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re: counter-example weakens the probe-causes-freeze correlation

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A pilot-only run froze at t~150.7s (frozen.py: max_pixel_delta=0), found by
accident when the sweep-free experiment aborted at startup and the run flew with
no script probe attached. The tally is now 3-of-3 frozen with the probe versus
1-of-3 without, not 3-versus-0. Still a lean, but not the clean separation the
previous entry claimed, and marked down accordingly -- the fourth time a freeze
conclusion here has had to be softened by one more run.

The sweep-free test itself could not run: ScriptMission is re-allocated per run,
so the address from an earlier run (0xBC7A2A20) read back all zeros. The cheap
self-consistency check ([m+44] must equal the phase's [+244]) rejected it
instead of reporting garbage, which is the part that worked.

Names the cheaper replacement: a BOUNDED pointer scan. Every ScriptMission seen
so far sits in 0xBC79xxxx-0xBC7Axxxx, so ~32MB instead of ~371MB would cut the
sweep cost roughly tenfold. Not yet implemented.
This commit is contained in:
Sylpheed RE agent
2026-08-25 15:38:23 +00:00
parent d086586a0f
commit 22b6541cd9
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docs/re/mission-freeze-resume-spin.md
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@@ -1217,3 +1217,41 @@ cause; if they continue, the per-sample reads are.
**Cost so far:** three attempts to observe a phase advance, all truncated inside
four minutes by a freeze the probe itself may be causing. The arrival transition
at ~143 s was caught only because it happens early.
## 🟡 2026-08-25 — a counter-example weakens the probe correlation
The previous entry made the probe the leading suspect on a clean 3-versus-2
split. **A pilot-only run has now frozen too**, and it came from an accident: the
sweep-free experiment aborted at startup (below), so the run flew with *no*
script probe attached at all. Its pilot state went identical at **t ≈ 150.7 s**
and `frozen.py` confirms `max_pixel_delta=0`.
| probe attached | clean | frozen |
|---|---|---|
| pilot only | 936 s, 1064 s | **150 s** |
| pilot + `phase_watch.py` | — | 70 s, 126 s, 253 s |
So it is **3-of-3 with the probe versus 1-of-3 without**, not 3-versus-0. That is
still a lean, but it is no longer the clean separation the last entry described,
and I am marking it down rather than keeping the stronger reading. This is the
fourth time in this investigation a freeze conclusion has had to be softened by
one more run.
**What would actually settle it** is unchanged and now clearly worth the cost:
alternate probe-on and probe-off windows *within* a single run, several runs, and
compare freeze rate per unit of mission time. Between-run comparisons at n≈3
keep producing splits that the next run erodes.
## 🔴 The sweep-free test could not run: the ScriptMission moves
The plan was to skip `find_mission()`'s two memory sweeps by passing an address
from an earlier run. It does not survive: `0xBC7A2A20` read back **all zeros**
this run, and the cheap self-consistency check (`[m+44]` must equal the phase's
`[+244]`) **rejected it** rather than reporting garbage — which is the one thing
that went right here.
So the object is re-allocated per run and a hard-coded address is not viable.
The sweeps still need replacing to run the experiment; the cheaper version is a
**bounded** pointer scan — every ScriptMission seen so far sat in
`0xBC79xxxx–0xBC7Axxxx`, so scanning ~32 MB instead of the full ~371 MB would cut
the cost roughly tenfold while still finding it. Not yet implemented.