Author: Armin Rigo <ar...@tunes.org> Branch: Changeset: r76560:623926e972d5 Date: 2015-03-25 15:47 +0100 http://bitbucket.org/pypy/pypy/changeset/623926e972d5/
Log: Expand on transaction.time and .clock diff --git a/pypy/doc/stm.rst b/pypy/doc/stm.rst --- a/pypy/doc/stm.rst +++ b/pypy/doc/stm.rst @@ -350,10 +350,17 @@ ``stmidset`` classes using the identity of the key. * ``time.time()`` and ``time.clock()`` turn the transaction inevitable - in order to guarantee that a call that appears to be later will - really return a higher number. If getting slightly unordered - results is fine, use ``transaction.time()`` or - ``transaction.clock()``. + in order to guarantee that a call that appears to be later will really + return a higher number. If getting slightly unordered results is + fine, use ``transaction.time()`` or ``transaction.clock()``. The + latter operations guarantee to return increasing results only if you + can "prove" that two calls occurred in a specific order (for example + because they are both called by the same thread). In cases where no + such proof is possible, you might get randomly interleaved values. + (If you have two independent transactions, they normally behave as if + one of them was fully executed before the other; but using + ``transaction.time()`` you might see the "hidden truth" that they are + actually interleaved.) * ``transaction.threadlocalproperty`` can be used at class-level:: _______________________________________________ pypy-commit mailing list pypy-commit@python.org https://mail.python.org/mailman/listinfo/pypy-commit
