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child_process: serialize advanced IPC messages natively
The `advanced` IPC serialization codec was implemented in JavaScript (ChildProcessSerializer / ChildProcessDeserializer in lib/internal/child_process/serialization.js). It allocated a wrapper serializer/deserializer per message and crossed the JS/C++ boundary several times for every message (writeHeader, writeValue, releaseBuffer, readHeader, readValue and friends). Move the codec into a native `ipc_serdes` binding that drives the V8 ValueSerializer/ValueDeserializer with a C++ delegate. The wire format is preserved byte-for-byte: a big-endian uint32 length prefix followed by the V8 payload, with ArrayBufferViews tagged as host objects so that Node Buffers round-trip as Buffers rather than plain Uint8Arrays. The JSON codec is left unchanged. A cctest (test/cctest/test_node_ipc_serdes.cc) exercises the binding directly, covering round-trips of primitives, objects, typed arrays and Buffers (including the Buffer-vs-Uint8Array distinction) and asserting the big-endian length-prefix framing. Round-trip throughput (benchmark/child_process/child-process-ipc-roundtrip): payload before after change 64 B ~300k/s ~800k/s +166% 1 KiB ~272k/s ~616k/s +126% 16 KiB ~91k/s ~120k/s +32% 64 KiB ~30k/s ~35k/s +16% The gain is largest for small messages, where per-message JavaScript overhead dominated, and tapers for large messages, where the actual serialization (already native) dominates. Signed-off-by: Yagiz Nizipli <yagiz@nizipli.com>
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9 files changed

Lines changed: 712 additions & 50 deletions

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‎lib/internal/child_process/serialization.js‎

Lines changed: 5 additions & 50 deletions
Original file line numberDiff line numberDiff line change
@@ -10,43 +10,14 @@ const {
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} = primordials;
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const { Buffer } = require('buffer');
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const { StringDecoder } = require('string_decoder');
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const v8 = require('v8');
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const { isArrayBufferView } = require('internal/util/types');
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const assert = require('internal/assert');
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const { serialize, deserialize } = internalBinding('ipc_serdes');
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const { streamBaseState, kLastWriteWasAsync } = internalBinding('stream_wrap');
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const kMessageBuffer = Symbol('kMessageBuffer');
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const kMessageBufferSize = Symbol('kMessageBufferSize');
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const kJSONBuffer = Symbol('kJSONBuffer');
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const kStringDecoder = Symbol('kStringDecoder');
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// Extend V8's serializer APIs to give more JSON-like behaviour in
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// some cases; in particular, for native objects this serializes them the same
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// way that JSON does rather than throwing an exception.
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const kArrayBufferViewTag = 0;
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const kNotArrayBufferViewTag = 1;
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class ChildProcessSerializer extends v8.DefaultSerializer {
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_writeHostObject(object) {
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if (isArrayBufferView(object)) {
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this.writeUint32(kArrayBufferViewTag);
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return super._writeHostObject(object);
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}
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this.writeUint32(kNotArrayBufferViewTag);
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this.writeValue({ ...object });
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}
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}
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class ChildProcessDeserializer extends v8.DefaultDeserializer {
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_readHostObject() {
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const tag = this.readUint32();
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if (tag === kArrayBufferViewTag)
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return super._readHostObject();
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assert(tag === kNotArrayBufferViewTag);
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return this.readValue();
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}
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}
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// Messages are parsed in either of the following formats:
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// - Newline-delimited JSON, or
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// - V8-serialized buffers, prefixed with their length as a big endian uint32
@@ -90,38 +61,22 @@ const advanced = {
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channel[kMessageBufferSize],
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);
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const deserializer = new ChildProcessDeserializer(
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TypedArrayPrototypeSubarray(concatenatedBuffer, 4, fullMessageSize),
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);
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const serializedMessage =
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TypedArrayPrototypeSubarray(concatenatedBuffer, 4, fullMessageSize);
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messageBufferHead = TypedArrayPrototypeSubarray(concatenatedBuffer, fullMessageSize);
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channel[kMessageBufferSize] = messageBufferHead.length;
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channel[kMessageBuffer] =
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channel[kMessageBufferSize] !== 0 ? [messageBufferHead] : [];
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deserializer.readHeader();
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yield deserializer.readValue();
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yield deserialize(serializedMessage);
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}
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channel.buffering = channel[kMessageBufferSize] > 0;
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},
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writeChannelMessage(channel, req, message, handle) {
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const ser = new ChildProcessSerializer();
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// Add 4 bytes, to later populate with message length
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ser.writeRawBytes(Buffer.allocUnsafe(4));
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ser.writeHeader();
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ser.writeValue(message);
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const serializedMessage = ser.releaseBuffer();
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const serializedMessageLength = serializedMessage.length - 4;
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serializedMessage.set([
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serializedMessageLength >> 24 & 0xFF,
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serializedMessageLength >> 16 & 0xFF,
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serializedMessageLength >> 8 & 0xFF,
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serializedMessageLength & 0xFF,
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], 0);
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const serializedMessage = serialize(message);
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const result = channel.writeBuffer(req, serializedMessage, handle);
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‎node.gyp‎

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@@ -136,6 +136,7 @@
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'src/node_http_parser.cc',
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'src/node_http2.cc',
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'src/node_i18n.cc',
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'src/node_ipc_serdes.cc',
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'src/node_locks.cc',
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'src/node_main_instance.cc',
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'src/node_messaging.cc',

‎src/node_binding.cc‎

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@@ -59,6 +59,7 @@
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V(http_parser) \
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V(inspector) \
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V(internal_only_v8) \
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V(ipc_serdes) \
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V(js_stream) \
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V(js_udp_wrap) \
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V(locks) \

‎src/node_external_reference.h‎

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@@ -84,6 +84,7 @@ class ExternalReferenceRegistry {
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V(heap_utils) \
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V(http_parser) \
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V(internal_only_v8) \
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V(ipc_serdes) \
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V(locks) \
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V(messaging) \
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V(mksnapshot) \

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