mirror of
https://github.com/oven-sh/bun
synced 2026-02-10 02:48:50 +00:00
## Summary Implements a string fast path optimization for `postMessage` and `structuredClone` operations that provides significant performance improvements for string-only data transfer, along with various bug fixes and infrastructure improvements. ## Key Performance Improvements **postMessage with Workers:** - **Small strings (11 chars):** ~5% faster (572ns vs 599ns) - **Medium strings (14KB):** **~2.7x faster** (528ns vs 1.40μs) - **Large strings (3MB):** **~660x faster** (540ns vs 356μs) **Compared to Node.js postMessage:** - Similar performance for small strings - Competitive for medium strings - **~455x faster** for large strings (540ns vs 245μs) ## Implementation Details The optimization adds a **string fast path** that bypasses full structured cloning serialization when: - Input is a pure string (`value.isString()`) - No transfer list or message ports are involved - Not being stored persistently ### Core Changes **String Thread-Safety Utilities (`BunString.cpp/h`):** - `isCrossThreadShareable()` - Checks if string can be safely shared across threads - `toCrossThreadShareable()` - Converts strings to thread-safe form via `isolatedCopy()` - Handles edge cases: atoms, symbols, substring slices, external buffers **Serialization Fast Path (`SerializedScriptValue.cpp`):** - New `m_fastPathString` field stores string data directly - Bypasses full object serialization machinery for pure strings - Creates isolated copies for cross-thread safety **Deserialization Fast Path:** - Directly returns JSString from stored string data - Avoids parsing serialized byte streams **Updated Flags System (`JSValue.zig`, `Serialization.cpp`):** - Replaces boolean `forTransfer` with structured `SerializedFlags` - Supports `forCrossProcessTransfer` and `forStorage` distinctions **Structured Clone Infrastructure:** - Moved `structuredClone` implementation to dedicated `StructuredClone.cpp` - Added `jsFunctionStructuredCloneAdvanced` for testing with custom flags - Improved class serialization compatibility checks (`isForTransfer`, `isForStorage`) **IPC Improvements (`ipc.zig`):** - Fixed race conditions in `SendQueue` by deferring cleanup to next tick - Proper fd ownership handling with `bun.take()` - Cached IPC serialize/parse functions for better performance **BlockList Thread Safety Fixes (`BlockList.zig`):** - Fixed potential deadlocks by moving mutex locking inside methods - Added atomic `estimated_size` counter to avoid lock during GC - Corrected pointer handling in comparison functions - Improved GC safety in `rules()` method ## Benchmark Results ``` ❯ bun-21926 bench/string-postmessage.mjs # This branch postMessage(11 chars string) 572.24 ns/iter postMessage(14 KB string) 527.55 ns/iter ← ~2.7x faster postMessage(3 MB string) 539.70 ns/iter ← ~660x faster ❯ bun-1.2.20 bench/string-postmessage.mjs # Previous postMessage(11 chars string) 598.76 ns/iter postMessage(14 KB string) 1.40 µs/iter postMessage(3 MB string) 356.38 µs/iter ❯ node bench/string-postmessage.mjs # Node.js comparison postMessage(11 chars string) 569.63 ns/iter postMessage(14 KB string) 1.46 µs/iter postMessage(3 MB string) 245.46 µs/iter ``` **Key insight:** The fast path achieves **constant time performance** regardless of string size (~540ns), while traditional serialization scales linearly with data size. ## Test Coverage **New Tests:** - `test/js/web/structured-clone-fastpath.test.ts` - Fast path memory usage validation - `test/js/web/workers/structuredClone-classes.test.ts` - Comprehensive class serialization tests - Tests ArrayBuffer transferability - Tests BunFile cloning with storage/transfer restrictions - Tests net.BlockList cloning behavior - Validates different serialization contexts (default, worker, window) **Enhanced Tests:** - `test/js/web/workers/structured-clone.test.ts` - Multi-function testing - Tests `structuredClone`, `jscSerializeRoundtrip`, and cross-process serialization - Validates consistency across different serialization paths - `test/js/node/cluster.test.ts` - Better error handling and debugging **Benchmarks:** - `bench/string-postmessage.mjs` - Worker postMessage performance comparison - `bench/string-fastpath.mjs` - Fast path vs traditional serialization comparison ## Bug Fixes **BlockList Threading Issues:** - Fixed potential deadlocks when multiple threads access BlockList simultaneously - Moved mutex locks inside methods rather than holding across entire function calls - Added atomic size tracking for GC compatibility - Fixed comparison function pointer handling **IPC Race Conditions:** - Fixed race condition where `SendQueue._onAfterIPCClosed()` could be called on wrong thread - Deferred cleanup operations to next tick using task queue - Improved file descriptor ownership with proper `bun.take()` usage **Structured Clone Compatibility:** - Enhanced class serialization with proper transfer/storage mode checking - Fixed edge cases where non-transferable objects were incorrectly handled - Added better error reporting for unsupported clone operations ## Technical Notes - Thread safety ensured via `String.isolatedCopy()` for cross-VM transfers - Memory cost calculation updated to account for string references - Maintains full compatibility with existing structured clone semantics - Does not affect object serialization or transfer lists - Proper cleanup and error handling throughout IPC pipeline --------- Co-authored-by: Jarred Sumner <jarred@jarredsumner.com> Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com> Co-authored-by: Meghan Denny <meghan@bun.sh>
102 lines
3.1 KiB
CMake
102 lines
3.1 KiB
CMake
option(WEBKIT_VERSION "The version of WebKit to use")
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option(WEBKIT_LOCAL "If a local version of WebKit should be used instead of downloading")
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if(NOT WEBKIT_VERSION)
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set(WEBKIT_VERSION 53385bda2d2270223ac66f7b021a4aec3dd6df75)
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endif()
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string(SUBSTRING ${WEBKIT_VERSION} 0 16 WEBKIT_VERSION_PREFIX)
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if(WEBKIT_LOCAL)
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set(DEFAULT_WEBKIT_PATH ${VENDOR_PATH}/WebKit/WebKitBuild/${CMAKE_BUILD_TYPE})
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else()
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set(DEFAULT_WEBKIT_PATH ${CACHE_PATH}/webkit-${WEBKIT_VERSION_PREFIX})
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endif()
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option(WEBKIT_PATH "The path to the WebKit directory")
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if(NOT WEBKIT_PATH)
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set(WEBKIT_PATH ${DEFAULT_WEBKIT_PATH})
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endif()
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set(WEBKIT_INCLUDE_PATH ${WEBKIT_PATH}/include)
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set(WEBKIT_LIB_PATH ${WEBKIT_PATH}/lib)
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if(WEBKIT_LOCAL)
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if(EXISTS ${WEBKIT_PATH}/cmakeconfig.h)
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# You may need to run:
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# make jsc-compile-debug jsc-copy-headers
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include_directories(
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${WEBKIT_PATH}
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${WEBKIT_PATH}/JavaScriptCore/Headers/JavaScriptCore
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${WEBKIT_PATH}/JavaScriptCore/PrivateHeaders
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${WEBKIT_PATH}/bmalloc/Headers
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${WEBKIT_PATH}/WTF/Headers
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${WEBKIT_PATH}/JavaScriptCore/DerivedSources/inspector
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${WEBKIT_PATH}/JavaScriptCore/PrivateHeaders/JavaScriptCore
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)
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endif()
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# After this point, only prebuilt WebKit is supported
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return()
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endif()
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if(WIN32)
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set(WEBKIT_OS "windows")
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elseif(APPLE)
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set(WEBKIT_OS "macos")
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elseif(UNIX)
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set(WEBKIT_OS "linux")
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else()
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message(FATAL_ERROR "Unsupported operating system: ${CMAKE_SYSTEM_NAME}")
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endif()
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if(CMAKE_SYSTEM_PROCESSOR MATCHES "arm64|aarch64")
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set(WEBKIT_ARCH "arm64")
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elseif(CMAKE_SYSTEM_PROCESSOR MATCHES "amd64|x86_64|x64|AMD64")
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set(WEBKIT_ARCH "amd64")
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else()
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message(FATAL_ERROR "Unsupported architecture: ${CMAKE_SYSTEM_PROCESSOR}")
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endif()
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if(LINUX AND ABI STREQUAL "musl")
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set(WEBKIT_SUFFIX "-musl")
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endif()
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if(DEBUG)
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set(WEBKIT_SUFFIX "${WEBKIT_SUFFIX}-debug")
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elseif(ENABLE_LTO)
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set(WEBKIT_SUFFIX "${WEBKIT_SUFFIX}-lto")
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else()
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set(WEBKIT_SUFFIX "${WEBKIT_SUFFIX}")
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endif()
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if(ENABLE_ASAN)
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# We cannot mix and match ASan Bun + non-ASan WebKit, or vice versa, because some WebKit classes
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# change their layout according to whether ASan is used, for example:
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# https://github.com/oven-sh/WebKit/blob/eda8b0fb4fb1aa23db9c2b00933df8b58bcdd289/Source/WTF/wtf/Vector.h#L682
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set(WEBKIT_SUFFIX "${WEBKIT_SUFFIX}-asan")
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endif()
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setx(WEBKIT_NAME bun-webkit-${WEBKIT_OS}-${WEBKIT_ARCH}${WEBKIT_SUFFIX})
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set(WEBKIT_FILENAME ${WEBKIT_NAME}.tar.gz)
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setx(WEBKIT_DOWNLOAD_URL https://github.com/oven-sh/WebKit/releases/download/autobuild-${WEBKIT_VERSION}/${WEBKIT_FILENAME})
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if(EXISTS ${WEBKIT_PATH}/package.json)
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file(READ ${WEBKIT_PATH}/package.json WEBKIT_PACKAGE_JSON)
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if(WEBKIT_PACKAGE_JSON MATCHES ${WEBKIT_VERSION})
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return()
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endif()
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endif()
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file(DOWNLOAD ${WEBKIT_DOWNLOAD_URL} ${CACHE_PATH}/${WEBKIT_FILENAME} SHOW_PROGRESS)
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file(ARCHIVE_EXTRACT INPUT ${CACHE_PATH}/${WEBKIT_FILENAME} DESTINATION ${CACHE_PATH} TOUCH)
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file(REMOVE ${CACHE_PATH}/${WEBKIT_FILENAME})
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file(REMOVE_RECURSE ${WEBKIT_PATH})
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file(RENAME ${CACHE_PATH}/bun-webkit ${WEBKIT_PATH})
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if(APPLE)
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file(REMOVE_RECURSE ${WEBKIT_INCLUDE_PATH}/unicode)
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endif()
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