Introduction and Motivation
Trimaran is a suite of tools
with a compiler frontend, IMPACT
a retargetable compiler backend, ELCOR and a retargetable simulator.
Recently a new addition, SMACHS (Smart Memory and Cache Hierarchy
Simulator) has been made to Trimaran. This framework allows one to
perform a number of experiments dealing with broad domains of computer
architecture, compilers etc. The compiler backend is able to perform
many machine dependent optimizations and is currently being used by HP
in its PICO-VLIW ASIP synthesis system.
Any C code is first parsed by the compiler frontend which
converts this into an intermediate format and performs classical
machine independent optimizations. This is used by ELCOR which uses
the machine description facility to perform machine dependent
optimizations as well as convert this to the ELCOR IR. The ELCOR is
taken by the simulator and converted to a low level C file. This file
is compiled on the host machine and linked with the emulation library.
Code size minimization is an important problem with VLIW
architectures. The effect of a particular encoding/decoding strategy
on application performance is an imporant criterion for choosing any
strategy. In an experimental framework like Trimaran it is possible
to explore the effect of a number of encoding/decoding strategies on
application performance as well as their memory characterstics. It is
also possible to explore the effect of decoder placement before or
after the cache.
Goals
The goal of this mini-project is to study the effect on application
performance of a particular encoding/decoding scheme. This can be
accomplished by modelling the particular decoding hardware as a
pipeline stage and capturing its effect as latency. To study the
effect of a particular caching strategy on the application
performance, the functionality needs to be put into the simulator. It
is possible to incorporate this in SMACHS.
Reports and Presentations
First version of presentation is available :
[ppt]
Draft version of report would be available shortly :
[ps]
Important Notes
- A lot of changes to the approach were made, these are detailed out in the presentation
as well as report! A completly automated version of the toolset would be available shortly.
- Please check out the
Embedded System Group website for details of our
other activities with Trimaran.
|