fork()

Yukihiro Matsumoto matz at netlab.co.jp
Wed Jun 9 08:14:58 CEST 1999


"Tim Peters" <tim_one at email.msn.com> writes:

|Context:  this offshoot of the thread was talking about memory use after a
|fork() call in a copy-on-write implementation of fork.  So long as
|bookkeeping info is stored in object headers, "real GC" is at a real
|disadvantage, in that respect, compared to RC.  Simply because RC won't
|touch something unless *you* do.

Indeed.  Though some "real GC" keeps mark bits in separated pages to
avoid copying bunch of pages in such situation.

BTW, ref counting modifies objects for mere referencing, it causes
copying too.  Also, it would be performance pain if Python's global
thread lock is removed someday, since ref counting requires mutual
lock to protect ref count update.  I'm not sure this problem can be
solved or not.
						matz.




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