Re: [Help-smalltalk] PATCH0/2: byte code profiling for gst

[Derek Zhou]

On Sunday 08 February 2009 12:02:39 pm Derek Zhou wrote:
> These patches add profiling support to gst. 
> Usage:
> 
> Smalltalk profileOn.
> ... [ the code you want to profile ]
> Smalltalk profileOff.
> CallGraph new printCallGraphToFile: 'profile.out'.
> 
> Which will generate a callgrind compatible profile 'profile.out' which can be 
> viewed by kcachegrind. 

A few known caveats:
* byte code counter may not reflect actual execution time very well.
* As most other profilers, the inclusive costs are estimated by weighted sum of 
all subroutine calls.  
* the per method byte code counter is a SmallInteger (for speed) and with 
modern processor it does not take long (a few minutes) to overflow it (on a 32 
bit machine it max at ~ 1 billion). Don't have the profiler on for too long. 

Derek