# Windows and WSL Performance Tracker Last verified: 2026-08-08 This document is the durable queue for Windows performance work. The umbrella issue is [#9300](https://github.com/stablyai/orca/issues/9300). Keep fixes measurement-first: add a deterministic reproduction, record median and p95 where timing matters, verify correctness as well as latency, and preserve native Windows, WSL, SSH, folder-workspace, and mixed-version behavior. ## Status at a glance | Priority | Area | Tracking | Status | Next action | | -------- | -------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------ | ------------------------------------------------------------------------------------------------------------------- | | P0 | WSL Git status and staging latency | [#9284](https://github.com/stablyai/orca/issues/9284), [#9768](https://github.com/stablyai/orca/issues/9768), [PR #13207](https://github.com/stablyai/orca/pull/13207) | Fix PR open | Land the measured shell-startup fix, then investigate DrvFS routing and linked-gitdir compatibility separately. | | P1 | Cross-cutting Windows/WSL measurements | [#9300](https://github.com/stablyai/orca/issues/9300), [PR #11261](https://github.com/stablyai/orca/pull/11261) | Open | Establish the baseline matrix below and use interleaved comparisons for startup changes. | | P1 | Clipboard staging-directory ownership | [#12835](https://github.com/stablyai/orca/issues/12835), [PR #12917](https://github.com/stablyai/orca/pull/12917) | Fix merged; design follow-up unfiled | Move new staging files under one Orca-owned parent so cleanup never enumerates the shared temp root. | | P1 | WSL hook-relay startup reconciliation | [#12900](https://github.com/stablyai/orca/issues/12900), [PR #13139](https://github.com/stablyai/orca/pull/13139) | Fix merged; design follow-up unfiled | Reconcile relays once from the live daemon-session inventory after the hook server starts. | | P2 | Main-process child-spawn audit | [#11161](https://github.com/stablyai/orca/issues/11161), [PR #12217](https://github.com/stablyai/orca/pull/12217), [PR #11698](https://github.com/stablyai/orca/pull/11698) | Known triggers fixed; audit remains | Find remaining startup or periodic main-process spawns and measure event-loop gaps under injected spawn delay. | | P2 | Reverted accumulator protections | [PR #10179](https://github.com/stablyai/orca/pull/10179), [PR #10255](https://github.com/stablyai/orca/pull/10255) | Unscoped | Audit current hot paths individually; file only narrow issues with a present-day deterministic reproduction. | | Monitor | General embedded-TUI lag | [#12446](https://github.com/stablyai/orca/issues/12446) | Closed as fixed | Reopen only with an exact version, agent, local/remote runtime, and captured frame/event-loop metrics. | Environment requirements: - Real WSL required: Git hot-path benchmarking and hook-relay startup reconciliation. - Native Windows sufficient: clipboard parent migration, blocking-spawn fault injection, capability probing, and startup measurements. - Platform-independent unit work is not a substitute for real Windows/WSL latency evidence where a subprocess or filesystem boundary is the suspected cause. ## Completed fixes and evidence ### Port scanning under slow process creation - Issue [#11161](https://github.com/stablyai/orca/issues/11161), fixed by [PR #12217](https://github.com/stablyai/orca/pull/12217). - Endpoint-security software could delay `CreateProcessW`; even asynchronous Node process APIs perform process creation on the caller, freezing Electron's main event loop. - Port-scan commands moved to a worker, command deadlines now begin after process creation, and the tests inject a real delayed spawn to pin UI responsiveness and false-timeout behavior. ### Repeated WSL and PowerShell capability probes - Fixed by [PR #11698](https://github.com/stablyai/orca/pull/11698), merge commit `c3bf22b9a8`. - Repeated synchronous `wsl.exe` and `pwsh.exe` probes could pause the main loop every 30 seconds. - Capability reads are asynchronous and share one bounded 30 s → 60 s → 120 s backoff, followed by a five-minute ceiling check. A stable no-WSL session drops from 60 checks per consumer in 30 minutes to at most nine shared reads. - Native Windows ABBA results: | Command | Synchronous median / p95 event-loop gap | Asynchronous median / p95 gap | | ------------------------ | --------------------------------------: | ----------------------------: | | `wsl.exe --status` | 34.1 / 63.5 ms | 16.1 / 16.4 ms | | `wsl.exe --list --quiet` | 35.1 / 37.3 ms | 16.0 / 25.5 ms | | `pwsh.exe -Version` | 103.0 / 312.9 ms | 18.9 / 25.8 ms | ### Startup hang while cleaning remote clipboard files - Issue [#12835](https://github.com/stablyai/orca/issues/12835), fixed by [PR #12917](https://github.com/stablyai/orca/pull/12917), merge commit `595097b5fc`. - A temp root with 1,232,261 entries produced approximately 1.23 million promises on the main process, causing a V8 microtask and garbage-collection storm. - Cleanup now streams with `opendir`, filters foreign entries before scheduling work, and caps removals at eight. A native Windows Electron run remained responsive with 100,000 unrelated entries. ### Slow Codex hooks after Orca restart - Issue [#12900](https://github.com/stablyai/orca/issues/12900), fixed by [PR #13139](https://github.com/stablyai/orca/pull/13139), merge commit `982570648a`. - Daemon-backed WSL Codex sessions survived an Orca restart while their stable endpoint file retained the old main-process port and token. Each tool call could pay two stale-hook fallbacks. - A local WSL PTY reattach now ensures the relay for the daemon-reported original distro. Native, fresh, SSH, blank, and unknown-distro cases are no-ops; the manager deduplicates per distro. - Real Windows/WSL2 benchmark, using the generated Codex hook and production relay: | Phase | Samples | Median | p95 | Delivery | | --------------------- | ------: | ---------: | ---------: | ----------------: | | Stale endpoint | 20 | 1,636.0 ms | 1,639.1 ms | timeout/fail-open | | Refreshed on reattach | 20 | 58.5 ms | 61.9 ms | 20/20 | ### WSL login-shell overhead on Git reads - Issues [#9284](https://github.com/stablyai/orca/issues/9284) and [#9768](https://github.com/stablyai/orca/issues/9768), addressed by open [PR #13207](https://github.com/stablyai/orca/pull/13207). - WSL source-control reads repeatedly started a login shell. Slow profile scripts and banner output added latency and could contaminate Git's machine-readable output. - The first read retains the login-shell behavior while a background per-distro probe captures Git's absolute path and `PATH`. Later status, numstat, and upstream/config reads execute directly. Mutations, network operations, SSH, relay, native Git, and risky profile environments stay on the existing path. - Real Windows 11/WSL2 ABBA results, with 3 warmups and 20 samples per natural-profile pair: | Operation | Login median / p95 | Direct median / p95 | | ---------------------------- | -----------------: | ------------------: | | WSL-filesystem status | 73.2 / 75.7 ms | 63.5 / 66.8 ms | | WSL-filesystem stage+refresh | 221.1 / 234.8 ms | 203.3 / 207.0 ms | | DrvFS status | 1,063.2 / 1,134.4 ms | 1,030.8 / 1,070.5 ms | | DrvFS stage+refresh | 1,272.7 / 1,318.8 ms | 1,225.3 / 1,246.4 ms | - With a deterministic 250 ms login-profile delay, 2 warmups and 10 samples, native status fell from 330.1 / 339.4 ms median / p95 to 64.5 / 67.7 ms. Every benchmark pair produced byte-identical Git payloads. The profile also emitted 106 bytes of non-Git banner text per login-shell invocation. ## Next investigation: WSL filesystem-host routing PR #13207 removes avoidable shell startup but does not address the dominant cost for repositories on `C:\`: Git traversing the tree through WSL's DrvFS mount. In the same fixture, Windows Git completed status in 22.4 ms median versus approximately 1,031 ms through WSL/DrvFS. Investigate whether read-only source-control operations should follow the filesystem host instead of the selected terminal runtime. First prove equivalent status semantics across Git configuration, autocrlf, symlinks, hooks, credentials, case behavior, worktree metadata, SSH/folder workspaces, and Git 2.25. Do not route mutations or network operations until their environment contract is independently established. Windows-created linked worktrees need a separate compatibility design: their `.git` files can contain a `C:/.../.git/worktrees/...` gitdir that WSL Git cannot resolve. Path translation must be scoped to metadata owned by the routed repository and must not rewrite arbitrary Git output. ## Architectural follow-ups ### Own the clipboard staging parent PR #12917 makes shared-temp enumeration memory-safe, but enumeration time is still proportional to every other application's temp entries. New transfers should use a structure such as: ```text /orca-clipboard-files//... ``` Cleanup could then enumerate only Orca-owned children. Preserve a bounded compatibility sweep for legacy top-level `orca-clipboard-file-*` directories, prove symlink and path containment, and benchmark against a large foreign temp root before removing legacy handling. ### Reconcile WSL hook relays at startup PR #13139 repairs the relay when one of today's PTY reattach paths runs. The desired-state design is: 1. Start the new main-process hook server. 2. Read the daemon's live local session inventory. 3. Group authoritative non-null WSL owners by distro. 4. Ensure and observe one relay per live distro. 5. Retain reattach-time ensure as a safety net for later sessions. Only live sessions should participate; cold history or stale metadata must not boot a stopped distro. Cover multiple panes in one distro, multiple distros, old daemons without WSL metadata, immediate hook traffic, relay failure, and startup ordering. ### Continue the blocking-spawn audit PRs #12217 and #11698 removed two proven main-thread freeze sources, not the entire failure class. Audit main-process `spawnSync`/`execFileSync` calls and periodic asynchronous spawns whose process creation still runs on the main thread. Prioritize startup, focus, polling, watcher, Git, and terminal-open paths. Use an injected process-creation delay and event-loop-gap measurement; do not infer responsiveness from command completion time alone. ## Measurement backlog The baseline requested by [#9300](https://github.com/stablyai/orca/issues/9300) is still incomplete: - open worktree → first useful Git status; - idle child-process spawns per minute; - watcher installation during a worktree switch; - quick-open and search in a medium repository; - PTY spawn, separated into process creation, environment/probe work, and first usable prompt; - native `C:\` repo, WSL-filesystem repo, and `C:\` repo using a WSL project runtime; - Defender/default endpoint security and a controlled excluded-worktree comparison. [PR #11261](https://github.com/stablyai/orca/pull/11261) provides an open interleaved startup benchmark with drift controls. [PR #11262](https://github.com/stablyai/orca/pull/11262) is a useful caution: its bundle-size change did not show the initially suspected seconds-scale startup improvement once measured interleaved. Do not quote blocked before/after startup medians when the machine itself can drift. ## Triage rules - Attach an exact Orca version, Windows build, repository location, selected project runtime, and agent. - Separate UI event-loop stalls from a command that is merely slow in the background. - Prefer deterministic fault injection for hangs and interleaved samples for performance comparisons. - Report median, p95, failures/timeouts, and correctness; a faster wrong result is not a win. - Keep broad audits in #9300, but give every actionable root cause its own issue and narrowly scoped PR. - Avoid another repository-wide performance or memory mega-PR. #10179 contained useful protections, but its 1,626-file scope was reverted by #10255; re-land measured fixes independently with focused tests.