Charles-François Natali added the comment: Hello,
> - What about Solaris' /dev/poll? That should be pretty easy to add by someone who has access to a Solaris box: I could use the buildbots, but it'd take a couple iterations to get it right. > - I'm not sure why in case of EINTR you retry with a different timeout; can't > you just return []? Because when I do: selector.select(10) I expect the selector to wait 10 seconds if no event occurs: the fact that a signal comes in shouldn't break the contract made by the API, i.e. that it will return when a FD is ready or the timeout expires. Early return can lead to spurious errors: just imagine you send a request to a busy server: it would be bad to raise a timeout error just because the user put the client in the background with CTRL-Z (which results in SIGSTOP). > - this is probably because I'm paranoid about performances but given that > select() method will be called repeatedly I would not use a decorator. Also, > similarly to what has been done elsewhere in the stdlib, for "critical" parts > I would recommend localizing variable access in order to minimize overhead as > in: > > def select(self, timeout=None): > ... > key_from_fd = self._key_from_fd > ready_append = ready.append > for fd in r | w: > ... > key = key_from_fd(fd) > if key: > ready_append((key, events & key.events)) I find that localizing variables leads to unreadable code, and is tied to the current CPython interpreter implementation: such optimizations belong to the interpreter, not user code. As for the decorator performance overhead, I don't think it weights much compared to the cost of a syscall (+ GIL acquire/release): with decorator: $ ./python -m timeit -s "from selectors import DefaultSelector, EVENT_WRITE; import os; s = DefaultSelector(); s.register(os.pipe()[1], EVENT_WRITE)" "s.select()" 100000 loops, best of 3: 3.69 usec per loop without decorator: $ ./python -m timeit -s "from selectors import DefaultSelector, EVENT_WRITE; import os; s = DefaultSelector(); s.register(os.pipe()[1], EVENT_WRITE)" "s.select()" 100000 loops, best of 3: 3.52 usec per loop That's a 4% overhead, with a single FD that's always ready (and I suspect that most of the overhead is due to the call to time(), not the decorator per se). Also, I'll shortly propose a patch to handle EINTR within C code, so those EINTR wrappers won't be needed anymore. ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue16853> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
