Hi Haomai! On Sun, 4 Sep 2016, Haomai Wang wrote: > Background: > Each osd has two heartbeat messenger instances to maintain front/back > network available. It brings lots of connections and messages overhead > in scale out cluster. Actually we can combine these heartbeat > exchanges to public/cluster messengers to reduce tons of > connections(resources). > > Then heartbeat message should be OOB and shared the same thread/socket > with normal message channel. So it can exactly represent the heartbeat > role for real IO message. Otherwise, heartbeat channel's status can't > indicate the real IO message channel status. Because different socket > uses different send buffer/recv buffer, if real io message blocked, > oob message may be healthy. > > Besides OSD's heartbeat things, we have logic PING/PONG lived in > Objecter Ping/WatchNotify Ping etc. For the same goal, they could > share the heartbeat message. > > In a real rbd use case env, if we combines these ping/pong messages, > thousands of messages could be avoided which means lots of resources. > > As we reduce the heartbeat overhead, we can reduce heartbeat interval > and increase frequency which help a lot to the accurate of cluster > failure detection! I'm very excited to see this move forward! > Design: > > As discussed in Raleigh, we could defines these interfaces: > > int Connection::register_oob_message(identitfy_op, callback, interval); > > Users like Objecter linger ping could register a "callback" which > generate bufferlist used to be carried by heartbeat message. > "interval" indicate the user's oob message's send interval. > > "identitfy_op" indicates who can handle the oob info in peer side. > Like "Ping", "OSDPing" or "LingerPing" as the current message define. This looks convenient for the simpler callers, but I worry it won't work as well for OSDPing. There's a bunch of odd locking around the heartbeat info and the code already exists to do the the heartbeat sends. I'm not sure it will simplify to a simple interval. An easier first step would be to just define a Connection::send_message_oob(Message*). That would require almost no changes to the calling code, and avoid having to create the timing infrastructure inside AsyncMessenger... sage > void Dispatcher::ms_dispatch_oob(Message*) > > handle the oob message with parsing each oob part. > > So lots of timer control in user's side could be avoided via callback > generator. When sending, OOB message could insert the front of send > message queue but we can't get any help from kernel oob flag since > it's really useless.. > > Any suggestion is welcomed! > -- > To unsubscribe from this list: send the line "unsubscribe ceph-devel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > > -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
