JNIEnv.Initialize optimization #3729

grendello · 2019-10-02T19:22:17Z

JNIEnv.Initialize is part of the Xamarin.Android runtime startup sequence and
it contributes a sizable chunk of time to it. Some code executed during startup
sequence wasn't as optimized as it could be and this commit aims to pick all the
low-hanging fruit in that area:

Don't use the Logger class.
This removes one class instantiation which wasn't absolutely necessary.
Calls to Logger are replaced with calls to a new native function
monodroid_log
Use native functions for timing.
It won't affect the user's code (unless it runs with timing enabled, of
course) but will allow our timing to be more precise and have less impact on
code performance. Implemented with two new native functions
monodroid_timing_start and monodroid_timing_stop
Remove calls to Environment.GetEnvironmentVariable
The calls took a non-trivial amount of time (around 4ms each) and were
replaced by putting the environment variables in libxamarin-app.so, in the
application environment configuration block.
Do not fully initialize UncaughtExceptionHandler during init
The handler's initialization is quite heavy while the handler itself is
going to be used only when there's an unhandled exception thrown. Delay full
initialization to the point in time when the handler is actually needed.
Avoid parsing of the PackageNamingPolicy enum values on runtime.
Instead, the desired value is placed in the application's environment
configuration block and simply cast from int to the enum.
Initialize Logger lazily.
The logging category is requested by Logger lazily instead of being set
from JNIEnv.Initialize. This allows the Logger class not to be
instantiated during startup.
Avoid static initialization of the Java.Interop.Runtime class.
Avoid heavy static initialization of the Java.Interop.TypeManager class.
This is done by initializing the type lookup dictionaries lazily, via
another "proxy" class.
Make Java class name lookup faster.
This is done by moving the lookup (and processing) to native code and
p/invoking the new monodroid_TypeManager_get_java_class_name function.

Other changes:

Remove dead code from JNIEnv
The JAVA_INTEROP symbol is always "defined" now, remove code used when it
was not defined.
Introduce fast performance measurement for managed code.
The timing code used by the native runtime is now exposed to the managed
land, thus allowing us fast and accurate (to the nanosecond level) timing
measurement.

Impact of the above changes on performance is summarized in the table below.

Device name: Pixel 3 XL
Device architecture: arm64-v8a
Number of test runs: 10

	Runtime init	Displayed	Notes
this commit	187.907	828.90	preload enabled; 32-bit build
master	218.804	852.70
this commit	154.718	803.50	preload disabled; 32-bit build
master	185.240	827.40
this commit	174.211	754.50	preload enabled; 64-bit build
master	201.779	783.20
this commit	144.158	741.80	preload disabled; 64-bit build
master	173.322	759.40

jonpryor · 2019-10-03T02:12:24Z

src/Mono.Android/Android.Runtime/JNIEnv.cs

@@ -29,7 +29,9 @@ struct JnienvInitializeArgs {
 		public int             localRefsAreIndirect;
 		public int             grefGcThreshold;
 		public IntPtr          grefIGCUserPeer;
-		public int             isRunningOnDesktop;


I wonder if this could possibly break the Designer... Just a rando fear.

Designer tests did fail in this build, although it doesn't appear to be related (but might be?):

1) Failed : Xamarin.AndroidDesigner.Tests.Moyeu.CanLoadLayoutsInProject /var/folders/24/8k48jl6d249_n_qfxwsl6xvm0000gn/T/ADT-0/RT-Moyeu-1/Moyeu/Resources/layout/InfoPaneLayout.axml Expected: no item equal to "MockView" But was: < "MockView" > First non-matching item at index [0]: "MockView" at Xamarin.AndroidDesigner.Tests.RegressionTest.CanLoadLayoutsInProject () [0x00000] in <055988ff4d7c4b6f95c58bd23af8596c>:0 at System.Runtime.CompilerServices.AsyncMethodBuilderCore+MoveNextRunner.InvokeMoveNext (System.Object stateMachine) [0x00000] in <208e3d8480c243b7804b22b6a5eb72fc>:0

And they failed again in the same way after reverting this change, so this is not the cause

jonpryor · 2019-10-03T02:13:16Z

src/Mono.Android/Android.Runtime/JNIEnv.cs

-		public int             isRunningOnDesktop;
+		public byte            isRunningOnDesktop;
+		public byte            brokenExceptionTransitions;
+		public PackageNamingPolicy packageNamingPolicy;


As this struct is shared with C++/libmonodroid.so, I think this field should properly be an int, and then we cast in JNIEnv.Initialize(). The cast should be optimized away to ~nothing.

jonpryor · 2019-10-03T02:14:37Z

src/Mono.Android/Android.Runtime/JNIEnv.cs

 		}

+		[DllImport ("__Internal")]
+		extern static void monodroid_log (LogLevel level, LogCategories category, string message);


At this point in time, it's "weird" to have this and the following methods declared when they're not actually used from C#. I imagine this will change in the future, but for now, this is weird.

The other two are used, this one was used instead of passing a string to monodroid_timing_{start,end} but it will still come useful IMO (I think it might be a good idea to replace Logger.Log calls with this in the code we ship)

jonpryor · 2019-10-03T02:16:10Z

src/Mono.Android/Android.Runtime/JNIEnv.cs

@@ -193,60 +177,34 @@ internal static unsafe void Initialize (JnienvInitializeArgs* args)

 			Mono.SystemDependencyProvider.Initialize ();

-#if JAVA_INTEROP
+			// TODO: env, javaVm, grefLoader, Loader_loadClass should all be obtained by AndroidRuntime constructor with p/invokes


Related: P/Invokes may be "fast", but let's not do one P/Invoke per value. Bundle them! Minimize P/Invoke transitions!

That's the plan :)

jonpryor · 2019-10-03T02:21:15Z

src/Mono.Android/Android.Runtime/Logger.cs

-		Error,
-		Fatal,
-		Silent
+		Unknown = 0x00,


Why the "noise"?

For that matter, why hex for values which aren't flags/bitfields?

The "noise" is to keep it explicit since the enum is "shared" with C++ - it's better to have the values stated clearly IMO. And why hex? I like the way hex numbers look, no other reason :)

jonpryor · 2019-10-03T02:23:26Z

src/Mono.Android/Java.Interop/TypeManager.cs

@@ -21,26 +21,6 @@ public static partial class TypeManager {

 		internal static IntPtr id_Class_getName;

-		static TypeManager ()


Relatedly, in this file, we want to remove the allocations on lines 19 & 20, as that will require JIT'ing Dictionary instantiations which we'd rather avoid if at all possible, especially on-device, when we shouldn't really need those fields at all. (Not needing them will require additional changes, but they shouldn't be needed...)

Yep, that's the next step here.

jonpryor · 2019-10-03T02:29:06Z

src/Xamarin.Android.Build.Tasks/Tasks/GeneratePackageManagerJava.cs

 			uint monoAOTMode = 0;
 			string androidPackageName = null;
 			var environmentVariables = new Dictionary<string, string> (StringComparer.Ordinal);
 			var systemProperties = new Dictionary<string, string> (StringComparer.Ordinal);

+			if (!Enum.TryParse (PackageNamingPolicy, out PackageNamingPolicy pnp)) {
+				pnp = PackageNamingPolicyEnum.LowercaseHash;


As of 88a1d6c, this should probably default to PackageNamingPolicy.LowercaseCrc64.

it was a copy-and-paste, oops. I'll change the default in the original location too, then (the default should be really specified somewhere else...)

jonpryor · 2019-10-03T02:29:59Z

src/Xamarin.Android.Build.Tasks/Xamarin.Android.Common.targets

@@ -120,11 +120,11 @@ Copyright (C) 2011-2012 Xamarin. All rights reserved.
 <!--
 *******************************************
  Extensibility hook that allows VS to
-  provide extra behavior without modifying 
+  provide extra behavior without modifying


Is there any way to avoid all of these whitespace changes?

Sure, in theory, they improve the code base. But it's making this PR really noisy.

The *.targets files (and some .cs too - like JNIEnv.cs) are often badly formatted and my editor removes trailing whitespace (as I want it to). I'll hand-edit the changes.

jonpryor · 2019-10-07T21:32:27Z

src/Mono.Android/Android.Runtime/Logger.cs

+
+		static Logger ()
+		{
+			lock (initLock) {


Is this strictly necessary? Static constructors will only ever be executed once, so this seems redundant.

jonpryor · 2019-10-10T13:30:19Z

src/Mono.Android/Android.Runtime/Logger.cs

@@ -58,18 +60,26 @@ internal static class Logger {
 					System.Console.WriteLine ("[{0}] {1}: {2}", level, appname, line);
 			}
 		}
+
+		[DllImport ("__Internal")]


Shouldn't this specify CallingConvention=CallingConvention.Cdecl?

jonpryor · 2019-10-10T13:40:11Z

src/Mono.Android/Android.Runtime/Logger.cs

+		static Logger ()
+		{
+			logCategories = (LogCategories) monodroid_get_log_categories ();
+		}
 	}

 	internal enum LogLevel {


If these need to be kept in-sync with libmonodroid, we should add an appropriate comment here, as was done with LogCategories.

jonpryor · 2019-10-10T13:42:54Z

src/Mono.Android/Java.Interop/TypeManager.cs

+		extern static IntPtr monodroid_TypeManager_get_java_class_name (IntPtr klass);
+
+		[DllImport ("__Internal", CallingConvention = CallingConvention.Cdecl)]
+		extern static void monodroid_free (IntPtr ptr);


AndroidEnvironment already has this P/Invoke declaration. We should make the AndroidEnvironment method internal, or move it to some shared location, instead of having two separate monodroid_free() declarations.

jonpryor · 2019-10-10T13:46:33Z

src/monodroid/jni/external-api.cc

+	timing->release_sequence (sequence);
+}
+
+MONO_API __stdcall const char*


I believe that this line should not have __stdcall anymore.

jonpryor · 2019-10-10T13:48:11Z

src/monodroid/jni/monodroid-glue.cc

-	MonoImage *image   = mono_assembly_get_image (assm);
+	MonoImage *image = mono_assembly_get_image  (assm);


The whitespace changes here are weird. Two spaces before (?

jonpryor · 2019-10-10T13:50:03Z

src/monodroid/jni/monodroid-glue.cc

@@ -1759,6 +1759,29 @@ MonodroidRuntime::Java_mono_android_Runtime_destroyContexts (JNIEnv *env, jclass
 	log_info (LOG_DEFAULT, "All domain cleaned up");
 }

+const char*


This should have a char* return type, not const char*, because the returned string should be free'd by the caller.

jonpryor · 2019-10-10T13:58:45Z

src/monodroid/jni/timing.hh

+		{
+			timing_diff diff (period);
+
+			log_debug_nocheck (LOG_TIMING, MESSAGE_FORMAT, message == nullptr ? "" : message, diff.sec, diff.ms, diff.ns);


Why the _nocheck variant here?

For that matter, why's it exist? I can't see any mention of Timing::debug in this PR. I do see Timing::info...

_nocheck is used because we always hide timing stuff behind a check if the timing category is enabled, so there's no point in re-checking it. And why it exists? Because I used it in test code and forgot to remove.

jonpryor · 2019-10-10T14:00:54Z

src/monodroid/jni/timing.hh

+		{
+			timing_diff diff (period);
+
+			log_info_nocheck (LOG_TIMING, MESSAGE_FORMAT, message == nullptr ? "" : message, diff.sec, diff.ms, diff.ns);


~Same question as with Timing::debug(): why the _nocheck variant? Currently all callers appear to check the log level before calling Timing::info before hand, but will that remain the case in the future?

Yes, this is the intention - that it will remain so in the future.

jonpryor · 2019-10-10T14:01:59Z

src/monodroid/jni/timing.hh

+				return;
+
+			std::lock_guard<std::mutex> lock (sequence_lock);
+			if (sequence->dynamic) {


Shouldn't this be done before lock is constructed? We don't need the mutex when sequence->dynamic is true.

If you do it before the lock you introduce a race condition

`JNIEnv.Initialize` is part of the Xamarin.Android runtime startup sequence and it contributes a sizable chunk of time to it. Some code executed during startup sequence wasn't as optimized as it could be and this commit aims to pick all the low-hanging fruit in that area: * Don't use the `Logger` class. This removes one class instantiation which wasn't absolutely necessary. Calls to `Logger` are replaced with calls to a new native function `monodroid_log` * Use native functions for timing. It won't affect the user's code (unless it runs with timing enabled, of course) but will allow our timing to be more precise and have less impact on code performance. Implemented with two new native functions `monodroid_timing_start` and `monodroid_timing_stop` * Remove calls to `Environment.GetEnvironmentVariable` The calls took a non-trivial amount of time (around 4ms each) and were replaced by putting the environment variables in `libxamarin-app.so`, in the application environment configuration block. * Do not fully initialize `UncaughtExceptionHandler` during init The handler's initialization is quite heavy while the handler itself is going to be used only when there's an unhandled exception thrown. Delay full initialization to the point in time when the handler is actually needed. * Avoid parsing of the `PackageNamingPolicy` enum values on runtime. Instead, the desired value is placed in the application's environment configuration block and simply cast from `int` to the enum. * Initialize `Logger` lazily. The logging category is requested by `Logger` lazily instead of being set from `JNIEnv.Initialize`. This allows the `Logger` class not to be instantiated during startup. * Avoid static initialization of the `Java.Interop.Runtime` class. * Avoid heavy static initialization of the `Java.Interop.TypeManager` class. This is done by initializing the type lookup dictionaries lazily, via another "proxy" class. * Make Java class name lookup faster. This is done by moving the lookup (and processing) to native code and p/invoking the new `monodroid_TypeManager_get_java_class_name` function. Other changes: * Remove dead code from `JNIEnv` The `JAVA_INTEROP` symbol is always "defined" now, remove code used when it was not defined. * Introduce fast performance measurement for managed code. The timing code used by the native runtime is now exposed to the managed land, thus allowing us fast and accurate (to the nanosecond level) timing measurement. Impact of the above changes on performance is summarized in the table below. Device name: **Pixel 3 XL** Device architecture: **arm64-v8a** Number of test runs: **10** | | **Runtime init** | **Displayed** | **Notes** | |-----------------|------------------|---------------|--------------------------------| | **this commit** | 187.907 | 828.90 | preload enabled; 32-bit build | | **master** | 218.804 | 852.70 | | | **this commit** | 154.718 | 803.50 | preload disabled; 32-bit build | | **master** | 185.240 | 827.40 | | | **this commit** | 174.211 | 754.50 | preload enabled; 64-bit build | | **master** | 201.779 | 783.20 | | | **this commit** | 144.158 | 741.80 | preload disabled; 64-bit build | | **master** | 173.322 | 759.40 | |

grendello added do-not-merge PR should not be merged. full-mono-integration-build For PRs; run a full build (~6-10h for mono bumps), not the faster PR subset (~2h for mono bumps) Area: App Runtime Issues in `libmonodroid.so`. labels Oct 2, 2019

grendello requested review from dellis1972, jonathanpeppers and jonpryor as code owners October 2, 2019 19:22

grendello self-assigned this Oct 2, 2019

grendello force-pushed the init-sequence-rework branch 2 times, most recently from 9358e3d to 6303191 Compare October 2, 2019 20:04

jonpryor reviewed Oct 3, 2019

View reviewed changes

grendello force-pushed the init-sequence-rework branch 5 times, most recently from d181b4c to 26110b8 Compare October 7, 2019 19:17

jonpryor reviewed Oct 7, 2019

View reviewed changes

grendello force-pushed the init-sequence-rework branch 3 times, most recently from 1dce36d to a6055e1 Compare October 8, 2019 12:04

grendello removed the do-not-merge PR should not be merged. label Oct 8, 2019

grendello changed the title ~~[WIP] JNIEnv.Initialize optimization~~ JNIEnv.Initialize optimization Oct 8, 2019

grendello added the do-not-merge PR should not be merged. label Oct 8, 2019

grendello force-pushed the init-sequence-rework branch from a6055e1 to d4951d5 Compare October 8, 2019 21:44

grendello force-pushed the init-sequence-rework branch 5 times, most recently from 4e670f6 to 2825067 Compare October 9, 2019 16:43

grendello removed the do-not-merge PR should not be merged. label Oct 9, 2019

jonpryor reviewed Oct 10, 2019

View reviewed changes

grendello force-pushed the init-sequence-rework branch from 2825067 to 85bcf1c Compare October 10, 2019 13:34

jonpryor reviewed Oct 10, 2019

View reviewed changes

grendello force-pushed the init-sequence-rework branch from 85bcf1c to 941ee78 Compare October 10, 2019 13:41

jonpryor reviewed Oct 10, 2019

View reviewed changes

grendello force-pushed the init-sequence-rework branch from 941ee78 to a63e496 Compare October 10, 2019 14:18

grendello force-pushed the init-sequence-rework branch from a63e496 to c6a4121 Compare October 10, 2019 14:52

jonpryor merged commit af02a65 into dotnet:master Oct 10, 2019

grendello deleted the init-sequence-rework branch October 10, 2019 21:09

jonpryor mentioned this pull request Nov 4, 2019

[C++ification] Take care of a few warnings and don't use LTO #3873

Merged

brendanzagaeski added this to the In Preview: 10.2 (d16-5) milestone Jan 23, 2020

github-actions bot locked and limited conversation to collaborators Jan 24, 2024

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

JNIEnv.Initialize optimization #3729

JNIEnv.Initialize optimization #3729

grendello commented Oct 2, 2019 •

edited

Loading

jonpryor Oct 3, 2019

grendello Oct 3, 2019

grendello Oct 4, 2019

jonpryor Oct 3, 2019

jonpryor Oct 3, 2019

grendello Oct 3, 2019

jonpryor Oct 3, 2019

grendello Oct 3, 2019

jonpryor Oct 3, 2019

grendello Oct 3, 2019

jonpryor Oct 3, 2019

grendello Oct 3, 2019

jonpryor Oct 3, 2019

grendello Oct 3, 2019

jonpryor Oct 3, 2019

grendello Oct 3, 2019 •

edited

Loading

jonpryor Oct 7, 2019

jonpryor Oct 10, 2019

jonpryor Oct 10, 2019

jonpryor Oct 10, 2019

jonpryor Oct 10, 2019

jonpryor Oct 10, 2019

jonpryor Oct 10, 2019

jonpryor Oct 10, 2019

grendello Oct 10, 2019

jonpryor Oct 10, 2019

grendello Oct 10, 2019

jonpryor Oct 10, 2019

grendello Oct 10, 2019

		@@ -21,26 +21,6 @@ public static partial class TypeManager {

		internal static IntPtr id_Class_getName;

		static TypeManager ()

		MonoImage *image = mono_assembly_get_image (assm);
		MonoImage *image = mono_assembly_get_image (assm);

JNIEnv.Initialize optimization #3729

JNIEnv.Initialize optimization #3729

Conversation

grendello commented Oct 2, 2019 • edited Loading

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

grendello Oct 3, 2019 • edited Loading

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

grendello commented Oct 2, 2019 •

edited

Loading

grendello Oct 3, 2019 •

edited

Loading