With TOTK_TRACE=sched, TOTK_CRIT=<lo>-<hi> records every state change and wake of the guest threads and every
present over those frames (runtime/kernel.c crit_add from acct() and wake(), crit_frame at the present) and writes
them to TOTK_CRIT_OUT at the last frame. tools/crit_path.py walks back from each present through the waits to the
thread whose signal ended them and splits the frame interval by thread and state; the sums equal the interval.
A 1.4.3 fight: with the replay on the submitting thread the path is 7.3 ms of replay on the render thread and 4.3 ms
of guest code; with TOTK_REPLAY_ASYNC=1 it is 10.1 ms of guest code through the fork-join of the main thread and five
workers, at the same frame interval.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
