According to Vlad it's not necessary to set MONO_GC_PARAMS during AOT-
compilation, since all MONO_GC_PARAMS options can be changed at runtime:
Rolf Kvinge [16:35] @vlad.brezae is this true for all the different options MONO_GC_PARAMS take: https://github.com/xamarin/xamarin-macios/pull/1546#discussion_r97318092?
Rolf Kvinge [16:36] I remember this: https://bugzilla.xamarin.com/show_bug.cgi?id=35414#c14
Rofl Kvinge [16:36] which apparently you changed here, so that it can be changed at runtime: https://bugzilla.xamarin.com/show_bug.cgi?id=35414#c27
Rolf Kvinge [16:36] but I don't know if this is true for all the options you can pass using MONO_GC_PARAMS
Vlad Brezae [16:41] yes, it should be true for all of them, that was a bug
Rolf Kvinge [16:41] ok, that's great news 😄
Performance tests
-----------------
This is for a new watchOS extension project, built for release.
* The default (currently -O2) optimizations: 41s ( baseline ) 30.027.060 bytes ( baseline )
* All optimizations disabled (`--llvm-opt=all=`): 17s (-24s = -59%) 32.978.312 bytes (+2.951.252 = +10%)
* Optimized for size (`--llvm-opt=all=-Os`): 36s ( -5s = -12%) 28.617.408 bytes (-1.409.652 = -5%)
* Optimized for more size (`--llvm-opt=all=-Oz`): 35s ( -6s = -15%) 28.601.016 bytes (-1.426.044 = -5%)
* Optimized slightly (`--llvm-opt=all=-O1`): 35s ( -6s = -15%) 28.666.556 bytes (-1.360.504 = -5%)
* Optimized a lot (`--llvm-opt=all=-O3`): 41s ( 0s = 0%) 30.403.996 bytes (+ 376.936 = +1%)
Conclusions
-----------
* The fastest build by far (less than twice as fast) is if optimizations are
disabled, but this adds a 10% size penalty (~3 MB in this test case),
compared to the baseline, and 15% size penalty (4.3 MB) compared to -Oz.
* -Oz seems to have the best overall results: at least as fast as any other
optimized build, and the smallest app as well.
Caveats
-------
Some optimizations might not work the AOT compiled code. The resulting
binaries have not been tested.
Event sequence:
* mtouch is executed with the linker disabled.
* The linker pipeline copies all input assemblies (since the linker is
disabled the assemblies don't change) into the PreBuild directory. This will
keep the original timestamps of the input assemblies.
* mtouch is executed again, when none of the input assemblies changed.
* The linker pipeline will re-execute, because it will see that at least one
of the input assemblies (at least the .exe) is newer than at least one of
the assemblies in the PreBuild directory (usually a framework assembly,
because those have the original timestamp from their install location).
Fix:
Touch all the assemblies in the PreBuild directory after the linker pipeline
executes the first time. This way the second time mtouch is executed, it will
find that all assemblies in the PreBuild directory have timestamps later than
all the input assemblies, so it will load the cached linked assemblies,
instead of re-executing the linker pipeline.
Build extensions and the container app in the same mtouch process, by storing
all the mtouch arguments when called to build extensions in a text file, and
then reloading those arguments when called to build the main app.
This is required if we want to share code between extensions and the
container.
So that there can be multiple caches in the same process (which we'll have
once mtouch can compile extensions and the container app in the same process).
* [mtouch] Remove most static state and put it on an instance.
Remove most static state, and put it on an instance (of Application) instead.
Soon we'll build multiple apps (app extensions) in the same process, and we
need to make sure we're not inadvertedly (and incorrectly) sharing state
between apps, so remove as much static state as possible to avoid any
problems.
* [mtouch] Rename GetIsUsingClang -> IsUsingClang.
* [mtouch] Always require a SDK version when building.
Technically it was required before too, but the error messages were non-optimal:
it could for instance complain that the user is using an iOS framework that
was introduced in iOS 2.0.
* [mtouch tests] Rewrite MT0060 and MT0061 tests to use MTouchTool.
This makes sure we pass --sdk to mtouch (which MTouchTool does by default), so
that we don't run into MT0025 before the errors we're testing for.
The BundleId property is used by the code that generates the mSYM directory,
but its value was always the default value 'com.yourcompany.sample' instead of
looked up in the app's Info.plist.
So fix the BundleId property to do the expected.
Also fix the mSYM test (SymbolicationData) to actually test mSYM stuff (it was
partially disabled when we disabled automatic mSYM generation for C8, and
never re-enabled), and port it to the new and better test syntax, and add a
few more asserts to check the manifest.xml generation.
Run the partial static registrar separately for 32-bit and 64-bit, since this
is required with the upcoming changes to embed metadata tokens inside the
generated output, because the metadata tokens are different between the 32-bit
and 64-bit versions of Xamarin.iOS.dll.
Also make sure to properly resolve the 32-bit and 64-bit assemblies correctly
(by setting the ArchDirectory on the assembly resolver), so that we don't pick
up the reference assembly (which does not have the right metadata tokens).
Additionally stop running the partial static registrar for MonoTouch.Dialog-1,
since with the upcoming changes to use metadata tokens in the generated
output, we won't support registering anything more than once. This shouldn't
make much of an impact, because MonoTouch.Dialog-1 is fairly small, and
doesn't take long to register in the dynamic registrar. For device builds (or
when the static registrar is selected) this has no effect, since in that case
we're registering everythinga anyway.
Managed exception marshaling interferes with the debugger, because it adds
exception handlers to executing code, which makes the Mono runtime think an
exception is handled when logically it's not (although technically it is).
The consequence is that the IDEs will only be notified when we re-throw the
exception after catching it, making it impossible for the IDEs to stop when
the exception is thrown (they will instead stop when we re-throw the
exception).
So disable managed exception marshaling (unless the user changed the default
behavior) when a debugger is attached.
This is the same behavior as Xamarin.Android.
https://bugzilla.xamarin.com/show_bug.cgi?id=45116
Setting this option prints this to stdout:
> Mono Warning: option gen-compact-seq-points is deprecated.
and it's ignored, so just don't set this option.
* [tests] Remove Classic SDK tests.
* Remove XI/Classic support.
This also means we can remove support for the legacy registrars.
* [monotouch-test] Remove legacy registrar tests.
* [tests/mtouch] Remove Classic tests (and legacy registrar logic).
* [tests/scripted] Fix tests to reference Xamarin.iOS.dll.
Also bump maccore to get new test.
commit xamarin/maccore@eb9c34d875
Author: Rolf Bjarne Kvinge <rolf@xamarin.com>
Date: Fri May 13 12:46:04 2016 +0200
[monotouch-test] Add test to ensure mtouch properly links with CoreAudioKit when not using simlauncher.
mtouch only uses Xamarin.Mac to read plists, so change to use
our purely managed plist reader in Xamarin.MacDev instead.
That makes us able to change mtouch to be a normal command-line
executable (and project).
Which makes it logical to not mkbundle mtouch anymore,
it executes just fine with the system mono (and there's
no code to protect anymore either).
And since mmp and mtouch share some files, do the same
for mmp.
Rolf Bjarne Kvinge
Chris Hamons
Manuel de la Pena
Manuel de la Pena
Sebastien Pouliot