Performance, reliability, and observability improvements for NativeLink

Major changes:

- MokaEvictingMap: lock-free TinyLFU cache replacing Mutex+LRU EvictingMap,
  migrated FilesystemStore, scheduler, ExistenceCacheStore, and MemoryStore

- Streaming blob pipeline: StreamingBlob primitive for concurrent
  read-while-write with sliding window, InFlightBlobMap, Phase 1 complete

- io_uring integration: fork of tokio-epoll-uring with metadata ops
  (linkat, renameat, mkdirat, unlinkat, symlinkat), hybrid I/O mode

- QUIC transport: BBR congestion, jumbo MTU discovery, connection pooling,
  TLS support, dual TCP+QUIC transport with automatic fallback

- Server graceful shutdown: HTTP/2 GOAWAY drain, QUIC shutdown, flush
  writes, scheduler drain with configurable timeouts

- Worker improvements: blob mirroring, worker proxy store, peer sharing,
  locality-aware scheduling, prefetch, directory cache optimizations

- Store optimizations: scatter-gather MemoryStore, zero-copy ByteStream
  read/write codecs, batch operations, write dedup with in-flight
  coalescing, parallel BFS tree resolution

- Observability: pprof CPU profiling, stall detector with stack dumps,
  comprehensive write path and eviction logging, action lifecycle logging

- GetTree improvements: subtree caching, coalescing concurrent requests,
  batch ExistenceCache insert, Arc zero-copy cache entries

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: rejuvenile

.cargo/config.toml

@@ -0,0 +1,9 @@
+[build]
+rustflags = ["-C", "target-cpu=native", "-C", "force-frame-pointers=yes", "--cfg", "tokio_unstable"]
+
+[target.x86_64-unknown-linux-gnu]
+rustflags = ["-C", "target-cpu=native", "-C", "link-arg=-fuse-ld=mold", "-C", "force-frame-pointers=yes", "--cfg", "tokio_unstable"]
+
+[profile.release]
+lto = "thin"
+codegen-units = 8

.gitignore

@@ -26,3 +26,4 @@ nativelink.bazelrc
 buck-out/
 nativelink_config.schema.json
 .cargo/config.toml
+.cargo/config.toml

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "tokio-epoll-uring"]
+	path = tokio-epoll-uring
+	url = forgejo@optimus.m0n0.space:rejuvenile/tokio-epoll-uring.git

CLAUDE.md

@@ -53,5 +53,44 @@
 - `#[cfg(target_os = "...")]` for OS-specific code (Linux vs macOS)
 
 ## Tests
+- **Test-first development**: when implementing any new feature, write tests first
+  (unit, integration, and cross-component interaction tests). Verify they fail before
+  implementing the feature, then make them pass. Include fakes/mocks for
+  hardware-interaction tests where needed.
+- **Bug fixes require a failing test first**: when fixing a bug, write a test that
+  reproduces the failure, verify it fails, then implement the fix and show the test
+  passes. Never fix a bug without a regression test.
 - Integration tests in `tests/` directory; minimal inline `#[cfg(test)]` modules
 - Use `nativelink-macro` test harness (`#[nativelink_test]`)
+
+## Change Process
+- **Chesterton's Fence**: before modifying or removing any behavior, always check
+  `git log`, `git blame`, and `git log -S` to understand *why* the code exists.
+  If a commit message or comment explains the reason, evaluate whether that reason
+  still applies before making the change.
+
+## Code Review
+- **Before committing any change**, send the changes to a code review agent and a
+  performance review agent. Work to obtain their sign-off before committing. Fix
+  any issues they identify. Only commit after both reviews pass with no blocking
+  issues.
+
+## Git Journal
+- **Journal all git operations**: append every `git commit`, `git push`, `git revert`,
+  `git stash`, and any other state-changing git command to `.claude/git-journal.md`
+  in the working directory. Each entry should include the timestamp, command, and a
+  one-line description. This prevents losing track of what was done across context
+  compressions.
+
+## Working Directory Discipline
+- **Always verify `pwd` before git operations.** Agent worktrees (`.claude/worktrees/`)
+  have separate git branches. Commits in a worktree do NOT go to `main`. The Bash tool
+  may silently `cd` into a worktree after an agent runs. Always `cd /path/to/nativelink`
+  before any `git commit`, `git push`, or `git status`.
+- **Never use `git stash pop`** — it can cause merge conflicts that `git checkout --` resolves
+  by reverting uncommitted edits. Use `git stash apply` + `git stash drop` separately.
+- **Commit early, commit often.** After each logical change compiles, commit immediately.
+  Don't accumulate multiple uncommitted changes across a session — context compression
+  or worktree confusion can lose them.
+- **After editing files, verify with `git diff --stat HEAD`** that the expected changes
+  appear before moving on to the next task.