Re^3: How do I get a unique Perl Interpreter ID?

[zwon]

clone operation has almost nothing left to do beyond creating a bunch of entries in a page table with copy-on-write tags, it's not hard to imagine it eventually being possible for multiple interpreters to get cloned in the same microsecond.

Have you tried to actually timing it? Only kernel have access to the page table, and even if perl could mark pages as copy-on-write it wouldn't help, as it has to change addresses, so no COW when cloning interpreters. Perl has to duly copy all data from the original interpreter to the new one, and the more modules loaded the more data it has to copy, the more time it takes.

[wrog]

Actually, now that I think about it some more, the real issue here is that once you have concurrency, you can just as easily have cloning happening in parallel, at which point, it doesn't actually matter how long it takes to perform a single thread-clone.

That is, as long as there is the possibility that two cloning operations in parallel threads can finish at the same time, we're toast if we're depending solely on the clock to distinguish the resulting interpreters.