-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On Friday 30 May 2008 11:45 am, Anthony Williams wrote:
One problem is wait_for_any is not sufficient to implement an efficient scheduler. You have to copy all the futures into wait_for_any so each wait_for_any call is O(N). So something like the future_selecter (should be spelled future_selector?) class I mentioned earlier would still be needed.
What do you mean by O(N) in this context?
I mean there are N method requests in my scheduler, and I want to wait until one of them is ready.
You have N futures to wait for. You have to somehow register that you're waiting for each one => you need O(N) operations.
Yes. But the scheduler is going to repeatedly wait on the same N futures (plus or minus one). So as Johan already pointed out, passing iterators to a seperate container of futures to wait_for_any() will cause the sheduler to call wait_for_any N times and take O(N^2) to dispatch N method requests. On the other hand, if the container of futures and wait_for_any are integrated into one class (future_selector), then it doesn't have to do the full setup/tear down with each wait. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) iD8DBQFIQDgf5vihyNWuA4URAnr9AKDFSPDXNZub0bu4C3d/cbGdDJd+VwCgpmsv t+JA1JnP0mQPP4iv61wVjZw= =u825 -----END PGP SIGNATURE-----