Is this a bug? Python intermittently stops dead for seconds

Charlie Strauss cems at earthlink.net
Sun Oct 1 18:19:45 CEST 2006


On Oct 1, 2006, at 9:48 AM, Fredrik Lundh wrote:
> charlie strauss wrote:
>
>> level0:  newly created objects
>> level1:  objects that survived 1 round of garbage collection
>> level2:  objects that survivied 2+ rounds of gargbage collection
>>
>> Since all of my numerous objects are level2 objects, and none of
>> them are every deallocated, then I should never trip the GC for
>> these.
>
> your understanding of generational GC is a bit fuzzy, it seems.   
> that an
> object is promoted to a higher level means that it's not inspected  
> quite
> as often as lower-level objects, not that it's never inspected at all.


As I understand it, level2 (and level1) objects only undergo gc when  
more than 10 of them is deallocated.  Since I never deallocate, this  
should not be tripped right?

In any case regarding your other comments:

>> Could you clarify that for me.  GC really has three components
>> two it:  1) finding and freeing unrefernced memory by refer
>> refer counts 2)  cycle removal and 3)  defragementing the
>> storage stack.  If I turn off GC, don't I lose all of these?
>>
>
> CPython always does (1), only does (2) if cycle-breaking GC isn't
> disabled, and never does (3).


Never does 3?  then how does it compact it's memory allocation area?   
Surely it does not rely on the OS to manage every small object as a  
separate memory allocation.

And just to be clear: are you saying that when I do a gc.disable this  
only turns off 2 and not 1?  The docs don't say that as far as I can  
tell.

> in your case, it's (2) that takes more and more time, simply because
> you're creating tons of non-trivial objects.  to see what's going  
> on in
> there, add
>
>      import gc
>      gc.set_debug(gc.DEBUG_STATS)
>
> to the top of your program, and look at the status messages that  
> appear
> just before each "Big Gap" message.


Could you be a bit more explicit.  I'm new to the gc module.  Sorry  
to be slow but I don't know what "looking at the status message" means.




>
> </F>
>
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