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[JavaCallableWrappers] avoid string.Format() - #1061
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Running PerfView on Windows in a .NET MAUI app, I can see this taking
up time inside the `<GenerateJavaStubs/>` MSBuild task:
| Name | Inc % | Inc |
| --- | --: | --: |
| java.interop.tools.javacallablewrappers!Java.Interop.Tools.JavaCallableWrappers.JavaCallableWrapperGenerator..ctor() | 1.4 | 51 |
| mscorlib.ni!String.Format | 1.0 | 35 |
Around ~26ms appear to be spent inside `JavaCallableWrapperGenerator`
doing `string.Format()`.
Reviewing the code, there is quite a bit of `WriteLine()` used along
with format arguments. I could rework this to use string
interpolation, which would be slightly better -- as the C# compiler
could replace many of these with `string.Concat()`.
However, the best case is to just call `Write()` with individual
strings, so we don't do extra work creating intermediate string
values.
Copying `Java.Interop.Tools.JavaCallableWrappers.dll` to:
C:\Program Files\dotnet\packs\Microsoft.Android.Sdk.Windows\33.0.4\tools
It appears to save about ~17ms in a `dotnet new maui` project:
Top 10 most expensive tasks
--GenerateJavaStubs = 795 ms
++GenerateJavaStubs = 812 ms
This was an incremental build with a `.xaml` change.
jonpryor
reviewed
Dec 5, 2022
| for (int i = 0; i < children.Count; ++i) { | ||
| string methods = string.Format ("__md_{0}_methods", i + 1); | ||
| GenerateRegisterType (writer, children [i], methods); | ||
| GenerateRegisterType (writer, children [i], $"__md_{i + 1}_methods"); |
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While I can see multiple .Write() calls being faster -- and that makes up the majority of this PR -- are format strings actually faster than string.Format()?
For a quick one-off, it looks like the IL for these two statements is identical:
int i = 1;
var s1 = string.Format ("__md_{0}_methods", i);
var s2 = $"__md_{i}_methods";Both s1 and s2 become string.Format() calls. Thus, this doesn't appear to be a significant change.
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Were you testing .NET 7?
The second one does this for me:
DefaultInterpolatedStringHandler defaultInterpolatedStringHandler = new DefaultInterpolatedStringHandler(13, 1);
defaultInterpolatedStringHandler.AppendLiteral("__md_");
defaultInterpolatedStringHandler.AppendFormatted(i);
defaultInterpolatedStringHandler.AppendLiteral("_methods");
Console.WriteLine(defaultInterpolatedStringHandler.ToStringAndClear());It seems like you might also need to use s1/s2.
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jonpryor
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Dec 12, 2022
Changes: dotnet/java-interop@3a9f770...149d70f * dotnet/java-interop@149d70fe: [generator] Refactor enum writing to use SourceWriters (dotnet/java-interop#1063) * dotnet/java-interop@c2daa9f0: [Java.Interop.Tools.Cecil] DirectoryAssemblyResolver & File.Exists() (dotnet/java-interop#1065) * dotnet/java-interop@8ab9d33a: [Java.Interop.Tools.TypeNameMappings] improve `ToJniNameFromAttributesForAndroid` (dotnet/java-interop#1064) * dotnet/java-interop@09f8da26: [JavaCallableWrappers] avoid `string.Format()` (dotnet/java-interop#1061) Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
jonathanpeppers
added a commit
that referenced
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Jan 5, 2023
Running PerfView on Windows in a .NET MAUI app, I can see this taking up time inside the `<GenerateJavaStubs/>` MSBuild task: | Name | Inc % | Inc | | --------------------------------------------------------------------------------------------------------------------- | ----: | ----: | | java.interop.tools.javacallablewrappers!Java.Interop.Tools.JavaCallableWrappers.JavaCallableWrapperGenerator..ctor() | 1.4 | 51 | | mscorlib.ni!String.Format | 1.0 | 35 | Around ~26ms appears to be spent inside `JavaCallableWrapperGenerator` calling `string.Format()`. Reviewing the code, there is quite a bit of `WriteLine()` used along with format arguments. I could rework this to use string interpolation, which would be slightly better, as the C# compiler could replace many of these with `string.Concat()`. However, the best case is to just call `Write()` with individual strings, so we don't do extra work creating intermediate string values. Copying `Java.Interop.Tools.JavaCallableWrappers.dll` to: C:\Program Files\dotnet\packs\Microsoft.Android.Sdk.Windows\33.0.4\tools It appears to save about ~17ms in a `dotnet new maui` project: Top 10 most expensive tasks --GenerateJavaStubs = 795 ms ++GenerateJavaStubs = 812 ms This was an incremental build with a `.xaml` change.
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Running PerfView on Windows in a .NET MAUI app, I can see this taking up time inside the
<GenerateJavaStubs/>MSBuild task:Around ~35ms appear to be spent inside
JavaCallableWrapperGeneratordoingstring.Format().Reviewing the code, there is quite a bit of
WriteLine()used along with format arguments. I could rework this to use string interpolation, which would be slightly better -- as the C# compiler could replace many of these withstring.Concat().However, the best case is to just call
Write()with individual strings, so we don't do extra work creating intermediate string values.Copying
Java.Interop.Tools.JavaCallableWrappers.dllto:It appears to save about ~17ms in a
dotnet new mauiproject:This was an incremental build with a
.xamlchange.