nodejs
/
node
mirror of https://github.com/nodejs/node.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

lib: performance improvement on readline async iterator 

Using a direct approach to create the readline async iterator
allowed an iteration over 20 to 58% faster.

**BREAKING CHANGE**: With that change, the async iteterator
obtained from the readline interface doesn't have the
property "stream" any longer. This happened because it's no
longer created through a Readable, instead, the async
iterator is created directly from the events of the readline
interface instance, so, if anyone is using that property,
this change will break their code.
Also, the Readable added a backpressure control that is
fairly compensated by the use of FixedQueue + monitoring
its size. This control wasn't really precise with readline
before, though, because it only pauses the reading of the
original stream, but the lines generated from the last
message received from it was still emitted. For example:
if the readable was paused at 1000 messages but the last one
received generated 10k lines, but no further messages were
emitted again until the queue was lower than the readable
highWaterMark. A similar  behavior still happens with the
new implementation, but the highWaterMark used is fixed: 1024,
and the original stream is resumed again only after the queue
is cleared.

Before making that change, I created a package implementing
the same concept used here to validate it. You can find it
[here](https://github.com/Farenheith/faster-readline-iterator)
if this helps anyhow.

PR-URL: https://github.com/nodejs/node/pull/41276
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
This commit is contained in:
Thiago Oliveira Santos 2022-10-24 09:49:16 -03:00 committed by GitHub
parent aab9f3246e
commit 0f3e531096
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
7 changed files with 362 additions and 99 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

48
benchmark/readline/readline-iterable.js Normal file
View File

@ -0,0 +1,48 @@
'use strict';
const common = require('../common.js');
const readline = require('readline');
const { Readable } = require('stream');
const bench = common.createBenchmark(main, {
n: [1e1, 1e2, 1e3, 1e4, 1e5, 1e6],
});
const loremIpsum = `Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed
do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Dui accumsan sit amet nulla facilisi morbi tempus iaculis urna.
Eget dolor morbi non arcu risus quis varius quam quisque.
Lacus viverra vitae congue eu consequat ac felis donec.
Amet porttitor eget dolor morbi non arcu.
Velit ut tortor pretium viverra suspendisse.
Mauris nunc congue nisi vitae suscipit tellus.
Amet nisl suscipit adipiscing bibendum est ultricies integer.
Sit amet dictum sit amet justo donec enim diam.
Condimentum mattis pellentesque id nibh tortor id aliquet lectus proin.
Diam in arcu cursus euismod quis viverra nibh.
Rest of line`;
function getLoremIpsumStream(repetitions) {
const readable = Readable({
objectMode: true,
});
let i = 0;
readable._read = () => readable.push(
i++ >= repetitions ? null : loremIpsum
);
return readable;
}
async function main({ n }) {
bench.start();
let lineCount = 0;
const iterable = readline.createInterface({
input: getLoremIpsumStream(n),
});
// eslint-disable-next-line no-unused-vars
for await (const _ of iterable) {
lineCount++;
}
bench.end(lineCount);
}

166
lib/events.js
View File

@ -23,7 +23,8 @@
const {
ArrayPrototypeJoin,
ArrayPrototypeShift,
ArrayPrototypePop,
ArrayPrototypePush,
ArrayPrototypeSlice,
ArrayPrototypeSplice,
ArrayPrototypeUnshift,
@ -33,6 +34,7 @@ const {
FunctionPrototypeBind,
FunctionPrototypeCall,
NumberIsNaN,
NumberMAX_SAFE_INTEGER,
ObjectCreate,
ObjectDefineProperty,
ObjectDefineProperties,
@ -59,6 +61,8 @@ const {
} = require('internal/util/inspect');
let spliceOne;
let FixedQueue;
let kFirstEventParam;
const {
AbortError,
@ -73,6 +77,7 @@ const {
} = require('internal/errors');
const {
validateInteger,
validateAbortSignal,
validateBoolean,
validateFunction,
@ -84,6 +89,7 @@ const kErrorMonitor = Symbol('events.errorMonitor');
const kMaxEventTargetListeners = Symbol('events.maxEventTargetListeners');
const kMaxEventTargetListenersWarned =
Symbol('events.maxEventTargetListenersWarned');
const kWatermarkData = SymbolFor('nodejs.watermarkData');
let EventEmitterAsyncResource;
// The EventEmitterAsyncResource has to be initialized lazily because event.js
@ -999,25 +1005,44 @@ function eventTargetAgnosticAddListener(emitter, name, listener, flags) {
* Returns an `AsyncIterator` that iterates `event` events.
* @param {EventEmitter} emitter
* @param {string | symbol} event
* @param {{ signal: AbortSignal; }} [options]
* @param {{
* signal: AbortSignal;
* close?: string[];
* highWatermark?: number,
* lowWatermark?: number
* }} [options]
* @returns {AsyncIterator}
*/
function on(emitter, event, options) {
const signal = options?.signal;
function on(emitter, event, options = {}) {
// Parameters validation
const signal = options.signal;
validateAbortSignal(signal, 'options.signal');
if (signal?.aborted)
throw new AbortError(undefined, { cause: signal?.reason });
const highWatermark = options.highWatermark ?? NumberMAX_SAFE_INTEGER;
validateInteger(highWatermark, 'options.highWatermark', 1);
const lowWatermark = options.lowWatermark ?? 1;
validateInteger(lowWatermark, 'options.lowWatermark', 1);
const unconsumedEvents = [];
const unconsumedPromises = [];
// Preparing controlling queues and variables
FixedQueue ??= require('internal/fixed_queue');
const unconsumedEvents = new FixedQueue();
const unconsumedPromises = new FixedQueue();
let paused = false;
let error = null;
let finished = false;
let size = 0;
const iterator = ObjectSetPrototypeOf({
next() {
// First, we consume all unread events
const value = unconsumedEvents.shift();
if (value) {
if (size) {
const value = unconsumedEvents.shift();
size--;
if (paused && size < lowWatermark) {
emitter.resume();
paused = false;
}
return PromiseResolve(createIterResult(value, false));
}
@ -1032,9 +1057,7 @@ function on(emitter, event, options) {
}
// If the iterator is finished, resolve to done
if (finished) {
return PromiseResolve(createIterResult(undefined, true));
}
if (finished) return closeHandler();
// Wait until an event happens
return new Promise(function(resolve, reject) {
@ -1043,24 +1066,7 @@ function on(emitter, event, options) {
},
return() {
eventTargetAgnosticRemoveListener(emitter, event, eventHandler);
eventTargetAgnosticRemoveListener(emitter, 'error', errorHandler);
if (signal) {
eventTargetAgnosticRemoveListener(
signal,
'abort',
abortListener,
{ once: true });
}
finished = true;
for (const promise of unconsumedPromises) {
promise.resolve(createIterResult(undefined, true));
}
return PromiseResolve(createIterResult(undefined, true));
return closeHandler();
},
throw(err) {
@ -1068,21 +1074,54 @@ function on(emitter, event, options) {
throw new ERR_INVALID_ARG_TYPE('EventEmitter.AsyncIterator',
'Error', err);
}
error = err;
eventTargetAgnosticRemoveListener(emitter, event, eventHandler);
eventTargetAgnosticRemoveListener(emitter, 'error', errorHandler);
errorHandler(err);
},
[SymbolAsyncIterator]() {
return this;
}
},
[kWatermarkData]: {
/**
* The current queue size
*/
get size() {
return size;
},
/**
* The low watermark. The emitter is resumed every time size is lower than it
*/
get low() {
return lowWatermark;
},
/**
* The high watermark. The emitter is paused every time size is higher than it
*/
get high() {
return highWatermark;
},
/**
* It checks wether the emitter is paused by the watermark controller or not
*/
get isPaused() {
return paused;
}
},
}, AsyncIteratorPrototype);
eventTargetAgnosticAddListener(emitter, event, eventHandler);
// Adding event handlers
const { addEventListener, removeAll } = listenersController();
kFirstEventParam ??= require('internal/events/symbols').kFirstEventParam;
addEventListener(emitter, event, options[kFirstEventParam] ? eventHandler : function(...args) {
return eventHandler(args);
});
if (event !== 'error' && typeof emitter.on === 'function') {
emitter.on('error', errorHandler);
addEventListener(emitter, 'error', errorHandler);
}
const closeEvents = options?.close;
if (closeEvents?.length) {
for (let i = 0; i < closeEvents.length; i++) {
addEventListener(emitter, closeEvents[i], closeHandler);
}
}
if (signal) {
eventTargetAgnosticAddListener(
signal,
@ -1097,27 +1136,48 @@ function on(emitter, event, options) {
errorHandler(new AbortError(undefined, { cause: signal?.reason }));
}
function eventHandler(...args) {
const promise = ArrayPrototypeShift(unconsumedPromises);
if (promise) {
promise.resolve(createIterResult(args, false));
} else {
unconsumedEvents.push(args);
}
function eventHandler(value) {
if (unconsumedPromises.isEmpty()) {
size++;
if (!paused && size > highWatermark) {
paused = true;
emitter.pause();
}
unconsumedEvents.push(value);
} else unconsumedPromises.shift().resolve(createIterResult(value, false));
}
function errorHandler(err) {
if (unconsumedPromises.isEmpty()) error = err;
else unconsumedPromises.shift().reject(err);
closeHandler();
}
function closeHandler() {
removeAll();
finished = true;
const toError = ArrayPrototypeShift(unconsumedPromises);
if (toError) {
toError.reject(err);
} else {
// The next time we call next()
error = err;
const doneResult = createIterResult(undefined, true);
while (!unconsumedPromises.isEmpty()) {
unconsumedPromises.shift().resolve(doneResult);
}
iterator.return();
return PromiseResolve(doneResult);
}
}
function listenersController() {
const listeners = [];
return {
addEventListener(emitter, event, handler, flags) {
eventTargetAgnosticAddListener(emitter, event, handler, flags);
ArrayPrototypePush(listeners, [emitter, event, handler, flags]);
},
removeAll() {
while (listeners.length > 0) {
ReflectApply(eventTargetAgnosticRemoveListener, undefined, ArrayPrototypePop(listeners));
}
}
};
}

11
lib/internal/events/symbols.js Normal file
View File

@ -0,0 +1,11 @@
'use strict';
const {
Symbol,
} = primordials;
const kFirstEventParam = Symbol('nodejs.kFirstEventParam');
module.exports = {
kFirstEventParam,
};

45
lib/internal/readline/interface.js
View File

@ -62,6 +62,7 @@ const {
kSubstringSearch,
} = require('internal/readline/utils');
let emitKeypressEvents;
let kFirstEventParam;
const {
clearScreenDown,
cursorTo,
@ -70,9 +71,6 @@ const {
const { StringDecoder } = require('string_decoder');
// Lazy load Readable for startup performance.
let Readable;
const kHistorySize = 30;
const kMaxUndoRedoStackSize = 2048;
const kMincrlfDelay = 100;
@ -1346,40 +1344,15 @@ class Interface extends InterfaceConstructor {
*/
[SymbolAsyncIterator]() {
if (this[kLineObjectStream] === undefined) {
if (Readable === undefined) {
Readable = require('stream').Readable;
}
const readable = new Readable({
objectMode: true,
read: () => {
this.resume();
},
destroy: (err, cb) => {
this.off('line', lineListener);
this.off('close', closeListener);
this.close();
cb(err);
},
});
const lineListener = (input) => {
if (!readable.push(input)) {
// TODO(rexagod): drain to resume flow
this.pause();
}
};
const closeListener = () => {
readable.push(null);
};
const errorListener = (err) => {
readable.destroy(err);
};
this.on('error', errorListener);
this.on('line', lineListener);
this.on('close', closeListener);
this[kLineObjectStream] = readable;
kFirstEventParam ??= require('internal/events/symbols').kFirstEventParam;
this[kLineObjectStream] = EventEmitter.on(
this, 'line', {
close: ['close'],
highWatermark: 1024,
[kFirstEventParam]: true,
});
}
return this[kLineObjectStream][SymbolAsyncIterator]();
return this[kLineObjectStream];
}
}

7
test/benchmark/test-bechmark-readline.js Normal file
View File

@ -0,0 +1,7 @@
'use strict';
require('../common');
const runBenchmark = require('../common/benchmark');
runBenchmark('readline', { NODEJS_BENCHMARK_ZERO_ALLOWED: 1 });

26
test/parallel/test-readline-async-iterators-backpressure.js
View File

@ -6,11 +6,17 @@ const { Readable } = require('stream');
const readline = require('readline');
const CONTENT = 'content';
const TOTAL_LINES = 18;
const LINES_PER_PUSH = 2051;
const REPETITIONS = 3;
(async () => {
const readable = new Readable({ read() {} });
readable.push(`${CONTENT}\n`.repeat(TOTAL_LINES));
let salt = 0;
for (let i = 0; i < REPETITIONS; i++) {
readable.push(`${CONTENT}\n`.repeat(LINES_PER_PUSH + i));
salt += i;
}
const TOTAL_LINES = LINES_PER_PUSH * REPETITIONS + salt;
const rli = readline.createInterface({
input: readable,
@ -18,21 +24,24 @@ const TOTAL_LINES = 18;
});
const it = rli[Symbol.asyncIterator]();
const highWaterMark = it.stream.readableHighWaterMark;
const watermarkData = it[Symbol.for('nodejs.watermarkData')];
const highWaterMark = watermarkData.high;
// For this test to work, we have to queue up more than the number of
// highWaterMark items in rli. Make sure that is the case.
assert(TOTAL_LINES > highWaterMark);
assert(TOTAL_LINES > highWaterMark, `TOTAL_LINES (${TOTAL_LINES}) isn't greater than highWaterMark (${highWaterMark})`);
let iterations = 0;
let readableEnded = false;
let notPaused = 0;
for await (const line of it) {
assert.strictEqual(readableEnded, false);
assert.strictEqual(line, CONTENT);
const expectedPaused = TOTAL_LINES - iterations > highWaterMark;
assert.strictEqual(readable.isPaused(), expectedPaused);
assert.ok(watermarkData.size <= TOTAL_LINES);
assert.strictEqual(readable.isPaused(), watermarkData.size >= 1);
if (!readable.isPaused()) {
notPaused++;
}
iterations += 1;
@ -45,4 +54,5 @@ const TOTAL_LINES = 18;
}
assert.strictEqual(iterations, TOTAL_LINES);
assert.strictEqual(notPaused, REPETITIONS);
})().then(common.mustCall());

158
test/parallel/test-readline-async-iterators.js
View File

@ -4,6 +4,7 @@ const common = require('../common');
const fs = require('fs');
const { join } = require('path');
const readline = require('readline');
const { Readable } = require('stream');
const assert = require('assert');
const tmpdir = require('../common/tmpdir');
@ -63,7 +64,6 @@ async function testMutual() {
// This outer loop should only iterate once.
assert.strictEqual(iterated, false);
iterated = true;
iteratedLines.push(k);
for await (const l of rli) {
iteratedLines.push(l);
@ -74,4 +74,158 @@ async function testMutual() {
}
}
testSimple().then(testMutual).then(common.mustCall());
async function testPerformance() {
const loremIpsum = `Lorem ipsum dolor sit amet, consectetur adipiscing elit,
sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Dui accumsan sit amet nulla facilisi morbi tempus iaculis urna.
Eget dolor morbi non arcu risus quis varius quam quisque.
Lacus viverra vitae congue eu consequat ac felis donec.
Amet porttitor eget dolor morbi non arcu.
Velit ut tortor pretium viverra suspendisse.
Mauris nunc congue nisi vitae suscipit tellus.
Amet nisl suscipit adipiscing bibendum est ultricies integer.
Sit amet dictum sit amet justo donec enim diam.
Condimentum mattis pellentesque id nibh tortor id aliquet lectus proin.
Diam in arcu cursus euismod quis viverra nibh.
`;
const REPETITIONS = 10000;
const SAMPLE = 100;
const THRESHOLD = 81;
function getLoremIpsumStream() {
const readable = Readable({
objectMode: true,
});
let i = 0;
readable._read = () => readable.push(
i++ >= REPETITIONS ? null : loremIpsum
);
return readable;
}
function oldWay() {
const readable = new Readable({
objectMode: true,
read: () => {
this.resume();
},
destroy: (err, cb) => {
this.off('line', lineListener);
this.off('close', closeListener);
this.close();
cb(err);
},
});
const lineListener = (input) => {
if (!readable.push(input)) {
// TODO(rexagod): drain to resume flow
this.pause();
}
};
const closeListener = () => {
readable.push(null);
};
const errorListener = (err) => {
readable.destroy(err);
};
this.on('error', errorListener);
this.on('line', lineListener);
this.on('close', closeListener);
return readable[Symbol.asyncIterator]();
}
function getAvg(mean, x, n) {
return (mean * n + x) / (n + 1);
}
let totalTimeOldWay = 0;
let totalTimeNewWay = 0;
let totalCharsOldWay = 0;
let totalCharsNewWay = 0;
const linesOldWay = [];
const linesNewWay = [];
for (let time = 0; time < SAMPLE; time++) {
const rlOldWay = readline.createInterface({
input: getLoremIpsumStream(),
});
let currenttotalTimeOldWay = Date.now();
for await (const line of oldWay.call(rlOldWay)) {
totalCharsOldWay += line.length;
if (time === 0) {
linesOldWay.push(line);
}
}
currenttotalTimeOldWay = Date.now() - currenttotalTimeOldWay;
totalTimeOldWay = getAvg(totalTimeOldWay, currenttotalTimeOldWay, SAMPLE);
const rlNewWay = readline.createInterface({
input: getLoremIpsumStream(),
});
let currentTotalTimeNewWay = Date.now();
for await (const line of rlNewWay) {
totalCharsNewWay += line.length;
if (time === 0) {
linesNewWay.push(line);
}
}
currentTotalTimeNewWay = Date.now() - currentTotalTimeNewWay;
totalTimeNewWay = getAvg(totalTimeNewWay, currentTotalTimeNewWay, SAMPLE);
}
assert.strictEqual(totalCharsOldWay, totalCharsNewWay);
assert.strictEqual(linesOldWay.length, linesNewWay.length);
linesOldWay.forEach((line, index) =>
assert.strictEqual(line, linesNewWay[index])
);
const percentage = totalTimeNewWay * 100 / totalTimeOldWay;
assert.ok(percentage <= THRESHOLD, `Failed: ${totalTimeNewWay} isn't lesser than ${THRESHOLD}% of ${totalTimeOldWay}. Actual percentage: ${percentage.toFixed(2)}%`);
}
async function testSlowStreamForLeaks() {
const message = 'a\nb\nc\n';
const DELAY = 1;
const REPETITIONS = 100;
const warningCallback = common.mustNotCall();
process.on('warning', warningCallback);
function getStream() {
const readable = Readable({
objectMode: true,
});
readable._read = () => {};
let i = REPETITIONS;
function schedule() {
setTimeout(() => {
i--;
if (i < 0) {
readable.push(null);
} else {
readable.push(message);
schedule();
}
}, DELAY);
}
schedule();
return readable;
}
const iterable = readline.createInterface({
input: getStream(),
});
let lines = 0;
// eslint-disable-next-line no-unused-vars
for await (const _ of iterable) {
lines++;
}
assert.strictEqual(lines, 3 * REPETITIONS);
process.off('warning', warningCallback);
}
testSimple()
.then(testMutual)
.then(testPerformance)
.then(testSlowStreamForLeaks)
.then(common.mustCall());