[mono] Extend mono AOT compiler to ingest .mibc profiles #70194

mdh1418 · 2022-06-03T05:42:49Z

In effort to bring back Profiled Ahead-Of-Time compilation on Mono through leveraging EventPipe diagnostics-tracing and CoreCLR's dotnet-pgo tool, this PR enables Mono's AOT Compiler to directly consume a .mibc (Managed Instrumented Block Counts) Portable Executable file generated through dotnet-pgo for the purpose of AOT compiling methods traced during an app run.

This follows the work to emit MethodDetails and BulkType events on the mono runtime, which was imperative to know exactly which methods were encountered during an app run.

Prior Profiled AOT .aotprofile processing

Mono's AOT Compiler (mono-sgen) prior Profiled AOT story involved a .aotprofile file which recorded identifying components of methods, embedded types, generic instantiations of methods/types, and the overarching modules https://github.com/mono/mono/tree/main/mcs/class/Mono.Profiler.Log/Mono.Profiler.Aot. The compiler, when compiling particular assemblies, would leverage .aotprofile data to determine which methods to AOT compile by:

Loading the data into ProfileData structs
Resolving the ProfileData structs into the corresponding images, classes, generic instantiations, and methods within the assemblies loaded through the compiler
Adding the .aotprofile methods with some filtering to a particular assembly's (X.dll) AOT image (X.dll.so/X.dll.dylib/other native extensions) if they are inherently from that assembly, or related to that assembly. (e.g. method List<Q>.ToArray() where List is in System.Private.CoreLib.dll, but Q is in Q.dll, the method is related to assembly Q.dll)

.aotprofile example

Proposed Profiled AOT .mibc processing

The .mibc file format as a Portable Executable already contains comprehensive information of traced methods (as a result of MethodDetails and BulkType events from #68571). As such, there is no need to neither generate nor load ProfileData structs. Instead, we:

Leverage .mibc's AssemblyDictionary global function to obtain each mibcGroupMethod - add_mibc_profile_methods
Iterate through each method entry within a mibcGroupMethod - add_mibc_group_method_methods
Add individual .mibc methods using the same filter and method addition used when processing .aotprofile - add_single_mibc_profile_method

.mibc from HelloWorld mono sample
Breakdown of HelloWorld Sample .mibc file

This PR makes the following changes:

Introduces .mibc profile file into the mono AOT compilation pipeline
Extends mono's image handling to allow for loading MemberRefs from non executable images and replace boolean image open/load options with MonoImage(Open/Load)Options structs for scalability
Bootstrap the MonoAOTCompiler to use the introduced .mibc processing

Using the mono-sgen compiler to process .mibc

./build -s mono+libs -os <OS> -arch <arch> -c <config>
MONO_LOG_MASK=asm MONO_LOG_LEVEL=debug MONO_PATH=./artifacts/bin/HelloWorld/arm64/Release/osx-arm64/publish/ artifacts/obj/mono/OSX.arm64.Release/out/bin/mono-sgen --aot=profile-only,mibc-profile=/Users/mihw/runtime_two/HelloWorld_arm64.mibc artifacts/bin/HelloWorld/arm64/Release/osx-arm64/publish/System.Console.dll artifacts/bin/HelloWorld/arm64/Release/osx-arm64/publish/System.Private.CoreLib.dll artifacts/bin/HelloWorld/arm64/Release/osx-arm64/publish/HelloWorld.dll

…ef in .mibc files

dotnet-issue-labeler · 2022-06-03T05:42:52Z

I couldn't figure out the best area label to add to this PR. If you have write-permissions please help me learn by adding exactly one area label.

lambdageek

Looking good.

Couple of things i'd like to see changed:

let's do some cleanup in image.c
let's make the code that iterates over the mibc group a bit more aware of the format
instead of copy/pasting the AOT "related methods" logic, extract it into a function and share between the mibc and legacy aot profiler

src/mono/mono/metadata/assembly.c

src/mono/mono/metadata/image.c

src/mono/mono/metadata/metadata-internals.h

src/mono/mono/mini/aot-compiler.c

lambdageek

LGTM. A couple of nits, some portability improvements, and a bit more image_open refactoring suggestions

src/mono/mono/mini/aot-compiler.c

lambdageek · 2022-06-06T14:05:32Z

src/mono/mono/mini/aot-compiler.c

+			continue;
+
+		g_assert (opcodeIp + 4 < opcodeEnd);
+		guint32 token = *(guint32 *)(opcodeIp + 1);


Suggested change

guint32 token = *(guint32 *)(opcodeIp + 1);

guint32 token = read32 (opcodeIp + 1);

Thanks! I thought it would work, but convinced myself it didnt when xcode lldb complained about expr read32 (opcodeIp + 1). Is there a way to have the xcode lldb recognize methods such as read32?

I think if you compile the runtime with "enough" debug information (maybe -g3) then debuggers ought to recognize macros like read32. not sure if that really works with clang+lldb

src/mono/mono/metadata/image-internals.h

mdh1418 · 2022-06-06T21:20:38Z

The failures are unrelated to this PR and have issues created.

lateralusX · 2022-06-07T07:17:26Z

src/mono/mono/metadata/image-internals.h

@@ -9,6 +9,17 @@
 #include <mono/metadata/image.h>
 #include <mono/metadata/loader-internals.h>

+typedef struct {
+	int dont_care_about_cli : 1;


Any specific reason why these parameters where inverted compared to the arguments passed to functions below?

Any particular win to use bit fields for this? I think it would be much clearer to use bool type instead, it would also make the init code more clear.

Any specific reason why these parameters where inverted compared to the arguments passed to functions below?

Turns out most of the time we care about cli and pecoff, so the callers become a bit simpler: they can just initialize the options struct to zero.

Any particular win to use bit fields for this? I think it would be much clearer to use bool type instead, it would also make the init code more clear.

I think I suggested bitfields more out of habit than any rational reason. These could be booleans.

Thanks! I'll modify these to a boolean type in the upcoming PR

(the MonoImage:not_executable we do want to keep in a bitfield - we try to keep the size of that structure down)

This is now in PR #71657 @lateralusX @lambdageek

mdh1418 added 3 commits June 3, 2022 01:36

[mono] Add non_executable field to MonoImage to properly load MethodR…

7038cbe

…ef in .mibc files

[mono][aot] Extend mono-aot-compiler to handle .mibc profile

46d2e03

[tasks] Extend MonoAOTCompiler task to handle .mibc profiles

406ced3

mdh1418 requested review from vargaz, lambdageek, SamMonoRT, thaystg and marek-safar as code owners June 3, 2022 05:42

ghost assigned mdh1418 Jun 3, 2022

mdh1418 marked this pull request as draft June 3, 2022 05:44

mdh1418 mentioned this pull request Jun 3, 2022

[mono] Profiled AOT - PGO tracking #69512

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6 tasks

teo-tsirpanis added the area-Codegen-AOT-mono label Jun 3, 2022

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mdh1418 requested review from tommcdon, steveisok and lateralusX June 3, 2022 16:04

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mdh1418 marked this pull request as ready for review June 3, 2022 19:08

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mdh1418 force-pushed the mono_aot_compiler_ingest_mibc branch from e636d86 to 15372c2 Compare June 3, 2022 21:12

mdh1418 added 2 commits June 3, 2022 23:35

Address feedback

7428239

Add method descriptions

b1fb61e

mdh1418 force-pushed the mono_aot_compiler_ingest_mibc branch from 15372c2 to b1fb61e Compare June 4, 2022 03:35

lambdageek approved these changes Jun 6, 2022

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Address more feedback

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lambdageek approved these changes Jun 6, 2022

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This was referenced Jun 6, 2022

Assert failure: m_alignpad == 0 in libraries tests #70231

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[wasm] DebuggerTests.EvaluateOnCallFrameTests.EvaluateExpressionsWithElementAccessByLocalVariable Failed #70310

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mdh1418 merged commit 2b21dcd into dotnet:main Jun 6, 2022

mdh1418 deleted the mono_aot_compiler_ingest_mibc branch June 6, 2022 21:20

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mdh1418 mentioned this pull request Jun 16, 2022

[mono] Extend MonoAOTCompiler Task #70851

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Integrate mibc mono config extension #71657

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Support for Android "Profiled AOT" in .NET 6 #56989

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[mono] Extend mono AOT compiler to ingest .mibc profiles #70194

[mono] Extend mono AOT compiler to ingest .mibc profiles #70194

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	guint32 token = (guint32 )(opcodeIp + 1);
	guint32 token = read32 (opcodeIp + 1);

[mono] Extend mono AOT compiler to ingest .mibc profiles #70194

[mono] Extend mono AOT compiler to ingest .mibc profiles #70194

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mdh1418 commented Jun 3, 2022 • edited Loading

Prior Profiled AOT .aotprofile processing

Proposed Profiled AOT .mibc processing

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