Bug 1801076 - Increase small heap incremental limit r=sfink

This change to delay reaching the GC urgent threshold while the heap is small
improved our Jetstream2 score by 2% on MacOS in testing.

Differential Revision: https://phabricator.services.mozilla.com/D162282

js/src/gc/Scheduling.h

@@ -360,7 +360,7 @@ static const size_t GCMinNurseryBytes = 256 * 1024;
  *
  * This must be greater than 1.3 to maintain performance on splay-latency.
  */
-static const double SmallHeapIncrementalLimit = 1.40;
+static const double SmallHeapIncrementalLimit = 1.50;
 
 /* JSGC_LARGE_HEAP_INCREMENTAL_LIMIT */
 static const double LargeHeapIncrementalLimit = 1.10;

js/src/jsapi.cpp

@@ -1430,7 +1430,7 @@ JS_PUBLIC_API void JS_SetGCParametersBasedOnAvailableMemory(
       {JSGC_LOW_FREQUENCY_HEAP_GROWTH, 150},
       {JSGC_ALLOCATION_THRESHOLD, 27},
       {JSGC_MALLOC_THRESHOLD_BASE, 38},
-      {JSGC_SMALL_HEAP_INCREMENTAL_LIMIT, 140},
+      {JSGC_SMALL_HEAP_INCREMENTAL_LIMIT, 150},
       {JSGC_LARGE_HEAP_INCREMENTAL_LIMIT, 110},
       {JSGC_URGENT_THRESHOLD_MB, 16}};
 

modules/libpref/init/all.js

@@ -1058,7 +1058,7 @@ pref("javascript.options.mem.gc_allocation_threshold_mb", 27);
 pref("javascript.options.mem.gc_malloc_threshold_base_mb", 38);
 
 // JSGC_SMALL_HEAP_INCREMENTAL_LIMIT
-pref("javascript.options.mem.gc_small_heap_incremental_limit", 140);
+pref("javascript.options.mem.gc_small_heap_incremental_limit", 150);
 
 // JSGC_LARGE_HEAP_INCREMENTAL_LIMIT
 pref("javascript.options.mem.gc_large_heap_incremental_limit", 110);