On 2/25/07, Armin Rigo <[EMAIL PROTECTED]> wrote: > Hi Adam, > > On Thu, Feb 15, 2007 at 06:17:03AM -0700, Adam Olsen wrote: > > > E.g. have a wait(events = [], timeout = -1) method would be sufficient > > > for most cases, where an event would specify > > > > I agree with everything except this. A simple function call would > > have O(n) cost, thus being unacceptable for servers with many open > > connections. Instead you need it to maintain a set of events and let > > you add or remove from that set as needed. > > I just realized that this is not really true in the present context. > If the goal is to support programs that "look like" they are > multi-threaded, i.e. don't use callbacks, as I think is Joachim's goal, > then most of the time the wait() function would be only called with a > *single* event, rarely two or three, never more. Indeed, in this model > a large server is implemented with many microthreads: at least one per > client. Each of them blocks in a separate call to wait(). In each such > call, only the events revelant to that client are mentioned. > > In other words, the cost is O(n), but n is typically 1 or 2. It is not > the total number of events that the whole application is currently > waiting on. Indeed, the scheduler code doing the real OS call (e.g. to > select()) can collect the events in internal dictionaries, or in Poll > objects, or whatever, and update these dictionaries or Poll objects with > the 1 or 2 new events that a call to wait() introduces. In this > respect, the act of *calling* wait() already means "add these events to > the set of all events that need waiting for", without the need for a > separate API for doing that.
That would depend on whether Joachim's wait() refers to the individual tasks' calls or the scheduler's call. I assumed it referred to the scheduler. In the basic form it would literally be select.select(), which has O(n) cost and often fairly large n. -- Adam Olsen, aka Rhamphoryncus _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
