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- SaveActiveSessionsToDisk: 2s debounce timer coalesces rapid saves - SaveOrganization: 2s debounce timer (called from 12+ places) - SaveUiState: 1s debounce with pending state object - ReconcileOrganization: skip if session set unchanged (hash check) - GetOrganizedSessions: cached result invalidated by hash key - Markdown cache: use string key (no hash collisions), LRU eviction at 1000 Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
RefreshState was prematurely clearing _sessionSwitching before SafeRefreshAsync could read it, causing the expensive JS draft capture round-trip to execute during every session switch. Before: 729-4027ms per switch After: 16-28ms per switch (50-150x improvement) Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
LoadPersistedSessions() was called from RefreshSessions() on every OnStateChanged event, scanning all session directories for resumable sessions. This scans workspace.yaml + events.jsonl for each dir. Now only loads persisted sessions on init and when the section is explicitly toggled open. Reduces steady-state I/O dramatically. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Two new domain knowledge skills for future agents: - performance-optimization: 5 critical invariants (session switching, debounce flush, LoadPersistedSessions danger, cache invalidation, ReconcileOrganization skip guard), caching architecture, known optimization opportunities - processing-state-safety: 9-item cleanup checklist, 8 IsProcessing paths table, 8 invariants, top 3 regression patterns, reference to full regression history across 7 PRs Also adds brief performance pointers to copilot-instructions.md with links to the skills for detailed reference. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Tests cover: - GetOrganizedSessions caching (same instance when unchanged) - Cache invalidation on group add, sort mode change, group delete - Organization operations (create, delete, move, pin, collapse) - SaveUiState rapid-fire without corruption - DisposeAsync safety (flush + idempotent) - GetOrganizedSessions returns IReadOnlyList 836 total tests passing (822 existing + 14 new) Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
- LoadUiState returns pending debounced state instead of stale disk data - DisposeAsync flushes pending UI state (was only disposing timer) - SaveOrganization invalidates organized sessions cache immediately - ReconcileOrganization hash is now order-independent (XOR) - Added 6 edge case tests (842 total passing) Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
- Snapshot JSON/entries on caller's thread before passing to Timer callback, preventing concurrent mutation of Organization lists and session History - Add IsRestoring guard to FlushSaveActiveSessionsToDisk (prevents partial writes during app startup if dispose is called mid-restore) - Replace XOR hash with additive hash in ReconcileOrganization (fewer collisions) - Remove Task.Run wrappers from SaveUiState calls (no longer needed since SaveUiState is now in-memory + debounce timer, eliminates read-modify-write race) Findings from: Opus 4.6, Codex 5.3, Sonnet 4.6 code reviews Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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- SaveOrganization snapshot-on-caller doesn't throw under rapid mutations - SaveOrganization state is captured before timer fires - FlushSaveActiveSessionsToDisk respects IsRestoring during dispose - ReconcileOrganization hash handles group create/delete churn - SaveUiState is non-blocking (<500ms for 100 calls, returns latest state) - Rapid group mutations don't corrupt organization state - 883 total tests passing (26 in PerformanceOptimizationTests) Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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Problem
Mac Catalyst was very slow when:
[SwitchPerf]logs)Fast on Android/Windows and for new users — the issue scaled with accumulated data (753 session dirs, 463MB events.jsonl).
Root Causes Found & Fixed
1. JS draft capture running during every session switch (biggest impact)
_sessionSwitchingflag was cleared prematurely inRefreshState()beforeSafeRefreshAsync()could read it. This caused an expensive round-trip JS interop call (querying all card inputs, capturing draft text, focus, cursor position) to execute on every single session switch.Before: 729–4027ms per switch | After: 16–28ms (50-150x faster)
2. Synchronous disk I/O on every state change
SaveActiveSessionsToDisk(): sync read + merge + write ofactive-sessions.jsoncalled 7+ times per operationSaveOrganization(): sync write called from 12+ locationsSaveUiState(): sync read-modify-write on UI threadFix: Timer-based debounce (2s for sessions/org, 1s for UI state) coalesces rapid saves. Flush on dispose.
3.
GetOrganizedSessions()recalculated on every renderCreated dictionaries, iterated all sessions per group, sorted — on every
StateHasChanged().Fix: Cache with hash-key invalidation (session count + group count + sort mode + per-session state).
4.
LoadPersistedSessions()scanning 753 directories on every state changeRefreshSessions()calledGetPersistedSessions()which readsworkspace.yaml+events.jsonlfrom every session directory.Fix: Only load persisted sessions on init and when the section is explicitly toggled open.
5. Markdown cache hash collisions + no eviction
Used
GetHashCode()as key (collision risk). Capped at 500 with no eviction.Fix: String content as key, LRU eviction at 1000 entries.
6.
ReconcileOrganization()running unnecessarilyFull reconciliation (disk reads, directory checks) ran after every session operation even when nothing changed.
Fix: Hash-based skip when session set unchanged.
Test Results