Tasks #12260
openMessenger: use setsocketopt to set sk priority field based on message priority prior to sending each message
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Description
This will allow networking stuff to do smart, priority related things with the packets.
Updated by Haomai Wang almost 9 years ago
- Subject changed from simplemessenger: use setsocketopt to set sk priority field based on message priority prior to sending each message to Messenger: use setsocketopt to set sk priority field based on message priority prior to sending each message
Hmm, agreed. We could try this for simple and async messengers. I guess it could help to priority model feature
Updated by Greg Farnum almost 9 years ago
I'm not sure this is feasible: SO_PRIORITY only gets you 6 different levels, and I think I remember investigating this and finding the system effects can be frightening (although I can't find evidence of that, so maybe it was some other feature).
Anyway, see the discussion at https://github.com/ceph/ceph/pull/3353, where we added a (disabled by default) ability to set SO_PRIORITY higher on heartbeat packets.
Updated by Haomai Wang almost 9 years ago
Yeah, I guess we only could set recovery, scrub and normal op at three priority level
Updated by Greg Farnum almost 9 years ago
Well, doing that would run across the same priority inversion issues that Sam is concerned about with generic recovery pieces, where a client op can get stuck waiting for a recovery op to finish, but the recovery message is delayed. :/ Not sure if there's anything really good we can do here or not.