GPU start/stop being logged as INT64_MAX

[elliottslaughter]

I have a profile where GPU task start/stop times are being logged as 0x8000000000000000, i.e., INT64_MAX.

What is this supposed to mean exactly? What is the profiler supposed to do with this?

[src/state.rs:4746:17] &record = GPUTaskInfo {
    op_id: OpID(
        460,
    ),
    task_id: TaskID(
        454,
    ),
    variant_id: VariantID(
        1192,
    ),
    proc_id: ProcID(
        2089670227099910148,
    ),
    create: Timestamp(
        553760398,
    ),
    ready: Timestamp(
        871627394,
    ),
    start: Timestamp(
        871771612,
    ),
    stop: Timestamp(
        871937060,
    ),
    gpu_start: Timestamp(
        9223372036854775808,
    ),
    gpu_stop: Timestamp(
        9223372036854775808,
    ),
    creator: Some(
        EventID(
            9223372105692741656,
        ),
    ),
    critical: Some(
        EventID(
            9223372105786064901,
        ),
    ),
    fevent: EventID(
        9223372105771384836,
    ),
}

Log file: 0.log