Mon - Prioritize messages » History » Version 1
Jessica Mack, 06/23/2015 09:22 PM
1 | 1 | Jessica Mack | h1. Mon - Prioritize messages |
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2 | 1 | Jessica Mack | |
3 | 1 | Jessica Mack | h3. Summary |
4 | 1 | Jessica Mack | |
5 | 1 | Jessica Mack | Some messages are more important to finish quickly than others. Some other messages take less time than others. Lots of client messages, in a big enough cluster, can and will hinder progress of another messages (some of them even critical) simply due to the amount of messages to be handled. |
6 | 1 | Jessica Mack | The monitors should thus prioritize their own, mission-critical messages over any other conceivable message. The rationale should be simple: if the client waits a small fraction of a second longer, it should be okay; if the monitor waits to handle a thousand fractions of second to handle a critical message (such as a paxos lease extension), it may trigger a timeout and cause unnecessary havoc. |
7 | 1 | Jessica Mack | |
8 | 1 | Jessica Mack | h3. Owners |
9 | 1 | Jessica Mack | |
10 | 1 | Jessica Mack | * Joao Eduardo Luis (Inktank) |
11 | 1 | Jessica Mack | * Name (Affiliation) |
12 | 1 | Jessica Mack | * Name |
13 | 1 | Jessica Mack | |
14 | 1 | Jessica Mack | h3. Interested Parties |
15 | 1 | Jessica Mack | |
16 | 1 | Jessica Mack | * Name (Affiliation) |
17 | 1 | Jessica Mack | * Name (Affiliation) |
18 | 1 | Jessica Mack | * Name |
19 | 1 | Jessica Mack | |
20 | 1 | Jessica Mack | h3. Current Status |
21 | 1 | Jessica Mack | |
22 | 1 | Jessica Mack | There's no support for this on the monitor. From a quick look on ceph's tree, it looks like the messenger and DispatchQueue already understand Message priority, and one can use Message::set_priority() to define a message's priority. |
23 | 1 | Jessica Mack | This blueprint can be addressed on its own, but it would be preferable if it were addressed after addressing another submitted blueprint for Giant: [[mon - Independently dispatch non-conflicting messages|mon: Independently dispatch non-conflicting messages]] |
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25 | 1 | Jessica Mack | h3. Detailed Description |
26 | 1 | Jessica Mack | |
27 | 1 | Jessica Mack | Once defined which messages should have higher priority when handled by the monitor, this task should be a matter of sending messages from the monitors to another monitors setting a higher priority on some of the messages. |
28 | 1 | Jessica Mack | |
29 | 1 | Jessica Mack | For instance, with regard to message priority: |
30 | 1 | Jessica Mack | |
31 | 1 | Jessica Mack | MMonPaxos > MMonElection > MMonGetMap > MMonProbe > MMonQuorumService > PaxosServiceMessage > MMonSync |
32 | 1 | Jessica Mack | |
33 | 1 | Jessica Mack | h3. Work items |
34 | 1 | Jessica Mack | |
35 | 1 | Jessica Mack | h4. Coding tasks |
36 | 1 | Jessica Mack | |
37 | 1 | Jessica Mack | # Assess priorities |
38 | 1 | Jessica Mack | # Add monitor interface to appropriately send messages with an appropriate priority (instead of having to do it manually for each single message) |
39 | 1 | Jessica Mack | # Unit-tests |
40 | 1 | Jessica Mack | ** parse through logs (yuck!) |
41 | 1 | Jessica Mack | ** add a workunit that sends a bunch of messages with different priorities and expects replies in a priority-based order (this needs some thought!) |
42 | 1 | Jessica Mack | |
43 | 1 | Jessica Mack | h4. Documentation tasks |
44 | 1 | Jessica Mack | |
45 | 1 | Jessica Mack | # doc: document message priorities |