perf(preloader): tweak probabilities

Author: wmertens

packages/qwik/src/core/preloader/preloader.unit.ts

@@ -21,6 +21,6 @@ test('preloader script', () => {
    * dereference objects etc, but that actually results in worse compression
    */
   const compressed = compress(Buffer.from(preLoader), { mode: 1, quality: 11 });
-  expect(compressed.length).toBe(1716);
-  expect(preLoader.length).toBe(5114);
+  expect(compressed.length).toBe(1706);
+  expect(preLoader.length).toBe(5082);
 });

packages/qwik/src/core/preloader/queue.ts

@@ -216,7 +216,6 @@ export const preload = (name: string | (number | string)[], probability?: number
         inverseProbability = 1 - item / 10;
       } else {
         handleBundle(item, inverseProbability);
-        inverseProbability *= 1.005;
       }
     }
   } else {

packages/qwik/src/server/preload-impl.ts

@@ -1,6 +1,6 @@
 import { Fragment, jsx, type JSXNode } from '@builder.io/qwik';
 import type { ResolvedManifest } from '../optimizer/src/types';
-import { expandBundles } from './prefetch-strategy';
+import { expandBundles } from './preload-strategy';
 import type { PreloaderOptions } from './types';
 
 export function includePreloader(
@@ -126,8 +126,8 @@ function normalizePreLoaderOptions(
 }
 
 const PreLoaderOptionsDefault: Required<PreloaderOptions> = {
-  ssrPreloads: 5,
-  ssrPreloadProbability: 0.7,
+  ssrPreloads: 7,
+  ssrPreloadProbability: 0.5,
   debug: false,
   maxIdlePreloads: 25,
   preloadProbability: 0.35,

packages/qwik/src/server/prefetch-strategy.ts renamed to packages/qwik/src/server/preload-strategy.ts

@@ -1,7 +1,7 @@
 import type { ResolvedManifest } from '@builder.io/qwik/optimizer';
 import { getQueue, preload, resetQueue } from '../core/preloader/queue';
 import type { QRLInternal } from '../core/qrl/qrl-class';
-import { flattenPrefetchResources } from './prefetch-utils';
+import { flattenPrefetchResources } from './preload-utils';
 import type { RenderToStringOptions, SnapshotResult } from './types';
 import { getPlatform } from '@builder.io/qwik';
 import { getSymbolHash } from './platform';
@@ -66,10 +66,12 @@ export const expandBundles = (names: string[], resolvedManifest?: ResolvedManife
   resetQueue();
 
   let probability = 0.99;
-  for (const name of names) {
+  // we assume that after 15 symbols, we're beyond the first screenful of content
+  // the preloader will load the rest
+  for (const name of names.slice(0, 15)) {
     preload(name, probability);
     // later symbols have less probability
-    probability *= 0.95;
+    probability *= 0.85;
   }
 
   return getQueue().filter(

packages/qwik/src/server/prefetch-utils.ts renamed to packages/qwik/src/server/preload-utils.ts

@@ -1,5 +1,5 @@
 import { assert, test } from 'vitest';
-import { flattenPrefetchResources } from './prefetch-utils';
+import { flattenPrefetchResources } from './preload-utils';
 
 test('flattenPrefetchResources, no imports', () => {
   const p = [

packages/qwik/src/server/prefetch-utils.unit.ts renamed to packages/qwik/src/server/preload-utils.unit.ts

@@ -6,7 +6,7 @@ import { QInstance } from '../core/util/markers';
 import type { ResolvedManifest, SymbolMapper } from '../optimizer/src/types';
 import { getSymbolHash, setServerPlatform } from './platform';
 import { includePreloader } from './preload-impl';
-import { getPreloadPaths } from './prefetch-strategy';
+import { getPreloadPaths } from './preload-strategy';
 import { getQwikLoaderScript } from './scripts';
 import type {
   QwikManifest,