On Thu, 2005-02-17 at 22:38, Tim Peters wrote:
Then you allocate a small object, marked 's':

bbbbbbbbbbbbbbbsfffffffffffffffffffffffffffffff

Isn't the whole point of obmalloc is that we don't want to allocate "s" on the heap, since it is small? I guess "s" could be an object that might potentially grow.


One thing to take from that is that LFH can't be helping list-growing
in a direct way either, if LFH (as seems likely) also needs to copy
objects that grow in order to keep its internal memory segregated by
size.  The indirect benefit is still available, though:  LFH may be
helping simply by keeping smaller objects out of the general heap's
hair.

So then wouldn't this mean that there would have to be some sort of small object being allocated via the system malloc that is causing the poor behaviour? As you mention, I wouldn't think it would be list objects, since resizing lists using LFH should be *worse*. That would actually be something that is worth verifying, however. It could be that the Windows LFH is extra clever?


I'm afraid the only you can know for sure is by obtaining detailed
memory maps and analyzing them.

Well, it would also be useful to find out what code is calling the system malloc. This would make it easy to examine the code and see if it should be calling obmalloc or the system malloc. Any good ideas for easily obtaining this information? I imagine that some profilers must be able to produce a complete call graph?


Evan Jones

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