[Mesa-dev] r600g shader optimization

[Christian König]

Hi Vadim,

wow quite impressive, does it also contains peep-hole optimisation?

I tried to implement that once, but failed because I never got all the
dependencies between opcodes correctly resolved. Rescheduling export
instructions and setting the barrier flag of CF instructions correctly
can also be quite an improvement.

Just a side note in commit "r600g: make some functions in r600_asm.c
externally accessible" you make a whole bunch of functions externally
accessible, but didn't add a proper prefix like "r600_" to the function
name. That could led to a bit confusion when somebody else tries to hack
on the code.

Regards,
Christian.


Am Freitag, den 07.10.2011, 18:14 +0400 schrieb Vadim Girlin:
> Hi,
> 
> Recently I've been working on the shader optimization for r600g, and now
> I have the initial working implementation of simple alu scheduler and
> register allocator. It has no piglit regressions, though it's still a
> work in progress and there are known issues with some applications.
> 
> I've pushed the working branch to github:
> https://github.com/VadimGirlin/mesa/tree/r600_shader_opt
> 
> Currently it supports evergreen only, but I'm planning to make it work
> with other chips too. It uses "struct r600_bytecode" as the source,
> converting it to SSA-based internal representation. I'm going to
> implement some optimization passes at that phase, but currently it's
> then doing final steps - register allocation, alu scheduling, and
> building new bytecode.
> 
> I'm attaching as an example the dump for one of the shaders in the
> glxgears. You could get such dump for all shaders before and after
> processing by setting R600_OPT_DUMP environment variable to 2. Setting
> this variable to 1 will only print some information for the processed
> shaders - size, number of gprs, and number of alu instruction groups.
> 
> Vadim
> 
> 
> 
> 
> 
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