[Python-Dev] Tagged integers (original) (raw)

Tim Peters tim.peters at gmail.com
Fri Jul 16 02:57:26 CEST 2004

[Christian Tismer]

... Boehm GC might become feasible. If we then can write C extensions without having to think of reference counts, code would be simplified quite much, and I would save 80 percent of debugging time.

There's no escape from gc debugging nightmares at the C level, regardless of gc strategy. With Boehm gc (Bgc) you have to ensure that all live objects are reachable from what Bgc guesses is the current root set, and screwing that up is just as deadly as screwing up refcounts. It's harder to debug, though, because refcounting is very simple to picture, while Bgc is a relatively huge pile of complicated code in its own right. I'm sure Neil Schemenauer still has fond memories of the pleasant days he spent trying to account for Tk crashes last time he tried hooking Bgc to Python . Bgc has a special entry point to call, to register roots that Bgc can't find on its own -- guess how you find out which roots those are? One crash at a time, and in the presence of threads you're damned lucky to get a repeatable test case.

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