[Mesa-dev] [PATCH 06/11] st/mesa: add atomic buffer support

[Kai Wasserbäch]

Ilia Mirkin wrote on 27.09.2015 08:33:
> Signed-off-by: Ilia Mirkin <imirkin at alum.mit.edu>
> ---
>  src/mesa/Makefile.sources                    |   1 +
>  src/mesa/program/ir_to_mesa.cpp              |   4 +-
>  src/mesa/state_tracker/st_atom.c             |   5 +
>  src/mesa/state_tracker/st_atom.h             |   5 +
>  src/mesa/state_tracker/st_atom_atomicbuf.c   | 151 +++++++++++++++++++++++++++
>  src/mesa/state_tracker/st_cb_bufferobjects.c |   3 +
>  src/mesa/state_tracker/st_context.c          |   1 +
>  src/mesa/state_tracker/st_context.h          |   1 +
>  src/mesa/state_tracker/st_extensions.c       |  15 +++
>  src/mesa/state_tracker/st_glsl_to_tgsi.cpp   | 133 +++++++++++++++++++++--
>  10 files changed, 310 insertions(+), 9 deletions(-)
>  create mode 100644 src/mesa/state_tracker/st_atom_atomicbuf.c
> 
> [...]
> diff --git a/src/mesa/state_tracker/st_glsl_to_tgsi.cpp b/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
> index 633e90f..28c9637 100644
> --- a/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
> +++ b/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
> @@ -261,6 +261,8 @@ public:
> [...]
>  
>  void
> +glsl_to_tgsi_visitor::visit_atomic_counter_intrinsic(ir_call *ir)
> +{
> +   const char *callee = ir->callee->function_name();
> +   ir_dereference *deref = static_cast<ir_dereference *>(
> +      ir->actual_parameters.get_head());
> +   ir_variable *location = deref->variable_referenced();
> +
> +   /* XXX use accept */
> +   st_src_reg buffer(
> +         PROGRAM_SAMPLER, location->data.binding /* XXX */, GLSL_TYPE_ATOMIC_UINT);
> +
> +   /* Calculate the surface offset */
> +   st_src_reg offset;
> +   ir_dereference_array *deref_array = deref->as_dereference_array();
> +
> +   if (deref_array) {
> +      offset = get_temp(glsl_type::uint_type);
> +
> +      deref_array->array_index->accept(this);
> +
> +      emit_asm(ir, TGSI_OPCODE_MUL, st_dst_reg(offset),
> +               this->result, st_src_reg_for_int(ATOMIC_COUNTER_SIZE));
> +      emit_asm(ir, TGSI_OPCODE_ADD, st_dst_reg(offset),
> +               offset, st_src_reg_for_int(location->data.atomic.offset));
> +   } else {
> +      offset = st_src_reg_for_int(location->data.atomic.offset);
> +   }
> +
> +   ir->return_deref->accept(this);
> +   st_dst_reg dst(this->result);
> +   dst.writemask = WRITEMASK_X;
> +
> +   glsl_to_tgsi_instruction *inst;
> +
> +   if (!strcmp("__intrinsic_atomic_read", callee)) {
> +      inst = emit_asm(ir, TGSI_OPCODE_LOAD, dst, offset);
> +      inst->buffer = buffer;
> +   } else if (!strcmp("__intrinsic_atomic_increment", callee)) {
> +      inst = emit_asm(ir, TGSI_OPCODE_ATOMUADD, dst, offset,
> +                      st_src_reg_for_int(1));
> +      inst->buffer = buffer;
> +   } else if (!strcmp("__intrinsic_atomic_predecrement", callee)) {
> +      inst = emit_asm(ir, TGSI_OPCODE_ATOMUADD, dst, offset,
> +                      st_src_reg_for_int(-1));
> +      inst->buffer = buffer;
> +      emit_asm(ir, TGSI_OPCODE_ADD, dst, this->result, st_src_reg_for_int(-1));
> +   }
> +}
> +
> +void
>  glsl_to_tgsi_visitor::visit(ir_call *ir)
>  {
>     glsl_to_tgsi_instruction *call_inst;
>     ir_function_signature *sig = ir->callee;
> +   const char *callee = sig->function_name();
>     function_entry *entry = get_function_signature(sig);
>     int i;
>  
> +   /* Filter out intrinsics */
> +   if (!strcmp("__intrinsic_atomic_read", callee) ||
> +       !strcmp("__intrinsic_atomic_increment", callee) ||
> +       !strcmp("__intrinsic_atomic_predecrement", callee)) {
> +      visit_atomic_counter_intrinsic(ir);
> +      return;
> +   }

You're doing the same string comparison two times in a row (if you match here).
Wouldn't it be cheaper to cache the result und pass it in to
visit_atomic_counter_intrinsic()?

I was thinking of something like

unsigned atomic_intr_type = 0;
if(!strcmp("__intrinsic_atomic_read", callee))
  atomic_intr_type = 1;
else if(!strcmp("__intrinsic_atomic_increment", callee))
  atomic_intr_type = 2;
else if(!strcmp("__intrinsic_atomic_predecrement", callee))
  atomic_intr_type = 3;

if(atomic_intr_type) {
  visit_atomic_counter_intrinsic(ir, atomic_intr_type);
  return;
}

Obviously visit_atomic_counter_intrinsic() would need to take that parameter and
then replace the respective if block with a check for the right code.


This is just a suggestion and I might be totally missing something here. ;-)

Cheers,
Kai

-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 630 bytes
Desc: OpenPGP digital signature
URL: <http://lists.freedesktop.org/archives/mesa-dev/attachments/20150927/02064db4/attachment.sig>