The frame-rate test sylpheed-port and I agreed was the only clean route left.
Same strips, same screen, --framerate_limit=15 against the default. The limit
demonstrably took effect: the title settled at 862 s against 241 s.
First, a gate this work should have had from the start. A slope is only a rate if
its residual is random, so count sign changes in the residual:
default 1299x1303 -4.348 rms 3.33 43/111 OK
883x1134 +4.284 rms 3.08 21/76 SYSTEMATIC
890x1134 +4.284 rms 3.19 15/54 SYSTEMATIC
limit 15 1299x1303 -2.032 rms 1.51 44/83 OK
883x1134 +2.003 rms 1.12 36/61 OK
890x1134 +1.999 rms 0.74 12/37 SYSTEMATIC
So one of the two strips I quoted as "agreeing to three significant figures"
FAILS the linearity gate at default fps: that agreement was between a rate and a
slope through a curve. The port had already caveated the claim for a different
reason; this weakens it further from my own side.
The result, on the one group passing the gate at both settings: -4.348 px/frame
at default against -2.032 at limit 15, a ratio of 2.14.
THE LEAF IS NOT FRAME-LOCKED. A fixed number of units per submitted frame
predicts px/frame unchanged; it changed by 2.14x. Dead.
A simple wall-clock model is dead too, in the other direction: fewer frames per
second means more wall time per frame, so a time-driven leaf should move MORE
px/frame at a lower limit. It moved LESS. Neither model fits and I have no third.
Reach: the effective frame rate was NOT measured. The timing instrument I added
polls for the capture log, which is created when the capture is ARMED rather than
when it finishes, so it reported 0.728 s and is void. The 3.6x boot slowdown says
the limit took effect, not that fps went 28 -> 15. The RATIO is measured; the
absolute rate still is not.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Wuu56cE8vJGTBtn1ppsk8v
The withdrawal last iteration was caused by `rm -f /tmp/xenia-canary.lock` --
the obvious way past a lock orphaned by kill -9, which also disables the guard
for every later launch. Three instances ended up live at once, sharing
/tmp/xenia_pad.txt and display :98, and silently confounded an input experiment.
Care is not a fix, so this is tooling. ensure_single_emulator.sh counts live
instances, stops them (plain kill, then -9, each with a bounded wait), verifies
ZERO, and only then removes the lock -- refusing loudly if any remain. The lock
is never removed before the condition it guards against is verified absent.
FOUR scripts did the bare `rm -f`, and only two were mine from today:
menu_loop_session.sh, title_draw_capture.sh, poke_control.sh and
resume_reliability.sh. So the footgun was corpus-wide rather than introduced
this session. All four now route through the guard.
The guard is controlled rather than assumed: run against a deliberately started
live instance it reports "1 instance(s) live -- stopping them", ends at 0 with
the lock cleared, and exits 0. A guard that only ever passes on an already-clean
slate would prove nothing.
It also kills by process NAME. `pkill -f xenia_canary` matches the shell running
it -- that has now cost this corpus three commands, one of them a cleanup that
died halfway and left the very instances it was meant to remove.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Wuu56cE8vJGTBtn1ppsk8v
While chasing the draw-stream question I found THREE xenia instances running
simultaneously (started 15:39, 15:44, 16:12), which violates the "one emulator at
a time" hard rule and confounds the finding I recorded last iteration.
All three read the same /tmp/xenia_pad.txt and share display :98. A press written
to that file is delivered to EVERY instance, while `screenshot` grabs whichever
window is topmost -- not necessarily the one that acted on it. So "(A) was
delivered and the screen did not change" may simply be two different emulators,
and the keystroke-level confirmation proves only that SOME instance received it.
The navigation.md entry claiming the boot title's "2 of 2" is no longer 2 of 2 is
withdrawn as unsupported, pending a clean re-run.
The cause was mine. run-canary's lockfile is the IMPLEMENTATION of the one-at-a-
time rule; a kill -9 orphans it, and the obvious unblock -- rm -f the lock --
also disables the guard for every later launch. I did that more than once today.
METHOD gains two entries. A lockfile is the rule, not an obstacle to it: clear a
stale lock only after confirming zero live instances, and COUNT them rather than
trusting a kill landed, because a plain kill is asynchronous and a -9 on a stuck
process can take seconds. When a guard blocks you, the question is whether the
condition it guards against is present, not how to remove the guard.
And a third instance of pgrep -f matching the shell that runs it -- this time it
killed a cleanup command halfway through, leaving the emulators alive and the
lock in place. Already recorded for wait-loops; promoted to "reach for -C first".
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Wuu56cE8vJGTBtn1ppsk8v
