[Xamarin.Android.Build.Tasks] parse JDK release file directly
#8663
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Fixes: dotnet#8369 During Android project builds, the `<ValidateJavaVersion/>` MSBuild task currently shells out to `java -version` and `javac -version` to determine if we have a *valid* & usable JDK. Unfortunately, some customer logs have reported build times that are completely bananas: Task ValidateJavaVersion 23.469s ... Top 10 most expensive tasks ... ValidateJavaVersion = 3:46.740, 35 calls `java -version` and/or `javac -version` must be quite slow! Reading the source for OpenJDK, it appears that `java -version` actually starts a JVM to call a single method: * https://github.com/openjdk/jdk/blob/df370d725e5ae55a05479e8375bf665233ac3e44/src/java.base/share/native/libjli/java.c#L1895-L1913 * https://github.com/openjdk/jdk/blob/c9cacfb25d1f15c879c961d2965a63c9fe4d9fa7/src/java.base/share/classes/java/lang/VersionProps.java.template#L191-L233 That could explain the slowness? To improve this, let's just parse the file: * C:\Program Files\Microsoft\jdk-11.0.19.7-hotspot\release With contents: IMPLEMENTOR="Microsoft" IMPLEMENTOR_VERSION="Microsoft-7621296" JAVA_VERSION="11.0.19" JAVA_VERSION_DATE="2023-04-18" LIBC="default" MODULES="java.base java.compiler java.datatransfer java.xml java.prefs java.desktop java.instrument java.logging java.management java.security.sasl java.naming java.rmi java.management.rmi java.net.http java.scripting java.security.jgss java.transaction.xa java.sql java.sql.rowset java.xml.crypto java.se java.smartcardio jdk.accessibility jdk.internal.vm.ci jdk.management jdk.unsupported jdk.internal.vm.compiler jdk.aot jdk.internal.jvmstat jdk.attach jdk.charsets jdk.compiler jdk.crypto.ec jdk.crypto.cryptoki jdk.crypto.mscapi jdk.dynalink jdk.internal.ed jdk.editpad jdk.hotspot.agent jdk.httpserver jdk.internal.le jdk.internal.opt jdk.internal.vm.compiler.management jdk.jartool jdk.javadoc jdk.jcmd jdk.management.agent jdk.jconsole jdk.jdeps jdk.jdwp.agent jdk.jdi jdk.jfr jdk.jlink jdk.jshell jdk.jsobject jdk.jstatd jdk.localedata jdk.management.jfr jdk.naming.dns jdk.naming.ldap jdk.naming.rmi jdk.net jdk.pack jdk.rmic jdk.scripting.nashorn jdk.scripting.nashorn.shell jdk.sctp jdk.security.auth jdk.security.jgss jdk.unsupported.desktop jdk.xml.dom jdk.zipfs" OS_ARCH="x86_64" OS_NAME="Windows" SOURCE=".:git:6171c19d2c18" We can just call `StreamReader.ReadLine()` until `JAVA_VERSION="` is found. I kept the existing logic in place, with an escape hatch if it were ever needed. After a few .NET 9 previews, we could consider removing old logic entirely? This logic is considerably faster, because we no longer launch a JVM! * Before: Task ValidateJavaVersion 377ms * After: Task ValidateJavaVersion 2ms Where you can test the "Before" logic by passing `-p:_AndroidUseJavaExeVersion=true`. I assume the customer's log from before (35 calls) would be around 70ms give or take instead of 3 hours and 46 minutes? Even if this estimation was 10x worse, it would still be a huge improvement! :eyes:
I might have misread and this is 3 minutes 46 seconds |
dellis1972
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* main: LEGO: Merge pull request 8665 [Xamarin.Android.Build.Tasks] parse JDK `release` file directly (#8663)
grendello
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Jan 25, 2024
* main: Localized file check-in by OneLocBuild Task (#8668) [Xamarin.Android.build.Tasks] `<CheckDuplicateJavaLibraries/>` ignores `repackaged.jar` (#8664) LEGO: Merge pull request 8665 [Xamarin.Android.Build.Tasks] parse JDK `release` file directly (#8663) Bump to dotnet/installer@f91d4ca399 9.0.100-alpha.1.24070.3 (#8635) [.github] Re-enable locking issues after 30 days of inactivity (#8655) Localized file check-in by OneLocBuild Task (#8657) LEGO: Merge pull request 8656 Localized file check-in by OneLocBuild Task (#8652) Bump to xamarin/xamarin-android-tools/main@b175674 (#8644) [Xamarin.Android.Build.Tasks] remove checks for `$(UsingAndroidNETSdk)` (#8647) [Xamarin.Android.Build.Tasks] XA1039 error for Android.Support (#8629)
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Fixes: #8369
During Android project builds, the
<ValidateJavaVersion/>MSBuild task currently shells out tojava -versionandjavac -versionto determine if we have a valid & usable JDK.Unfortunately, some customer logs have reported build times that are completely bananas:
java -versionand/orjavac -versionmust be quite slow! Reading the source for OpenJDK, it appears thatjava -versionactually starts a JVM to call a single method:That could explain the slowness?
To improve this, let's just parse the file:
With contents:
We can just call
StreamReader.ReadLine()untilJAVA_VERSION="is found.I kept the existing logic in place, with an escape hatch if it were ever needed. After a few .NET 9 previews, we could consider removing old logic entirely?
This logic is considerably faster, because we no longer launch a JVM!
Where you can test the "Before" logic by passing
-p:_AndroidUseJavaExeVersion=true.I assume the customer's log from before (35 calls) would be around 70ms give or take instead of 3 hours and 46 minutes? Even if this estimation was 10x worse, it would still be a huge improvement! 👀