[squeak-dev] new Cog VMs

Francisco Ortiz Peñaloza patchinko at gmail.com
Fri Dec 31 03:27:14 UTC 2010


Thanks Eliot!
Francisco

On Fri, Dec 31, 2010 at 12:37 AM, Germán Arduino <garduino at gmail.com> wrote:

> Wow fantastic!
> I will try tomorrow on my usual development work.
> Thanks by share!
> German.
>
> 2010/12/30, Eliot Miranda <eliot.miranda at gmail.com>:
> > Hi All,
> >
> >      I've released a new version of Cog that has a substantially improved
> > code generator along the lines of Peter Deutsch's HPS (VisualWorks) and
> > various of Ian Piumarta's VMs.  These all use a simple tecnique to
> identify
> > constant references in bytecode and to support a register-based calling
> > convention.  While this does produce faster code it tends to accelerate
> > low-level code much more than high-level code as you can see by the
> > following benchmarks:
> >
> > SimpleStackBasedCogit: [1 to: 100000000 do: [:i|]] timeToRun 691
> > StackToRegisterMappingCogit: [1 to: 100000000 do: [:i|]] timeToRun 192
> > 192 - 691 / 6.91 -72%
> >
> > SimpleStackBasedCogit: 0 tinyBenchmarks '753495217 bytecodes/sec;
> 64769127
> > sends/sec'
> > StackToRegisterMappingCogit: 0 tinyBenchmarks '931756141 bytecodes/sec;
> > 128157989 sends/sec'
> > 931756141 - 753495217 / 7534952.17 -24%
> > 128157989 - 64769127 / 647691.27 -98%
> >
> > SimpleStackBasedCogit: [Compiler recompileAll] timeToRun 47013 (no
> > transcript
> > StackToRegisterMappingCogit: [Compiler recompileAll] timeToRun 43406 (no
> > transcript)
> > 43406 - 47013 / 470.13 -7.67234594686576
> >
> > The status of this code is essentially beta.  The test suite runs the
> same
> > on the new code generator as on the old, but I think there are still bugs
> > because I get the occasional transient error.  I am therefore very
> > interested in any reproducible errors you can find.
> >
> > The VMs (http://www.mirandabanda.org/files/Cog/VM/VM.r2334/) contain a
> few
> > other important changes:
> >
> > - a bug fix to bytecode<->native pc mappng that produced incorrect
> results
> > for methods containing blocks with ^-returns in them.  One symptom is
> > incorrect highlighting of the pc in the debugger, althoguh symptoms could
> be
> > much serious.
> >
> > - jitting interpreted methods on backward branches.  Currently any
> > interpreted method that performs more than 20 backward branches will be
> > considered for JIT compilation and if it is suitable (default, <= 60
> > literals) will be compiled to native code.
> >
> > - new callback support.  I need to commit some changes to the Alien
> package
> > to provide access to this but essentially the VM's callback support is
> now
> > able to be ported to architectures with register-based calling
> conventions
> > (ARM, PowerPC, SPARC etc).  I'll try and get the Alien code released
> soon,
> > and to back-port the changes to the standard VM before the end of the
> > holiday.
> >
> > One thing that is still /not/ fixed is the lack of a SoundPlugin on
> win32.
> >  Apologies.  I'll try and get a fix for this before the end of the
> holidays
> > too, but time might be too tight.  There are other priorities such as
> > harmonising the standard and Cog VMs for the 4.2 release.
> >
> > best
> > Eliot
> >
>
>
> --
> =================================================
> Germán S. Arduino  <gsa @ arsol.net>   Twitter: garduino
> Arduino Software & Web Hosting   http://www.arduinosoftware.com
> PasswordsPro  http://www.passwordspro.com
> =================================================
>
>
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