Il 12/03/2012 09:59, Zhi Yong Wu ha scritto: >> However, then I noticed that qemu_can_send_packet is not called very >> much, and I do not understand why qemu_net_queue_send and >> qemu_net_queue_send_iov do not call qemu_can_send_packet before calling >> deliver/deliver_iov. > >> If they did, hubs could then do their own flow control via can_receive. >> When qemu_send_packet returns zero you increment a count of in-flight >> packets, and a sent-packet callback would decrement the same count. > > sent-packet callback is sent_cb here? i noticed that sent_cb is currently > NULL.
Yes. >> When the count is non-zero, can_receive returns false (and vice versa). >> Can you elaborate this? since can_receive is called finally by >> qemu_send_packet, >> how can can_receive return false or true based on the count? Based on counts from the previous sends. Paolo
