Diagnostics PageRank Example Stuck

[timelydataflow]

Diagnostics PageRank Example Stuck

[utaal]

Hi, thanks for the report.
I can't reproduce this on my Mac (on the timely-dataflow and diagnostics master branch); are you on Linux?

[gatoWololo]

Okay. I found the problem. I was using my own Cargo patch version of timely-dataflow. I had extended the TimelyEvent enum with my own variant. That seems to cause the locking behavior (even though I don't use the variant anywhere in the code...).

[utaal]

Right! Yes, the messages are encoded using https://github.com/TimelyDataflow/abomonation, which is essentially just writing out the in-memory representation of rust objects. This means that even a minor difference in the definition of Events can cause things to break in unexpected ways.

If you need a custom event, you either need to change TimelyEvent in both the timely program and in connect (within diagnostics) by changing its dependency to point to your custom timely, or (maybe preferably) you can just register a separate event stream using something like https://github.com/TimelyDataflow/timely-dataflow/blob/4b4752ec7447253ac61c9804c9cf6406dabfc281/timely/examples/logging-send.rs#L21-L23

You can see how to make a receiver here: https://github.com/TimelyDataflow/diagnostics/blob/master/tdiag/src/commands/graph.rs#L51-L53

You can also customise how events are written out, by registering a different callback to the log_register: this way you can emit, for example, bincode or json-encoded events. We use the binary abomonation encoding because it's a lot faster than json and, afaik, faster than bincode (which is important for chatty logging streams like TimelyEvent).