[monodroid, Xamarin.Android.Build.Tasks] Interpreter support (#4618) #4618

grendello · 2020-04-24T19:20:18Z

Context: https://www.mono-project.com/news/2017/11/13/mono-interpreter/

Add experimental support to use Mono's IL interpreter instead
of using the JIT or (Hybrid)AOT backends by setting the
$(_AndroidUseInterpreter) MSBuild property to True.

This is a proof-of-concept to explore how the interpreter backend
performs compared to the JIT backend at various tasks. It is not
currently intended for production use.

Note that Mono's IL interpreter does not currently support running
on x86 targets. Issue an XA0124 error if the interpreter is enabled
when targeting x86 devices.

One "interesting" -- but not explored -- result is that startup time
is reduced when using the interpreter; on a Pixel 3 XL launching
a arm64-v8a build of tests/Xamarin.Forms-Performance-Integration:

Description	native-to-managed	Runtime.init	ActivityDisplayed
JIT	53.660 ms	92.821 ms	1091.30 ms
Interpreter	32.019 ms	112.288 ms	897.50 ms

Here, native-to-managed time and ActivityDisplayed times are reduced,
while Runtime.init() time is increased.

We did not explore why this would be the case, or what other
performance changes would be present after app startup.

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

jonpryor · 2020-04-27T16:37:59Z

$(_AndroidUseInterpreter) is a "private" property. The question: what property & semantics should we have for this to be public?

Options:

Make it public: $(AndroidUseInterpreter) boolean property
Add to $(AndroidAotMode)?
New enum property: $(AndroidRuntimeModes)
Something else?

`$(AndroidAotMode)`

$(AndroidAotMode) is an "enum" property with the values: None, Normal, Hybrid, Full. Could we add an Interpreter value?

While this could be done, it was felt that this was exposing an "implementation detail" -- that while an "interpreter" value is used with mono_jit_set_aot_mode(), that need not be the case for all time.

The other problem is that we'll invariably want to be able to specify both interpreter and an AOT mode. A separate $(AndroidUseInterpreter) property works, or we could turn $(AndroidAotMode) into a comma-separated "flags enum" property as described in $(AndroidRuntimeModes).

`$(AndroidRuntimeModes)`

A possible scenario with more "robust" interpreter support is that Mono could support "tiered JIT" use: interpreter for starters, then JIT frequently used methods.

This suggests we could have a "[Flags]-enum like" comma-separated property value, being one or more of:

Aot
Jit
Interpreter

This allows combinations of:

Aot: $(AndroidAotMode)=Full [not currently supported]
Jit: aka $(AndroidAotMode)=None [or Normal?]; current default.
Interpreter: only interpreter, no JIT
Interpreter,Jit: Tiered JIT use, if/when that is ever supported.
Aot,Jit: $(AndroidAotMode)=Normal or Hybrid [ambiguous; suggests this entire idea needs more thought]
Aot,Interpreter: $(AndroidAotMode)=Normal or Hybrid [also ambiguous]
Aot,Interpreter,Jit: All The Things! Not sure if this combination actually makes sense, but if it did, it would be tiered JIT for non-AOT'd methods.

On the one hand, this could plausibly "subsume" $(AndroidAotMode) allowing for a nice "semantic cleanup," but on the other hand such "subsume-ation" makes for potential confusion about priority and ordering of properties when both $(AndroidRuntimeModes) and $(AndroidAotMode) are set. It also contains ambiguities around Hybrid vs. Full AOT.

grendello · 2020-04-27T16:49:44Z

@jonp I'd use $(AndroidUseInterpreter) as it doesn't expose any technicalities to the users.

lewurm · 2020-04-28T07:49:23Z

build-tools/xaprepare/xaprepare/ConfigAndData/Runtimes.cs

+				abiName: AbiNames.TargetJit.AndroidX86,
+				interpreter: true,
+				enabledCheck: (Context ctx) => ctx.IsTargetJitAbiEnabled (AbiNames.TargetJit.AndroidX86)
+			),


Alas we do not support the interpreter on x86.

Is this fairly common? Or does everyone use x86_64 anyway as emulator?

Edit: I just saw we ship the x86 interpreter bits in the Mono SDK 😅 that will assert on startup though.

We actually use x86 emulators on CI...

I meant with "everyone" the average Xamarin.Android developer 🙂

Developers will most definitely run emulators using either x86 or x86_64 images, but I don't know which one of those is more popular. Both are accelerated and x86_64 can run x86 apps, so I'd hope that this one's more popular, but that's just my hope not supported by any data :)

ok, I created mono/mono#19669

I think most devs use x86 right now as Visual Studio suggests it by default.

@lewurm x86 is like 90% with x86_64 in the < 10% range. ARM even lower here.

ABI/CPU -

88/10/3/2% for x86/x86_64/armeabi-v7a/arm64-v8a on Mac.

90/7/1/1% for x86/x86_64/armeabi-v7a/arm64-v8a on Windows.

src/monodroid/jni/android-system.hh

Doesn't work yet - XA runtime is not placed in the `interpreter-` dirs yet

Context: https://www.mono-project.com/news/2017/11/13/mono-interpreter/ Add *experimental* support to use [Mono's IL interpreter][0] instead of using the JIT or (Hybrid)AOT backends by setting the `$(_AndroidUseInterpreter)` MSBuild property to True. This is a proof-of-concept to explore how the interpreter backend performs compared to the JIT backend at various tasks. It is not currently intended for production use. Note that Mono's IL interpreter does *not* currently support running on x86 targets. Issue an XA0124 error if the interpreter is enabled when targeting x86 devices. One "interesting" -- but not explored -- result is that startup time is [*reduced* when using the interpreter][1]; on a Pixel 3 XL launching a arm64-v8a build of `tests/Xamarin.Forms-Performance-Integration`: | Description | native-to-managed | Runtime.init | ActivityDisplayed | |------------:|------------------:|-------------:|------------------:| | JIT | 53.660 ms | 92.821 ms | 1091.30 ms | | Interpreter | 32.019 ms | 112.288 ms | 897.50 ms | Here, native-to-managed time and ActivityDisplayed times are reduced, while `Runtime.init()` time is increased. We did not explore why this would be the case, or what other performance changes would be present after app startup. [0]: https://www.mono-project.com/news/2017/11/13/mono-interpreter/ [1]: https://gist.github.com/grendello/3510f2c0621eb360cd063d6c00b4b1e8#file-results-md

grendello requested review from jonathanpeppers, pjcollins, dellis1972 and jonpryor April 24, 2020 19:20

grendello force-pushed the interpreter branch 2 times, most recently from b973b9c to 19fcbca Compare April 27, 2020 12:17

grendello marked this pull request as ready for review April 27, 2020 14:55

dellis1972 reviewed Apr 27, 2020

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lewurm reviewed Apr 28, 2020

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grendello force-pushed the interpreter branch 5 times, most recently from 1452d6e to 48e0302 Compare April 28, 2020 12:53

grendello requested a review from brendanzagaeski as a code owner April 28, 2020 12:53

lewurm mentioned this pull request Apr 28, 2020

[interpreter] add x86 support mono/mono#19669

Closed

[WIP] Interpreted apps

e2f5915

Doesn't work yet - XA runtime is not placed in the `interpreter-` dirs yet

grendello force-pushed the interpreter branch from 48e0302 to e2f5915 Compare April 28, 2020 17:22

jonathanpeppers approved these changes Apr 28, 2020

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jonpryor merged commit 42822e0 into dotnet:master Apr 28, 2020

grendello changed the title ~~[WIP] Interpreted apps~~ [monodroid, Xamarin.Android.Build.Tasks] Interpreter support (#4618) Apr 28, 2020

grendello deleted the interpreter branch April 28, 2020 20:59

brendanzagaeski added this to the In Preview: 10.4 (d16-7) milestone Jun 3, 2020

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[monodroid, Xamarin.Android.Build.Tasks] Interpreter support (#4618) #4618

[monodroid, Xamarin.Android.Build.Tasks] Interpreter support (#4618) #4618

grendello commented Apr 24, 2020 •

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jonpryor commented Apr 27, 2020

grendello commented Apr 27, 2020

lewurm Apr 28, 2020 •

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grendello Apr 28, 2020

lewurm Apr 28, 2020

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jonathanpeppers Apr 28, 2020

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JonDouglas Apr 28, 2020

[monodroid, Xamarin.Android.Build.Tasks] Interpreter support (#4618) #4618

[monodroid, Xamarin.Android.Build.Tasks] Interpreter support (#4618) #4618

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grendello commented Apr 24, 2020 • edited Loading

jonpryor commented Apr 27, 2020

$(AndroidAotMode)

$(AndroidRuntimeModes)

grendello commented Apr 27, 2020

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grendello commented Apr 24, 2020 •

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`$(AndroidAotMode)`

`$(AndroidRuntimeModes)`

lewurm Apr 28, 2020 •

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JonDouglas Apr 28, 2020 •

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