Runtime Performance Ideas

Runtime performance is important for our users. We care about the startup performance and also the performance in general.

Measurements

Type of measurements we use to analyze the runtime performance

• Regular test measurements with time and size plots

• Profiler - we use manual measurements with profiler to analyze the performance of the managed code. Usually the calls, alloc and sample reports.

  • NDK native profiler can be used to profile Mono + Xamarin.Android native runtimes

Ideas

• New JNI marshal methods to speedup startup by avoiding System.Reflection.Emit use. That would hopefully provide faster marshal methods registration and reduce the JIT time and apk size

• Profiled AOT - the idea is to AOT just the startup code to make apk size smaller, while preserve fast startup. (AOT startup is about 2 times faster)

• Run some of the regular tests with profiling. Process and use the data in the time plots

• Assemblies loading

  • do not try to load AOT'ed assemblies when we know they are not in the apk (Release configuration)
  • Let Mono know where it can look for assemblies in general (e.g. skip the GAC, skip compile time host locations). We know exactly where the assemblies may be. This would limit calls to monodroid_dlopen and dlopen

• Measure performance regularly on devices as well - today we only use Android emulator to run the tests by the build bots. It might be also worth to run performance measurements on dedicated machine and collect data on mobile devices and emulators. That might be more stable compared to the build bots.

• Improve the way we use the typemap.{jm,mj} files. Currently they use the bsearch and strcmp to compare strings, thus recalculating string hashes continuously and the lookup function is called very often. It might be faster to enhance the typemap format with a precalculated hash of the string and then use an int -> typemap_entry dictionary/map to cut the number of hash calculations in half. With C++ we could use for instance sparsehash to make the comparisons faster than they are now.

Improvements in progress

• PR 2153 Generate JNI marshal methods
• PR 1886 Do not fallback in GetJavaToManagedType

Planned improvements

• Fix Bcl test measurements and add them to the plots again

• Generate and use JNI marshal methods for constructors used in the ConstructorBuilder to avoid last System.Reflection.Emit use

Finished improvements

• PR 2008 Faster native members registration
• PR 1890 Use the faster java type name mapping
• PR 1872 Avoid using Guid.NewGuid () for dynamic constructor names
• PR 1868 Avoid using Guid.NewGuid () for dynamic method names