethodWrappers from john Brant (I know somebody ported 
them to squeak).
You can also read my Joop paper: message passing Control in Smalltalk 
available on my webpage.

On Saturday, February 8, 2003, at 03:41 PM, John W. Sarkela wrote:

> Sure, though the major caveat is that observation changes things.
> The easiest was would be to intercept the message send itself
> with a method wrapper. As long as the observation mechanism
> doesn't get introspective, Heisenbubbles won't be a problem.
> Further, the overhead of the wrapper/intercept mechanism is
> deterministic and can be calibrated out of the statistics.
> David Caster implemented such an intercept mechanism for
> a basic instrumentation framework, I'll see if I can get him to
> package this up for Squeak map. Basically, you attach probes
> to a set of methods (specified by class and selector). These
> probes are attached to an instrument that can capture receiver
> and args on the way into the method and return value upon
> exit, and do with them what they will. The basic advantages
> to this approach is that the code under test has no textual
> changes to support observation, nor is the method recompiled.
> Further, the implementation has a low overhead that may be calibrated.
> I suspect that you would be very interested to read the papers
> that Urs Hölze wrote on adaptive optimization based
> on his hotspot compiler work, first for Self and subsequently
> for Smalltalk and Java.
> :-}> John Sarkela
> On Friday, February 7, 2003, at 07:59 PM, Doug Clapp wrote:
>> Given that Squeak is "reflective," would it be possible
>> to write code such that...
>> -- the system was "watched" as it was exercised, and...
>> -- attention was paid to which "cases"  (ifTrue/ifFalse)
>> were triggered more often, and...
>> -- the methods were then re-written to have the "most
>> likely (often)"if" be placed first in the method, to speed
>> up the execution of "most often done things"?
>> Obviously, this idea could be taken much further...
>> doug clapp
Prof. Dr. Stéphane DUCASSE (ducasse at iam.unibe.ch) 
  "if you knew today was your last day on earth, what would you do
  different? ... especially if, by doing something different, today
  might not be your last day on earth" Calvin&Hobbes

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