commit c9030a0a499e7708daaeab8d7fedaac5e8733c07
author Chinglin Yu <chinglinyu@google.com> Tue Jul 16 11:30:33 2024 +0800
committer Chinglin Yu <chinglinyu@google.com> Tue Jul 16 11:30:33 2024 +0800
tree 574ae55164a37f4773d4089367cbf4e08f4342f7
parent 8a25b41fbc37a49d26f352ed8ecb9abdea588dfb

tp: support remote clock sync

Implement injestion of the RemoteClockSync message for multi-machine
tracing sessions. A RemoteClockSync message consists of multiple
SyncedClocks messages, each of which contains ClockSnapshot taken on the
remote client and host sides:

```
  remote_clock_sync {
    synced_clocks {
      client_clocks {
        clocks {
          clock_id: 6 # CLOCK_BOOTTIME in the client.
          timestamp: 10000
        }
        # Other clocks domains
      }
      host_clocks {
        clocks {
          clock_id: 6 # CLOCK_BOOTTIME in the host
          timestamp: 111000
        }
      }
    }
    # more synced_clocks {}
  }
```

A round of clock synchronization consists of 4 snapshots taken in the
order of client, host, client, host. The process is repeated with an
interval of 30 seconds.

The proto trace reader injests this message to make an estimation of
clock offset between client and host for converting timestamps from
client to the host clock domains. The trace processor takes an average
of the estimated offset in the RemoteClockSync message to provide a more
stable and predictable offset value. For more details, refer to section
"Clock Synchronization" of go/crosetto-vm-tracing.

Bug: 347623660
Change-Id: Ide96e8fb8101b76464416effe971f57ac3c33374