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[browser] improve default initial memory size (#80507)
make EmccInitialHeapSize dynamic based on size of the assemblies and AOT DATA segments Co-authored-by: Ankit Jain <radical@gmail.com>
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-9
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5 files changed

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-9
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‎src/mono/sample/wasm/browser-bench/Wasm.Browser.Bench.Sample.csproj

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@@ -9,10 +9,6 @@
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<EnableAggressiveTrimming Condition="'$(EnableAOTAndTrimming)' != ''">$(EnableAOTAndTrimming)</EnableAggressiveTrimming>
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<PublishTrimmed Condition="'$(EnableAOTAndTrimming)' != ''">$(EnableAOTAndTrimming)</PublishTrimmed>
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<RunAOTCompilation Condition="'$(EnableAOTAndTrimming)' != ''">$(EnableAOTAndTrimming)</RunAOTCompilation>
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<!-- the default heap size is ~512MB, which is too much because AppStart loads more copies
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of the wasm runtime and can leak a few of them. the result is that browser-bench's memory
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usage can climb as high as 3GB or more and then fail -->
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<EmccInitialHeapSize>83886080</EmccInitialHeapSize>
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</PropertyGroup>
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<ItemGroup>

‎src/mono/wasm/build/WasmApp.Native.targets

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<_EmccLinkRsp>$(_WasmIntermediateOutputPath)emcc-link.rsp</_EmccLinkRsp>
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<EmccInitialHeapSize Condition="'$(EmccInitialHeapSize)' == ''">$(EmccTotalMemory)</EmccInitialHeapSize>
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<EmccInitialHeapSize Condition="'$(EmccInitialHeapSize)' == ''">536870912</EmccInitialHeapSize>
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</PropertyGroup>
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<ItemGroup>
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<_EmccLDFlags Include="-s ASSERTIONS=$(_EmccAssertionLevelDefault)" Condition="'$(_WasmDevel)' == 'true'" />
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<_EmccLDFlags Include="@(_EmccCommonFlags)" />
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<_EmccLDSFlags Include="-Wl,--allow-undefined" />
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<_EmccLDSFlags Include="-s INITIAL_MEMORY=$(EmccInitialHeapSize)" />
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<!-- ILLinker should have removed unused imports, so error for Publish -->
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<_EmccLDSFlags Include="-s ERROR_ON_UNDEFINED_SYMBOLS=0" Condition="'$(WasmBuildingForNestedPublish)' != 'true'" />
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</ItemGroup>
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</Target>
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<Target Name="_WasmWriteRspFilesForLinking" DependsOnTargets="_CheckEmccIsExpectedVersion">
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<Target Name="_WasmCalculateInitialHeapSize"
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Condition="'$(EmccInitialHeapSize)' == ''"
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DependsOnTargets="_CheckEmccIsExpectedVersion">
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<ItemGroup>
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<_AOTObjectFile Include="%(_BitcodeFile.ObjectFile)" />
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</ItemGroup>
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<!-- for AOT builds we use llvm-size tool to collect size of the DATA segment in each object file -->
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<Exec Command="llvm-size$(_ExeExt) -d --format=sysv @(_AOTObjectFile, ' ')"
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Condition="'$(_WasmShouldAOT)' == 'true'"
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IgnoreStandardErrorWarningFormat="true"
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ConsoleToMsBuild="true"
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StandardOutputImportance="low" StandardErrorImportance="low"
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EnvironmentVariables="@(EmscriptenEnvVars)" >
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<Output TaskParameter="ConsoleOutput" ItemName="LlvmAotSizeOutput" />
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</Exec>
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<ItemGroup Condition="'$(_WasmShouldAOT)' == 'true'">
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<_AOTDataSegmentSize Condition="$([System.String]::Copy('%(LlvmAotSizeOutput.Identity)').StartsWith('DATA '))"
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Include="$([System.String]::Copy('%(LlvmAotSizeOutput.Identity)').Replace(&quot;DATA &quot;, &quot;&quot;).Replace(&quot; 0&quot;, &quot;&quot;).Trim())" />
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</ItemGroup>
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<WasmCalculateInitialHeapSize
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Assemblies="@(WasmAssembliesToBundle)"
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AOTDataSegmentSizes="@(_AOTDataSegmentSize)">
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<Output TaskParameter="InitialHeapSize" PropertyName="_WasmCalculatedInitialHeapSize" />
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</WasmCalculateInitialHeapSize>
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<PropertyGroup>
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<EmccInitialHeapSize Condition="'$(EmccInitialHeapSize)' == '' and '$(_WasmCalculatedInitialHeapSize)' != '' and $(_WasmCalculatedInitialHeapSize) > 16777216">$(_WasmCalculatedInitialHeapSize)</EmccInitialHeapSize>
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<EmccInitialHeapSize Condition="'$(EmccInitialHeapSize)' == ''">16777216</EmccInitialHeapSize>
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</PropertyGroup>
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</Target>
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<Target Name="_WasmWriteRspFilesForLinking" DependsOnTargets="_CheckEmccIsExpectedVersion;_WasmCalculateInitialHeapSize">
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<PropertyGroup>
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<_WasmEHLib Condition="'$(WasmEnableExceptionHandling)' == 'true'">libmono-wasm-eh-wasm.a</_WasmEHLib>
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<_WasmEHLib Condition="'$(WasmEnableExceptionHandling)' != 'true'">libmono-wasm-eh-js.a</_WasmEHLib>
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</PropertyGroup>
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<ItemGroup>
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<!-- order matters -->
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<_EmccLDSFlags Include="-s INITIAL_MEMORY=$(EmccInitialHeapSize)" />
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<_WasmNativeFileForLinking Include="%(_BitcodeFile.ObjectFile)" />
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<_WasmNativeFileForLinking Include="%(_WasmSourceFileToCompile.ObjectFile)" />
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‎src/mono/wasm/build/WasmApp.targets

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<Project>
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<UsingTask TaskName="WasmAppBuilder" AssemblyFile="$(WasmAppBuilderTasksAssemblyPath)" />
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<UsingTask TaskName="WasmLoadAssembliesAndReferences" AssemblyFile="$(WasmAppBuilderTasksAssemblyPath)" />
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<UsingTask TaskName="WasmCalculateInitialHeapSize" AssemblyFile="$(WasmAppBuilderTasksAssemblyPath)" />
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<!--
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Required public items/properties:
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- $(EmccFlags) - Emcc flags used for both compiling native files, and linking
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- $(EmccExtraLDFlags) - Extra emcc flags for linking
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- $(EmccExtraCFlags) - Extra emcc flags for compiling native files
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- $(EmccInitialHeapSize) - Initial heap size specified with `emcc`. Default value: 536870912
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- $(EmccInitialHeapSize) - Initial heap size specified with `emcc`. Default value: 16777216 or size of the DLLs, whichever is larger.
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Corresponds to `INITIAL_MEMORY` arg for emcc.
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(previously named EmccTotalMemory, which is still kept as an alias)
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‎src/mono/wasm/wasm.proj

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<PropertyGroup>
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<_EmccExportedRuntimeMethods>&quot;[@(EmccExportedRuntimeMethod -> '%27%(Identity)%27', ',')]&quot;</_EmccExportedRuntimeMethods>
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<_EmccExportedFunctions>@(EmccExportedFunction -> '%(Identity)',',')</_EmccExportedFunctions>
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<EmccInitialHeapSize>536870912</EmccInitialHeapSize>
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<EmccInitialHeapSize>16777216</EmccInitialHeapSize>
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</PropertyGroup>
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<ItemGroup>
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<_EmccLinkFlags Include="-s INITIAL_MEMORY=$(EmccInitialHeapSize)" />

‎src/tasks/WasmAppBuilder/WasmCalculateInitialHeapSize.cs

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// Licensed to the .NET Foundation under one or more agreements.
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// The .NET Foundation licenses this file to you under the MIT license.
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using System;
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using System.IO;
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using Microsoft.Build.Framework;
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using Microsoft.Build.Utilities;
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namespace Microsoft.WebAssembly.Build.Tasks;
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/// <summary>estimate the total memory needed for the assemblies and AOT data segments.</summary>
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public class WasmCalculateInitialHeapSize : Task
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{
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[Required]
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public string[] Assemblies { get; set; } = Array.Empty<string>();
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public string[] AOTDataSegmentSizes { get; set; } = Array.Empty<string>();
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[Output]
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public long InitialHeapSize { get; private set; }
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public override bool Execute()
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{
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long totalDllSize = 0;
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long totalDataSize = 0;
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foreach (string asm in Assemblies)
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{
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var info = new FileInfo(asm);
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if (!info.Exists)
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{
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Log.LogError($"Could not find assembly '{asm}'");
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return false;
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}
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totalDllSize += info.Length;
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}
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// during non-AOT builds, AOTDataSegmentSizes is empty
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foreach (string segment in AOTDataSegmentSizes)
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{
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if (!long.TryParse(segment, out long segmentSize))
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{
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Log.LogError($"Could not parse AOT Data segment size '{segment}");
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return false;
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}
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totalDataSize += segmentSize;
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}
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// this is arbitrary guess about memory overhead of the runtime, after the assemblies are loaded
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const double extraMemoryRatio = 1.2;
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// plus size of data segments generated by AOT
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long memorySize = totalDataSize + (long)(totalDllSize * extraMemoryRatio);
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// round it up to 64KB page size for wasm
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InitialHeapSize = (memorySize + 0x10000) & 0xFFFF0000;
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return true;
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}
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}

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