Chore: better download stat report

This commit is contained in:
SukkaW
2026-07-19 04:10:41 +08:00
parent 9d5d05e17c
commit 8a8b7c4f3d
4 changed files with 180 additions and 50 deletions

View File

@@ -120,11 +120,11 @@ const buildFinishedLock = path.join(ROOT_DIR, '.BUILD_FINISHED');
// write a file to demonstrate that the build is finished
fs.writeFileSync(buildFinishedLock, 'BUILD_FINISHED\n');
printExternalDownloadStats();
traces.forEach((t) => {
printTraceResult(t);
});
printStats(traces);
printExternalDownloadStats();
await Promise.all([
microsoftCdnWorker.end(),

View File

@@ -1,5 +1,6 @@
import picocolors from 'picocolors';
import { createPrettyBits, prettyBandwidth, prettyTraffic } from 'xbits';
import { appendArrayInPlace } from 'foxts/append-array-in-place';
export type ExternalDownloadOutcome = 'winner' | 'aborted' | 'failed';
@@ -9,17 +10,25 @@ export interface ExternalDownloadAttempt {
outcome: ExternalDownloadOutcome,
startedAt: number,
headersAt: number | null,
bodyStartedAt: number | null,
decodedBodyStartedAt: number | null,
encodedBodyStartedAt: number | null,
encodedBodyEndedAt: number | null,
endedAt: number,
bytes: number
decodedBytes: number,
encodedBytes: number,
contentEncoding: string | null
}
export interface ExternalDownloadStatsSnapshot {
attempts: ExternalDownloadAttempt[],
startedAt: number | null,
endedAt: number | null,
totalBytes: number,
usefulBytes: number,
wastedBytes: number,
totalDecodedBytes: number,
usefulDecodedBytes: number,
wastedDecodedBytes: number,
totalEncodedBytes: number,
usefulEncodedBytes: number,
wastedEncodedBytes: number,
winners: number,
aborted: number,
failed: number
@@ -27,11 +36,15 @@ export interface ExternalDownloadStatsSnapshot {
function createEmptySnapshot(): ExternalDownloadStatsSnapshot {
return {
attempts: [],
startedAt: null,
endedAt: null,
totalBytes: 0,
usefulBytes: 0,
wastedBytes: 0,
totalDecodedBytes: 0,
usefulDecodedBytes: 0,
wastedDecodedBytes: 0,
totalEncodedBytes: 0,
usefulEncodedBytes: 0,
wastedEncodedBytes: 0,
winners: 0,
aborted: 0,
failed: 0
@@ -62,36 +75,60 @@ function formatDuration(duration: number | null) {
return duration == null ? 'n/a' : `${duration.toFixed(1)}ms`;
}
function formatCompressionRatio(decodedBytes: number, encodedBytes: number) {
return encodedBytes <= 0 ? 'n/a' : `${(decodedBytes / encodedBytes).toFixed(2)}x`;
}
export function recordExternalDownloadAttempt(attempt: ExternalDownloadAttempt) {
stats.attempts.push(attempt);
stats.startedAt = stats.startedAt == null ? attempt.startedAt : Math.min(stats.startedAt, attempt.startedAt);
stats.endedAt = stats.endedAt == null ? attempt.endedAt : Math.max(stats.endedAt, attempt.endedAt);
stats.totalBytes += attempt.bytes;
stats.totalDecodedBytes += attempt.decodedBytes;
stats.totalEncodedBytes += attempt.encodedBytes;
if (attempt.outcome === 'winner') {
stats.winners++;
stats.usefulBytes += attempt.bytes;
stats.usefulDecodedBytes += attempt.decodedBytes;
stats.usefulEncodedBytes += attempt.encodedBytes;
} else {
stats.wastedBytes += attempt.bytes;
stats.wastedDecodedBytes += attempt.decodedBytes;
stats.wastedEncodedBytes += attempt.encodedBytes;
if (attempt.outcome === 'aborted') {
stats.aborted++;
} else {
stats.failed++;
}
}
}
function printExternalDownloadAttempt(attempt: ExternalDownloadAttempt) {
const ttfb = attempt.headersAt == null ? null : attempt.headersAt - attempt.startedAt;
const queueWait = attempt.headersAt == null || attempt.bodyStartedAt == null
const queueWait = attempt.headersAt == null || attempt.decodedBodyStartedAt == null
? null
: attempt.bodyStartedAt - attempt.headersAt;
const bodyDuration = attempt.bodyStartedAt == null ? null : attempt.endedAt - attempt.bodyStartedAt;
const speed = bodyDuration == null ? 'n/a' : formatDownloadSpeed(attempt.bytes, bodyDuration);
: attempt.decodedBodyStartedAt - attempt.headersAt;
const encodedBodyDuration = attempt.encodedBodyStartedAt == null || attempt.encodedBodyEndedAt == null
? null
: attempt.encodedBodyEndedAt - attempt.encodedBodyStartedAt;
const decodedBodyDuration = attempt.decodedBodyStartedAt == null
? null
: attempt.endedAt - attempt.decodedBodyStartedAt;
const encodedSpeed = encodedBodyDuration == null
? 'n/a'
: formatDownloadSpeed(attempt.encodedBytes, encodedBodyDuration);
const decodedSpeed = decodedBodyDuration == null
? 'n/a'
: formatDownloadSpeed(attempt.decodedBytes, decodedBodyDuration);
console.log(
picocolors.gray('[external download]'),
attempt.kind,
attempt.outcome,
prettyTraffic(attempt.bytes),
speed,
`encoded=${prettyTraffic(attempt.encodedBytes)}`,
encodedSpeed,
`decoded=${prettyTraffic(attempt.decodedBytes)}`,
decodedSpeed,
`ratio=${formatCompressionRatio(attempt.decodedBytes, attempt.encodedBytes)}`,
`encoding=${attempt.contentEncoding ?? 'identity'}`,
`ttfb=${formatDuration(ttfb)}`,
`queue=${formatDuration(queueWait)}`,
attempt.url
@@ -103,15 +140,19 @@ export function mergeExternalDownloadStats(snapshot: ExternalDownloadStatsSnapsh
return;
}
appendArrayInPlace(stats.attempts, snapshot.attempts);
if (snapshot.startedAt != null) {
stats.startedAt = stats.startedAt == null ? snapshot.startedAt : Math.min(stats.startedAt, snapshot.startedAt);
}
if (snapshot.endedAt != null) {
stats.endedAt = stats.endedAt == null ? snapshot.endedAt : Math.max(stats.endedAt, snapshot.endedAt);
}
stats.totalBytes += snapshot.totalBytes;
stats.usefulBytes += snapshot.usefulBytes;
stats.wastedBytes += snapshot.wastedBytes;
stats.totalDecodedBytes += snapshot.totalDecodedBytes;
stats.usefulDecodedBytes += snapshot.usefulDecodedBytes;
stats.wastedDecodedBytes += snapshot.wastedDecodedBytes;
stats.totalEncodedBytes += snapshot.totalEncodedBytes;
stats.usefulEncodedBytes += snapshot.usefulEncodedBytes;
stats.wastedEncodedBytes += snapshot.wastedEncodedBytes;
stats.winners += snapshot.winners;
stats.aborted += snapshot.aborted;
stats.failed += snapshot.failed;
@@ -128,13 +169,21 @@ export function printExternalDownloadStats() {
return;
}
console.log(picocolors.bold('[external downloads]'), `attempts=${stats.attempts.length}`);
stats.attempts
.toSorted((a, b) => a.startedAt - b.startedAt)
.forEach(printExternalDownloadAttempt);
const duration = stats.endedAt - stats.startedAt;
console.log(
picocolors.bold('[external downloads total]'),
`useful=${prettyTraffic(stats.usefulBytes)}`,
`transferred=${prettyTraffic(stats.totalBytes)}`,
`hedge-waste=${prettyTraffic(stats.wastedBytes)}`,
`avg=${formatDownloadSpeed(stats.totalBytes, duration)}`,
`encoded-useful=${prettyTraffic(stats.usefulEncodedBytes)}`,
`encoded-transferred=${prettyTraffic(stats.totalEncodedBytes)}`,
`encoded-hedge-waste=${prettyTraffic(stats.wastedEncodedBytes)}`,
`encoded-avg=${formatDownloadSpeed(stats.totalEncodedBytes, duration)}`,
`decoded-useful=${prettyTraffic(stats.usefulDecodedBytes)}`,
`decoded-avg=${formatDownloadSpeed(stats.totalDecodedBytes, duration)}`,
`ratio=${formatCompressionRatio(stats.totalDecodedBytes, stats.totalEncodedBytes)}`,
`wall=${formatDuration(duration)}`,
`winner=${stats.winners}`,
`aborted=${stats.aborted}`,

View File

@@ -20,9 +20,10 @@ const MIN_HEDGE_DELAY = 3000;
const HEDGE_DELAY_STEP = 1200;
const HEDGE_SPEED_SAMPLE_INTERVAL = 1000;
const HEDGE_QUEUE_POLL_INTERVAL = 250;
// 1 MiB/s is about 8.4 Mbps. A source throttled to 5 Mbps will be hedged,
// while larger responses making healthy progress will not be raced merely
// because their total download time exceeds three seconds.
// This threshold is evaluated against encoded response bytes, before fetch()
// decompresses them. 1 MiB/s is about 8.4 Mbps on the network, so a source
// throttled to 5 Mbps will be hedged, while a larger compressed response making
// healthy progress will not be raced merely because decoding expands its body.
const MIN_ACCEPTABLE_DOWNLOAD_BYTES_PER_SECOND = 1024 * 1024;
export function isDownloadThroughputSlow(bytesReceived: number, elapsed: number) {
@@ -31,8 +32,10 @@ export function isDownloadThroughputSlow(bytesReceived: number, elapsed: number)
interface PrimaryDownloadProgress {
headersReceived: boolean,
bodyStartedAt: number | null,
bytesReceived: number,
bodyConsumptionStartedAt: number | null,
encodedBytesAtConsumptionStart: number,
encodedBytesReceived: number,
encodedBodyComplete: boolean,
failed: boolean
}
@@ -43,8 +46,10 @@ export async function fetchAssets(
const controller = new AbortController();
const primaryProgress: PrimaryDownloadProgress = {
headersReceived: false,
bodyStartedAt: null,
bytesReceived: 0,
bodyConsumptionStartedAt: null,
encodedBytesAtConsumptionStart: 0,
encodedBytesReceived: 0,
encodedBodyComplete: false,
failed: false
};
@@ -61,7 +66,7 @@ export async function fetchAssets(
return;
}
if (primaryProgress.bodyStartedAt == null) {
if (primaryProgress.bodyConsumptionStartedAt == null) {
// The response is waiting for our local body-consumption queue. This is
// not an upstream slowdown and should not trigger a duplicate request.
// eslint-disable-next-line no-await-in-loop -- poll until local consumption starts
@@ -69,7 +74,18 @@ export async function fetchAssets(
continue;
}
sampledAt ??= primaryProgress.bodyStartedAt;
if (primaryProgress.encodedBodyComplete) {
// The full encoded body is already local. Any remaining time belongs
// to decompression or parsing, which a fallback can not improve.
// eslint-disable-next-line no-await-in-loop -- wait for local processing to finish
await waitWithAbort(HEDGE_QUEUE_POLL_INTERVAL, controller.signal);
continue;
}
if (sampledAt == null) {
sampledAt = primaryProgress.bodyConsumptionStartedAt;
sampledBytes = primaryProgress.encodedBytesAtConsumptionStart;
}
const now = performance.now();
const sampleDuration = now - sampledAt;
@@ -79,12 +95,12 @@ export async function fetchAssets(
continue;
}
if (isDownloadThroughputSlow(primaryProgress.bytesReceived - sampledBytes, sampleDuration)) {
if (isDownloadThroughputSlow(primaryProgress.encodedBytesReceived - sampledBytes, sampleDuration)) {
return;
}
sampledAt = now;
sampledBytes = primaryProgress.bytesReceived;
sampledBytes = primaryProgress.encodedBytesReceived;
// eslint-disable-next-line no-await-in-loop -- periodically re-sample a healthy transfer
await waitWithAbort(HEDGE_SPEED_SAMPLE_INTERVAL, controller.signal);
}
@@ -111,8 +127,12 @@ export async function fetchAssets(
const isPrimary = index < 0;
const attemptStartedAt = downloadTimestamp();
let headersAt: number | null = null;
let bodyStartedAt: number | null = null;
let attemptBytes = 0;
let decodedBodyStartedAt: number | null = null;
let encodedBodyStartedAt: number | null = null;
let encodedBodyEndedAt: number | null = null;
let decodedBytes = 0;
let encodedBytes = 0;
let contentEncoding: string | null = null;
let finalized = false;
const finalizeAttempt = (outcome: ExternalDownloadOutcome) => {
@@ -126,17 +146,42 @@ export async function fetchAssets(
outcome,
startedAt: attemptStartedAt,
headersAt,
bodyStartedAt,
decodedBodyStartedAt,
encodedBodyStartedAt,
encodedBodyEndedAt,
endedAt: downloadTimestamp(),
bytes: attemptBytes
decodedBytes,
encodedBytes,
contentEncoding
});
};
try {
// We intentionally acquire the body-consumption queue after receiving
// headers. Request scheduling will be handled separately.
const res = await $$fetch(url, { signal: controller.signal, ...defaultRequestInit });
headersAt = downloadTimestamp();
const res = await $$fetch(url, { signal: controller.signal, ...defaultRequestInit }, {
onResponseStart(encoding) {
headersAt = downloadTimestamp();
contentEncoding = encoding;
if (isPrimary) {
primaryProgress.headersReceived = true;
}
},
onEncodedBodyChunk(bytes) {
encodedBodyStartedAt ??= downloadTimestamp();
encodedBytes += bytes;
if (isPrimary) {
primaryProgress.encodedBytesReceived += bytes;
}
},
onEncodedBodyEnd(completed) {
encodedBodyEndedAt = downloadTimestamp();
if (isPrimary) {
primaryProgress.encodedBodyComplete = completed;
}
}
});
headersAt ??= downloadTimestamp();
let body = nullthrow(res.body, url + ' has an empty body');
if (isPrimary) {
@@ -144,10 +189,7 @@ export async function fetchAssets(
}
body = body.pipeThrough(new TransformStream<Uint8Array, Uint8Array>({
transform(chunk, streamController) {
attemptBytes += chunk.byteLength;
if (isPrimary) {
primaryProgress.bytesReceived += chunk.byteLength;
}
decodedBytes += chunk.byteLength;
streamController.enqueue(chunk);
}
}));
@@ -163,9 +205,10 @@ export async function fetchAssets(
}
const arr = await queue.add(() => {
bodyStartedAt = downloadTimestamp();
decodedBodyStartedAt = downloadTimestamp();
if (isPrimary) {
primaryProgress.bodyStartedAt = performance.now();
primaryProgress.bodyConsumptionStartedAt = performance.now();
primaryProgress.encodedBytesAtConsumptionStart = primaryProgress.encodedBytesReceived;
}
return Array.fromAsync(stream);
});

View File

@@ -174,6 +174,40 @@ const agent = new Agent({
})
);
export interface FetchResponseProgress {
onResponseStart?: (contentEncoding: string | null) => void,
onEncodedBodyChunk?: (bytes: number) => void,
onEncodedBodyEnd?: (completed: boolean) => void
}
function createResponseProgressDispatcher(progress: FetchResponseProgress): Dispatcher {
return agent.compose(dispatch => (opts, handler) => dispatch(opts, {
onRequestStart: (...args) => handler.onRequestStart?.(...args),
onRequestUpgrade: (...args) => handler.onRequestUpgrade?.(...args),
onResponseStart(controller, statusCode, headers, statusMessage) {
const contentEncoding = headers['content-encoding'];
progress.onResponseStart?.(
contentEncoding == null
? null
: (Array.isArray(contentEncoding) ? contentEncoding.join(', ') : contentEncoding)
);
return handler.onResponseStart?.(controller, statusCode, headers, statusMessage);
},
onResponseData(controller, chunk) {
progress.onEncodedBodyChunk?.(chunk.byteLength);
return handler.onResponseData?.(controller, chunk);
},
onResponseEnd(...args) {
progress.onEncodedBodyEnd?.(true);
return handler.onResponseEnd?.(...args);
},
onResponseError(...args) {
progress.onEncodedBodyEnd?.(false);
return handler.onResponseError?.(...args);
}
}));
}
function calculateRetryAfterHeader(retryAfter: string) {
const current = Date.now();
return new Date(retryAfter).getTime() - current;
@@ -209,8 +243,12 @@ export const defaultRequestInit = {
}
};
export async function $$fetch(url: RequestInfo, init: RequestInit = defaultRequestInit) {
init.dispatcher = agent;
export async function $$fetch(
url: RequestInfo,
init: RequestInit = defaultRequestInit,
progress?: FetchResponseProgress
) {
init.dispatcher = progress == null ? agent : createResponseProgressDispatcher(progress);
try {
const res = await undici.fetch(url, init);