Bretheren,

I have read much about perl's garbage collection infrastructure, and I am familiar with the advantages and disadvantages of mark&sweep vs. reference counting. I understand that the reference counting takes care of most of the memory deallocation throughout the program's execution, and that upon shutdown of the interpreter, a full-on mark&sweep gc run is executed, and thus self-referential and circular-referential nodes can be collected and released to the kernel.

This makes sense to me in the context of a host program that runs an embedded interpreter, such as apache running a mod_perl system that re-uses modules and would not want to accumulate memory leaks.

But for a normal perl program, let's say a simple non-interactive script running from the command line as a seperate process, what benefit is there from doing exhaustive and time-consuming garbage collection just before exiting and after all productive work is done? When a process exits, ALL the memory is released back to the kernel - interpreter memory, program-space memory - all of it. Circular references or not. Isn't this last minute gc just a big waste of time for the cases (outside of persistent runtime environments) where any garbage would be collected?

Or am I missing something?

Your enlightenment would be most appreciated.

Thanks,
- Paul

In reply to Why bother with the mark and sweep garbage collection on non-embedded interpreter shutdown? by dynamo

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