- New fabric-bridge node: initiator mode reads local MXL flow and
transfers via Fabrics (RDMA/TCP); target mode receives remote data
and commits to local MXL flow writer
- Add set_mxl_instance/get_mxl_instance to Node base class
- CMake option DMF_BUILD_FABRICS=OFF by default (needs libfabric)
- Target publishes target_info in status for out-of-band exchange
- Initiator receives target_info via config parameter
- node_runner: track all readers/writers in flow_resources vector,
release them via mxlReleaseFlowWriter/mxlReleaseFlowReader before
destroying the MXL instance (fixes 'leaked flow writer' warning)
- node_runner: remove_writer/remove_reader commands now also release
the MXL flow resources, not just reset the node's optional<>
- engine: call process_manager.stop_all(graph) on shutdown to kill
child node processes (prevents orphaned passthrough processes)
- graph: add get_node_mut() for process_manager to update node state
- process_manager: implement stop_all(Graph&) that SIGTERMs all
running node processes
- passthrough: reduce logging to first-grain and realign-once only
- tests: update flow format assertion to match NMOS
(urn:x-nmos:format:video instead of video/v210)
The fundamental issue: mxlSleepUntil/mxlSleepForNs blocks the entire
thread, making LWS unresponsive and causing control commands to hang.
Meanwhile, LWS poll(1) adds latency that makes grain timing unreliable.
Solution: run node->process() in a dedicated thread that can freely use
mxlSleepUntil for precise grain timing, while the main thread runs
control_server->poll(10) for LWS event handling.
Passthrough now uses mxlSleepUntil(deadline) matching the mxl-gst-sink
Cursor pattern, with 2-grain read delay for buffering.
mxlSleepUntil blocks the entire thread including LWS poll, causing the
control server to become unresponsive and grains to be missed. Instead,
check mxlGetNsUntilIndex and skip process() if the grain isn't due yet
(>2ms away). The node loop spins with poll(1) keeping LWS responsive,
and only attempts a grain read when it's nearly due.
Match the mxl-gst-sink pattern: sleep until the next grain's delivery
deadline using mxlSleepUntil, then read with a short 5ms timeout.
Uses 2-grain read delay (40ms at 50fps) for buffering headroom.
Previous approach of mxlSleepForNs + 20ms GetGrain timeout caused the
passthrough to fall behind: each iteration took ~25ms (poll+sleep+read),
missing grains and perpetually chasing headIndex via realign.
Instead of chasing headIndex from mxlFlowReaderGetRuntimeInfo (which
points to the NEXT grain to be written, causing perpetual TOO_EARLY),
the passthrough now uses mxlTimestampToIndex + mxlGetNsUntilIndex for
proper timing alignment, matching the pattern used by mxl-gst-sink.
Key changes:
- realign() computes read_index from current TAI time minus 1 grain delay
- process() uses mxlSleepForNs to wait until the target grain is due
- on_add_reader fetches grain_rate from mxlFlowConfigInfo
- Removed separate write_index_ (uses grain_info.index for writer)
- control_server: add Connection: close header + always return -1 after
HTTP response to force-close connection. Without this, lws_service()
blocks forever after the first POST /cmd, freezing the node process loop.
- passthrough: initialize read_index_ to runtime.headIndex when reader
is added (prevents TOO_EARLY errors on first read)
- passthrough: handle MXL_ERR_OUT_OF_RANGE_TOO_EARLY in addition to
TOO_LATE (both jump to head index)
- passthrough: use grain_info.index as writer index instead of separate
write_index_ counter (MXL writers must use TAI-based grain indices)
- passthrough: reduce grain read timeout from 100ms to 20ms for tighter
loop with LWS poll
- node_runner: add 'status' command handler that sends node status
back via control server
Johanness