Matt Turner <matts...@gmail.com> writes: > I think when this code was written, basic blocks were always ended by a > control flow instruction or an end-of-thread message. That's no longer > the case, and removing this restriction actually helps things: > > instructions in affected programs: 7267 -> 7244 (-0.32%) > helped: 4 > > total cycles in shared programs: 66559580 -> 66431900 (-0.19%) > cycles in affected programs: 28310152 -> 28182472 (-0.45%) > helped: 9577 > HURT: 879 > > GAINED: 2 > > The addition of the is_control_flow() checks is not a functional change, > since the add_insts_from_block() does not put them in the list of > instructions to schedule. I plan to change this in a later patch.
Reviewed-by: Francisco Jerez <curroje...@riseup.net>
> ---
> .../drivers/dri/i965/brw_schedule_instructions.cpp | 23
> +++-------------------
> 1 file changed, 3 insertions(+), 20 deletions(-)
>
> diff --git a/src/mesa/drivers/dri/i965/brw_schedule_instructions.cpp
> b/src/mesa/drivers/dri/i965/brw_schedule_instructions.cpp
> index 66eb07e..46b45a5 100644
> --- a/src/mesa/drivers/dri/i965/brw_schedule_instructions.cpp
> +++ b/src/mesa/drivers/dri/i965/brw_schedule_instructions.cpp
> @@ -923,15 +923,6 @@ fs_instruction_scheduler::calculate_deps()
> */
> schedule_node *last_fixed_grf_write = NULL;
>
> - /* The last instruction always needs to still be the last
> - * instruction. Either it's flow control (IF, ELSE, ENDIF, DO,
> - * WHILE) and scheduling other things after it would disturb the
> - * basic block, or it's FB_WRITE and we should do a better job at
> - * dead code elimination anyway.
> - */
> - schedule_node *last = (schedule_node *)instructions.get_tail();
> - add_barrier_deps(last);
> -
> memset(last_grf_write, 0, sizeof(last_grf_write));
> memset(last_mrf_write, 0, sizeof(last_mrf_write));
>
> @@ -940,7 +931,8 @@ fs_instruction_scheduler::calculate_deps()
> fs_inst *inst = (fs_inst *)n->inst;
>
> if (inst->opcode == FS_OPCODE_PLACEHOLDER_HALT ||
> - inst->has_side_effects())
> + inst->is_control_flow() ||
> + inst->has_side_effects())
> add_barrier_deps(n);
>
> /* read-after-write deps. */
> @@ -1166,15 +1158,6 @@ vec4_instruction_scheduler::calculate_deps()
> */
> schedule_node *last_fixed_grf_write = NULL;
>
> - /* The last instruction always needs to still be the last instruction.
> - * Either it's flow control (IF, ELSE, ENDIF, DO, WHILE) and scheduling
> - * other things after it would disturb the basic block, or it's the EOT
> - * URB_WRITE and we should do a better job at dead code eliminating
> - * anything that could have been scheduled after it.
> - */
> - schedule_node *last = (schedule_node *)instructions.get_tail();
> - add_barrier_deps(last);
> -
> memset(last_grf_write, 0, sizeof(last_grf_write));
> memset(last_mrf_write, 0, sizeof(last_mrf_write));
>
> @@ -1182,7 +1165,7 @@ vec4_instruction_scheduler::calculate_deps()
> foreach_in_list(schedule_node, n, &instructions) {
> vec4_instruction *inst = (vec4_instruction *)n->inst;
>
> - if (inst->has_side_effects())
> + if (inst->is_control_flow() || inst->has_side_effects())
> add_barrier_deps(n);
>
> /* read-after-write deps. */
> --
> 2.4.10
>
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> mesa-dev@lists.freedesktop.org
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