dart-sdk/runtime/lib/integers.h
Alexander Aprelev 8c0df46887 [vm] Better implementation of hashCode function.
With this cl hashCode function for integers which used to be identity function becomes `uint128_t hash = value * constant; hash ^= hash >> 64; hash ^= hash >> 32; hash &= 0x3fffffff`. Note that the hashCode has to stay the same across platforms(64-bit/32-bit).

This dramatically improves performance of integer HashSet/HashMap lookups when integers differ in higher bits only(see the issue referenced below).

AOT ARM64 benchmarks:
===
WordSolverIdentity -3.630% (-0.9 noise)
BigInt.parse.0064.bits 15.43% (0.9 noise)
BigInt.parse.4096.bits 40.80% (1.6 noise)
BigInt.parse.0256.bits 42.01% (2.3 noise)
BigInt.parse.1024.bits 50.91% (2.6 noise)
IntegerSetLookup.DefaultHashSet 549916% (14727.6 noise)
IntegerSetLookup.DefaultHashSet 597150% (55520.2 noise)
IntegerSetLookup.HashSet 846924% (78126.7 noise)
IntegerSetLookup.HashSet 791864% (107221.1 noise)
===

AOT x64:
===
Havlak -14.25% (-1.7 noise)
DartMicroBench.Int64Div -7.091% (-1.2 noise)
ObjectHash.manual.5 -9.541% (-0.8 noise)
AsyncLiveVars.LiveInt1 4.726% (0.8 noise)
IsolateJson.SendAndExit_Decode1MBx1 9.067% (0.8 noise)
SplayHarderLatency 4.629% (0.9 noise)
TypedDataDuplicate.Float64List.32.loop 35.01% (1.8 noise)
IntegerSetLookup.DefaultHashSet 627996% (124823.6 noise)
IntegerSetLookup.HashSet 1245362% (244705.3 noise)
===

JIT ARM64:
===
IntegerSetLookup.DefaultHashSet_Random 73.80% (1.2 noise)
IntegerSetLookup.DefaultHashSet 344999% (6202.9 noise)
IntegerSetLookup.HashSet 483731% (7845.7 noise)
===

JIT x64:
===
CollectionSieves-Set-removeLoop -6.294% (-0.9 noise)
Utf8Encode.ru.10M 59.11% (0.8 noise)
Utf8Encode.ru.10k 71.62% (0.9 noise)
Utf8Encode.zh.10M 53.93% (0.9 noise)
Utf8Encode.ne.10k 71.34% (0.9 noise)
Utf8Encode.zh.10k 72.52% (0.9 noise)
Utf8Encode.ne.10M 53.17% (0.9 noise)
IntegerSetLookup.HashSet_Random 27.80% (1.1 noise)
String.replaceAll.String.Zero 8.659% (1.2 noise)
IntegerSetLookup.DefaultHashSet_Random 96.20% (1.3 noise)
IntegerSetLookup.HashSet 481037% (18028.8 noise)
IntegerSetLookup.DefaultHashSet 454450% (31501.3 noise)
==

Fixes https://github.com/dart-lang/sdk/issues/48641
TEST=ci

Change-Id: Id982e4aa30cd1d6a63f93c73917a8b921ad464a3
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/258600
Reviewed-by: Ryan Macnak <rmacnak@google.com>
Commit-Queue: Alexander Aprelev <aam@google.com>
2022-10-20 20:31:20 +00:00

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// Copyright (c) 2022, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
#ifndef RUNTIME_LIB_INTEGERS_H_
#define RUNTIME_LIB_INTEGERS_H_
#include "platform/globals.h"
namespace dart {
uint32_t Multiply64Hash(int64_t value);
} // namespace dart
#endif // RUNTIME_LIB_INTEGERS_H_