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style: run oxfmt repo-wide

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First full pass of the pnpm fmt toolchain: markdown table alignment,
TOML array wrapping, CSS/HTML expansion in the enclosure concept page.
No content changes; mermaid blocks untouched.
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Julien Calixte
2026-07-14 12:40:51 +02:00
parent 1493ee246f
commit 43d80b518f
35 changed files with 1140 additions and 715 deletions
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32
docs/notes/boot-time-budget.md
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@@ -16,25 +16,25 @@
From the boot serial log (power-on → first editor frame + input loop live):
| Phase | ~ms | Lever |
| --- | ---: | --- |
| ROM + 2nd-stage bootloader + app image load | ~550 | flash speed (DIO now; QIO / 80 MHz ≈ −200 ms, speculative) |
| PSRAM init + **memtest** + heap | ~920 | `CONFIG_SPIRAM_MEMTEST=n` → **−730 ms** (kept **on**: a real HW sanity check on a hand-wired board) |
| EPD reset + init | ~130 | fixed panel bring-up |
| **Splash full refresh** | ~1850 | e-ink floor — see below |
| SD mount + note load | ~70 | quick on the genuine 32 GB SDHC |
| USB host install + git thread spawn | ~60 | background |
| **First editor render** (full-area partial) | ~680 | already fixed from ~1870 ms (was a *second* full refresh) |
| **Total** | **~4260** | |
| Phase | ~ms | Lever |
| ------------------------------------------- | --------: | --------------------------------------------------------------------------------------------------- |
| ROM + 2nd-stage bootloader + app image load | ~550 | flash speed (DIO now; QIO / 80 MHz ≈ −200 ms, speculative) |
| PSRAM init + **memtest** + heap | ~920 | `CONFIG_SPIRAM_MEMTEST=n` → **−730 ms** (kept **on**: a real HW sanity check on a hand-wired board) |
| EPD reset + init | ~130 | fixed panel bring-up |
| **Splash full refresh** | ~1850 | e-ink floor — see below |
| SD mount + note load | ~70 | quick on the genuine 32 GB SDHC |
| USB host install + git thread spawn | ~60 | background |
| **First editor render** (full-area partial) | ~680 | already fixed from ~1870 ms (was a _second_ full refresh) |
| **Total** | **~4260** | |
Two lines carry the weight: the **splash full refresh (~1.85 s)** and the
**first editor render (~0.68 s)**. Everything else is ≤ ~0.9 s combined, and the
biggest of *those* — the ~0.73 s PSRAM memtest — is a deliberate keep.
biggest of _those_ — the ~0.73 s PSRAM memtest — is a deliberate keep.
## The insight: one full refresh is unavoidable, so the splash is nearly free
After power-on the panel controller's `0x26` "previous" RAM bank holds garbage. A
partial refresh *diffs the new image against that bank*
partial refresh _diffs the new image against that bank_
([`../tradeoff-curves/epd-refresh-latency.md`](../tradeoff-curves/epd-refresh-latency.md)),
so the **first clean paint must be a full refresh** (~1.9 s) to establish a known
image. There is no way around this on this panel short of a different waveform.
@@ -42,12 +42,12 @@ image. There is no way around this on this panel short of a different waveform.
That reframes two things:
- **The splash costs almost nothing.** Boot needs one full refresh regardless; the
splash simply *is* that refresh, turned into a "boot is happening" affordance.
splash simply _is_ that refresh, turned into a "boot is happening" affordance.
Dropping the splash would **not** save the 1.9 s — the editor's first frame would
then have to be the full refresh instead. (This is exactly what the old boot did
and why it paid *two* full refreshes.)
and why it paid _two_ full refreshes.)
- **The v0.1 win was removing the second full refresh, not the first.** Once the
splash has seeded a clean baseline, the editor rides in on a full-area *partial*
splash has seeded a clean baseline, the editor rides in on a full-area _partial_
(~0.63 s) instead of a second full refresh (~1.9 s) — the ~1.25 s saving that
took cold boot from ~5.5 s to ~4.26 s. Verified clean on-panel (no splash
ghost behind the editor text).
@@ -60,7 +60,7 @@ To go from ~4.26 s to ≤ 3 s needs ~1.26 s cut. The honest lever list:
reasonable once the board is no longer hand-wired.
- **Faster flash boot (QIO / 80 MHz):** ~−0.2 s, speculative, needs a bench check.
- **Overlap cheap init under the splash busy-wait:** SD mount + note load + USB
install (~0.13 s total) currently run *after* the splash refresh returns, but
install (~0.13 s total) currently run _after_ the splash refresh returns, but
the refresh is a `wait_while_busy` spin — those could be kicked off before it.
Saves ~0.1 s at most.