[LAD] Project proposition: llvm based dsp engine
Maurizio De Cecco
jmax at dececco.name
Mon Dec 6 11:10:02 UTC 2010
I have been looking for a while to LLVM as a possible technology to
build a DSP execution engine, providing the runtime flexibility needed
by real-time interactive DSP applications (like patcher languages), or
by plug-in based processors, and in the same moment
the powerful link time optimizations that such a system can provide.
Such a task is daunting for a single developer project like mine, but it
may become feasible if such engine could be useful for multiple
projects, so to become a community initiative (i am sending this
mail to the Linux Audio Developers mailing list and to the LLVM mailing
list, feel free to send it elsewhere if you find it useful).
So, I'll explain in a few lines exactly what i thinking of, and i
propose that if anybody is interested in such initiative she/he can
contact me directly, and we will see if there is enough interest
for actually start something. Of course, i may also miss an existing
project on the same field, in this case, let me know :->.
The idea is the following: build a tool kit, based on LLVM, to
dynamically build the execution chain of DSP applications; almost all
DSP applications using plug-ins have something of this kind.
This toolkit will be based on code generation and JIT, and should have a
flexible architecture so to accomodate multiple plugin API/ABI, to be
able to call, from the same execution chain, DSP operation written
for different contexts (for example, LADSPA plug-ins, PD objects, and so
on). The code generation would allow this integration for a very low run
But the most interesting part is actually providing a definition of
native, LLVM compiled, plug-ins, and to use the LLVM link time
optimizations for doing things like inlining, loop fusions etc, between
different DSP operation; this can provide quite a speed improvement for
those chains composed of simple operators.
The execution chain should be flexible enough to provide support for
multi-rate synchronous data flows, and should include support for
multiple threads execution (probably different chains for different
To complete the project, let's add a library of DSP operators, a
reasonable high level API to use it, and documentation to help the DSP
application designer (i find the LLVM learning curve quite steep :).
Contact maurizio at dececco.name if you are interest in setting up such a
project; if enough developers with the right skills and enough interest
are found I'll set up a project mailing list to further discuss the subject.
Maurizio De Cecco -
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