[Mono-list] Re: The Mauve unicode testcase and VM performance
Miguel de Icaza
Wed, 14 Apr 2004 11:50:49 -0400
> > Interestingly, my installation of mono (from debian sid) doesn't even
> > come with its own libraries AOT'd. I'd have thought that you'd get the
> > best performance by AOT'ing *all* the libraries, including (and
> > especially) the low-level platform ones such as System.dll and
> > System.Xml.dll.
> AOT (or pre-JITing) assemblies is not as useful as you'd think. It has
> two primary effects:
> - Reduce memory requirements, as memory doesn't need to be allocated
> for the JITed code
> - Decrease startup time, as (again) the JITing doesn't need to be
Another effect is that you can run the most time consuming
optimizations on those assemblies. For example, using AOT with -O=all
on mcs.exe gives about 15% performance increase:
mono --aot -O=all /usr/bin/mcs.exe
If you also apply this to mscorlib and System, you get another 7-12%.
Useful when you are doing a lot of compilations.