2c1c590c9e
Without CONFIG_FATFS_USE_FASTSEEK every long/backward lseek in the 263 MB pack walks the FAT cluster chain over SPI (~190 ms), and libgit2 pays ~8 such seeks per loose-object write. The CLMT makes lseek O(1) for read-mode files; verified on device: far seek 198.7 -> 20.4 ms, splice commit 6.5 -> 2.8 s.
77 lines
4.5 KiB
Plaintext
77 lines
4.5 KiB
Plaintext
# Rust often needs a bit of an extra main task stack size compared to C (the default is 3K)
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# You might have to increase this further if you allocate large stack variables in the main task.
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# Bumped for the TLS handshake (Spike 6): mbedtls runs on the calling task and
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# wants several KB of stack on top of the app's own usage. 12 KB ran the editor
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# AND a full TLS-on-main handshake on hardware — the last-known-good value for
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# this shared stack.
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#
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# Spike 7 briefly bumped this to 96 KB because libgit2's push chain is far deeper
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# (~67 KB measured for a trivial config write: nearly every function puts a 4 KB
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# `char path[GIT_PATH_MAX]` on the stack and init→config→FATFS→wear-leveling
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# nests ~10 deep). But this sdkconfig is SHARED with the editor build, so that
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# forced the editor to over-reserve ~80 KB for nothing. Git now runs on its own
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# large-stack thread instead (git_push.rs — GIT_STACK via
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# std::thread::Builder::stack_size), so this drops back to the Spike-6 value.
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# (The "time() only works on the main task" theory was a misdiagnosis: that
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# iteration ran git on a std::thread with the DEFAULT 4 KB stack and just
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# overflowed sooner — it was always stack depth, never thread-vs-main.)
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CONFIG_ESP_MAIN_TASK_STACK_SIZE=12288
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# Increase a bit these stack sizes as they are also a bit too small by default
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CONFIG_ESP_SYSTEM_EVENT_TASK_STACK_SIZE=4096
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CONFIG_FREERTOS_IDLE_TASK_STACKSIZE=4096
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# You might have to increase this further if you spawn your own Rust threads
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# that allocate large stack variables; or better yet - use
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# `std::thread::Builder::new().stack_size(XXX)` for spawning
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CONFIG_PTHREAD_TASK_STACK_SIZE_DEFAULT=4096
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# FatFS long filenames (Spike 3 — SD). Default is 8.3-only, which rejects the
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# persistence module's atomic-save temp name (`notes.md.tmp` has two dots).
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# LFN on the heap keeps the working buffer off the (small) task stack.
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CONFIG_FATFS_LFN_HEAP=y
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# PSRAM (Spike 7 — the git working set needs it; the docs memory plan budgets
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# ~1.5 MB PSRAM for pack/delta work, and the rope buffer lives there too). This
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# board is an ESP32-S3-WROOM-1-N16R8 → 8 MB *octal* PSRAM, so OCT mode is
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# required (quad would fail to init). USE_MALLOC adds PSRAM to the heap
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# allocator, so large allocations (Box, Rope, libgit2 buffers) land there
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# instead of the ~339 KB internal DRAM Spike 6 measured. Octal PSRAM occupies
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# GPIO 33–37; the EPD/SD pins (4–13) deliberately avoid that range, so no wiring
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# conflict. Speed left at the 40 MHz default (safe first-enable; 80 MHz needs
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# matching flash-freq config and is a later tuning step).
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CONFIG_SPIRAM=y
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CONFIG_SPIRAM_MODE_OCT=y
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CONFIG_SPIRAM_USE_MALLOC=y
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# FatFS fast seek (sync-latency root cause, 2026-07-12). Without it, lseek
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# resolves by walking the file's FAT cluster chain over SPI — forward from the
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# current position, from the CHAIN HEAD on any backward seek. sd_bench measured
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# ~190 ms per long seek into the 263 MB packfile (5.8 ms at offset 0), and
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# libgit2 pays ~8 such seeks per loose-object write via p_mmap's lseek+read →
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# the ~1.5 s/object commit cost (docs/tradeoff-curves/sync-commit-staging.md).
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# Fast seek builds an in-memory cluster-link map (CLMT) per READ-mode file,
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# making lseek O(1); write-mode files transparently fall back to the walk. The
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# buffer is per-open-file, 4 B × size: 256 words = 1 KB, covering ~127 fragments
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# (the default 64 covers ~31 — a freshly-provisioned pack is near-contiguous,
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# but don't let card aging silently disable the fix; vfs_fat falls back to slow
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# seeks when the map doesn't fit).
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CONFIG_FATFS_USE_FASTSEEK=y
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CONFIG_FATFS_FAST_SEEK_BUFFER_SIZE=256
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# Silence the legacy-I2C boot warning. esp-idf-hal's i2c.rs is always compiled
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# and binds the old `driver/i2c.h` API, so the legacy driver's TU (and its
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# `__attribute__((constructor))` deprecation warning) gets linked into every
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# image — even though Typoena uses no I2C at all (EPD/SD are SPI, keyboard is
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# USB). This flag wraps that constructor out. Safe here: we link neither the
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# new i2c_master driver nor call the old one, so the conflict-abort check it
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# also removes can never fire.
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CONFIG_I2C_SKIP_LEGACY_CONFLICT_CHECK=y
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# TLS trust store (Spike 6 — Wi-Fi + TLS, the gate for Spike 7 git push).
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# The certificate bundle backs esp_crt_bundle_attach so an HTTPS GET to
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# api.github.com validates against real roots. FULL rather than the common
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# subset so a less common CA in the chain can't surprise us on the bench.
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CONFIG_MBEDTLS_CERTIFICATE_BUNDLE=y
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CONFIG_MBEDTLS_CERTIFICATE_BUNDLE_DEFAULT_FULL=y
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