June 2026 performance and technical summary: Key features delivered: - folly: Implemented coroutine-enabled TimedMutex with co_lock() and co_scoped_lock() to enable fiber and coroutine callers to contend on the same mutex. Includes cancellation support and timed acquisition, aligning with co-operative locking semantics and enabling co_await paths. Commit: 8aafa6c733075506e00ab0ab02986971b83db442. Also introduced benchmark coverage comparing lock() vs co_lock() across thread, fiber, and coroutine configurations. - CacheLib: Added coroutine-compatible locking in the MultiWrite path via coLock/plumbing (co_lock, coGrabUpdateLocks, coLockOid, LockMap::co_lock, etc.). Committed as part of D103217162 integration with commit 41e27bb6d27a418138064311a555ebc7fb94996e. This enables the coroutine path to yield during lock access and use timeoutNoDiscard() to avoid leaks. Major bugs fixed (interop and safety): - Resolved interop gaps between fiber and coroutine locking in TimedMutex, preventing OS-thread blocking for coroutine callers and reducing race conditions during lock/unlock across paradigms (via co_lock/co_scoped_lock and cancellation paths). - Improved safety around timeout handling: using timeoutNoDiscard() in coroutine lock acquisition to ensure locks are not leaked when timeouts occur. - Extended coroutine-safe locking across CacheLib’s MultiWrite path, eliminating potential contention-induced deadlocks and improving reliability under high-concurrency workloads. Overall impact and accomplishments: - Substantial performance and scalability gains in high-concurrency scenarios, with coroutines yielding during lock contention and fibers sharing the same locking primitives. Business value includes higher throughput for distributed write operations and reduced latency under contention, plus safer, more maintainable code paths across fiber/coroutine boundaries. Technologies/skills demonstrated: - C++ coroutines and fibers interoperability (folly::fibers and folly::coro paths), co_lock/co_scoped_lock usage, cancellation handling, and timeout semantics (timeoutNoDiscard). - Advanced locking primitives, TAO/LockMap integration, and cross-repo coordination to enable coroutine-enabled locking in a large-scale codebase.