On-device [PERF] capture decomposed the remaining ~1s tap latency:
each uncached conversation costs one SPI-LittleFS metadata read
(~230ms). Repeat taps still paid 2 perpetual fallbacks (empty-
content tails never got cached), and the first tap after every
boot paid all 9 (the in-memory repop was never committed to the
index).
- bump microLXMF pin c8d3156 -> 6bea23c (feat/conversation-
preview-cache): preview_valid index flag so 'cached empty'
differs from 'unpopulated'; bounded preview copy (the old
strncpy read past the non-terminated content Bytes); public
commit_index().
- refresh() re-pops empty-content tails as a valid cached
preview and arms a one-shot deferred index commit;
UIManager::update() drains it out-of-lock (flush_pending_
index_commit, between drops and mark-read) so the warmed
previews persist and the next cold boot reads them from the
index.
- fix the [PERF] skip-log total= wrap (printed p_t_diff - p_t0,
a uint32 underflow; total was already p_t_diff).
[PERF] instrumentation stays in this commit (temporary,
marked); it is removed before merge once the fix is validated
on-device.
refresh() previously opened + parsed each conversation's newest message
file (load_message_metadata) on every list refresh, which dominated
list-load time on SPI LittleFS. It now reads the per-conversation
last-message preview + timestamp from the store's in-memory index
(O(1), zero I/O) and falls back to load_message_metadata only when the
index has no cached preview — the first refresh after a firmware
upgrade or after a corrupt-tail drop — then writes the preview back
through so the fallback happens at most once per conversation per
firmware generation. The write-through is skipped when drops were
queued (the drained deletes move the tail, so a preview written for the
old tail would be stale for one refresh).
Host benchmark (x86 + POSIX fs, 24 msgs/conv): the per-conversation
store-load work drops from ~0.149ms (9 convs) / ~0.342ms (20 convs) to
~0.002ms / ~0.005ms, and the cold-boot path (store reconstructed from
disk) matches the warm path because the preview now persists in the
index.
Bumps the microLXMF pin to c8d3156 (feat/conversation-preview-cache)
in platformio.ini, the release audit, and the native reference test.
Adds tests/microlxmf/bench_conversation_list_load.cpp (baseline vs
index warm/cold) and the bench target in tests/microlxmf/CMakeLists.txt.
Pike