Files
threadx/test/tx
Frédéric Desbiens 24d1f278c2 Decorrelated the wait abort ISR test's interrupt source from the thread it samples (#743)
threadx_thread_wait_abort_and_isr_test waits for the periodic timer interrupt to
land while the preempt disable flag is set. The same interrupt also puts the
semaphore that wakes the thread being sampled, so the two run in lockstep: the tick
wakes thread 0, thread 0 does a fixed amount of work and suspends, and the next tick
arrives a fixed interval later with thread 0 in the same place every time. That is
the resonance the handler's own comment describes, and perturbing the handler's
duration only shifts the phase rather than breaking the correlation. The window
itself is a few instructions wide, so a sampler locked to the thread's own cycle can
miss it indefinitely, which is what #644 and #649 measured and worked around.

The simulator's timer thread waits on _tx_linux_timer_semaphore with a one-tick
deadline and delivers an interrupt early when the semaphore is posted, which the port
already relies on in _tx_thread_schedule. The test now runs a plain POSIX thread that
posts it, injecting interrupts at moments unrelated to the tick grid and sampling
thread 0 at arbitrary points in its cycle rather than the same one. The injector posts
only when nothing is outstanding, so interrupts can never be queued faster than they
are serviced. It is confined to the Linux simulation port and no port file changes.

The count of windows asked for goes back to ten, on the same reasoning that lowered
it to three: ask for what a run can actually reach. Measured over six build
configurations of a branch carrying this change, every one reaches ten of ten in under
a second, against one to three of three previously with three of the six pinned at the
180 second budget. The budget and the zero window ceiling are untouched, so a run that
somehow still falls behind behaves exactly as it does today.

The SMP copy deliberately does not get the injector, and its count stays at twenty. It
has never been in the slow mode, and injecting interrupts there measurably hurts:
8.9 seconds against 0 to 1 for the same twenty windows, which is the extra interrupt
traffic contending across the simulated cores. Only the tx copy has the problem this
solves, so only the tx copy changes; the budget and ceiling logic stays identical
between them.

Verified on this branch: the tx suite passes 105 of 105 with the test at 0.44 seconds,
and four direct runs reach ten of ten in 0 to 1 seconds. The SMP suite passes 117 of
117 unmodified, with its own test at 0 to 1 seconds over four runs.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>
2026-09-16 09:18:41 -04:00
..