scottlamb/moonfire-nvr v0.7.26

on GitHub

Major changes to sample file directory IO.

• All directory I/O happens on each directory's two-thread pool with threads
  named dir-<PATH>. Formerly, I/O could happen on the per-stream writer
  threads, per-directory reader threads, and occasionally on even the
  tokio worker threads.

• Stream shutdowns are more responsive now. Before they could wait up to
  30 seconds for a connect/frame timeout; now the shutdown request aborts
  these operations.

• Multiple sample file directories are scanned in parallel, speeding
  program startup.

• Streamers write only into a recent frames buffer in RAM, which the directory
  pool workers asynchronously write to disk approximately once per GOP, where
  formerly there was a write call per frame.

  In the new model, streamers never fall behind due to HDD I/O. Instead, frames
  are buffered up to a limit. Recordings are aborted if the pool falls too
  far behind.

  This roughly halves CPU usage as thread hand-offs and syscalls are less common.
  It also enables several desirable future changes:

  • audio recording (which radically increases the number of frames and thus
    would otherwise significantly increase CPU usage).
  • "monitor mode" (allowing live view without recording to disk).
  • further CPU reductions for live view (by skipping all SQLite ops and disk I/O).

• Streamers never acquire the full SQLite database lock, only a per-stream lock.
  They thus never wait on SQLite operations, except indirectly if the tokio thread
  is performing SQLite work on another task. A future change will move all
  SQLite operations to a dedicated thread to avoid such stalls. This was previously
  not viable because it would cause too many thread hand-offs.

bump minimum Rust version to 1.91.