[Mesa-dev] [PATCH 06/10] i965: Reduce maximum GL_ARB_fragment_program instruction count to 1024.

[Ian Romanick]

On 09/24/2012 12:06 PM, Kenneth Graunke wrote:
> On 09/22/2012 02:04 PM, Eric Anholt wrote:
>> I don't know of any programs that would need more than this.  The larger
>> programs I've seen have neared 100 instructions.  This prevent excessive
>> runtimes of automatic tests that attempt to test up to the exposed maximums
>> (like fp-long-alu).
>> ---
>>   src/mesa/drivers/dri/i965/brw_context.c |    8 ++++----
>>   1 file changed, 4 insertions(+), 4 deletions(-)
>>
>> diff --git a/src/mesa/drivers/dri/i965/brw_context.c b/src/mesa/drivers/dri/i965/brw_context.c
>> index 1083e28..a7d61bd 100644
>> --- a/src/mesa/drivers/dri/i965/brw_context.c
>> +++ b/src/mesa/drivers/dri/i965/brw_context.c
>> @@ -250,10 +250,10 @@ brwCreateContext(int api,
>>         MIN2(ctx->Const.VertexProgram.MaxNativeParameters,
>>   	   ctx->Const.VertexProgram.MaxEnvParams);
>>
>> -   ctx->Const.FragmentProgram.MaxNativeInstructions = (16 * 1024);
>> -   ctx->Const.FragmentProgram.MaxNativeAluInstructions = (16 * 1024);
>> -   ctx->Const.FragmentProgram.MaxNativeTexInstructions = (16 * 1024);
>> -   ctx->Const.FragmentProgram.MaxNativeTexIndirections = (16 * 1024);
>> +   ctx->Const.FragmentProgram.MaxNativeInstructions = (1 * 1024);
>> +   ctx->Const.FragmentProgram.MaxNativeAluInstructions = (1 * 1024);
>> +   ctx->Const.FragmentProgram.MaxNativeTexInstructions = (1 * 1024);
>> +   ctx->Const.FragmentProgram.MaxNativeTexIndirections = (1 * 1024);
>>      ctx->Const.FragmentProgram.MaxNativeAttribs = 12;
>>      ctx->Const.FragmentProgram.MaxNativeTemps = 256;
>>      ctx->Const.FragmentProgram.MaxNativeAddressRegs = 0;
>
> I've definitely seen 600 instruction shaders generated by Cg.  (Some
> Crystal Space based games use shaders written in Cg, which translates to
> stellar ARBfp code...)  I'm afraid there may be even bigger ones.

Maybe make it a driconf option?  That way if someone has an app that 
needs more, they can set it.  *shrug*