20230202_zeroed_startevent_of_historic_op.md

20230202_zeroed_startevent_of_historic_op.md

The zeroed StartEvent problem

After running some client IO:

[rzarzynski@o06 build]$ bin/ceph tell osd.2 dump_historic_slow_ops
...
            {
                "type": "client_request",
                "id": 216614,
                "detail": {
                    "time_event": {
                        "name": "crimson::osd::TrackableOperationT<crimson::osd::ClientRequest>::StartEvent",                                                                                                     
                        "initiated_at": "0.000000"
                    },
                    "blocking_event": {
                        "name": "crimson::osd::ConnectionPipeline::AwaitActive",
                        "initiated_at": "2023-02-02T01:08:59.502627+0000"
                    },
                    "blocking_event": {
                        "name": "crimson::osd::ConnectionPipeline::AwaitMap",
                        "initiated_at": "2023-02-02T01:08:59.502658+0000"
                    },
                    "blocking_event": {
                        "name": "crimson::osd::OSDMapGate<(crimson::osd::OSDMapGateType)0>::OSDMapBlocker",                                                                                                       
                        "initiated_at": "0.000000"
                    },
                    "blocking_event": {
                        "name": "crimson::osd::ConnectionPipeline::GetPG",
                        "initiated_at": "2023-02-02T01:08:59.502683+0000"
                    },
                    "blocking_event": {
                        "name": "crimson::osd::PGMap::PGCreationState",
                        "initiated_at": "0.000000"
                    },
                    "time_event": {
                        "name": "crimson::osd::TrackableOperationT<crimson::osd::ClientRequest>::CompletionEvent",                                                                                                
                        "initiated_at": "2023-02-02T01:08:59.502908+0000"
                    }
                }
            }
        ]
    },

Fix PR: ceph/ceph#50019.