From 017361dd37b678efa44facc4a396784f4ce980bc Mon Sep 17 00:00:00 2001 From: Eric Anholt Date: Mon, 28 Oct 2013 00:11:45 -0700 Subject: [PATCH] i965: Compute the node's delay time for scheduling. This is a step in doing scheduling as described in Muchnick (p538). A difference is that our latency function is only specific to one instruction (it doesn't describe, for example, the different latency between WAR of a send's arguments and RAW of a send's destination), but that's changeable later. We also don't separately compute the postorder traversal of the graph, since we can use the setting of the delay field as the "visited" flag. Reviewed-by: Paul Berry --- .../dri/i965/brw_schedule_instructions.cpp | 28 +++++++++++++++++++ 1 file changed, 28 insertions(+) diff --git a/src/mesa/drivers/dri/i965/brw_schedule_instructions.cpp b/src/mesa/drivers/dri/i965/brw_schedule_instructions.cpp index 27de0e6991d..8437a4e02f4 100644 --- a/src/mesa/drivers/dri/i965/brw_schedule_instructions.cpp +++ b/src/mesa/drivers/dri/i965/brw_schedule_instructions.cpp @@ -89,6 +89,12 @@ public: int child_array_size; int unblocked_time; int latency; + + /** + * This is the sum of the instruction's latency plus the maximum delay of + * its children, or just the issue_time if it's a leaf node. + */ + int delay; }; void @@ -365,6 +371,7 @@ public: void run(exec_list *instructions); void add_inst(backend_instruction *inst); + void compute_delay(schedule_node *node); virtual void calculate_deps() = 0; virtual schedule_node *choose_instruction_to_schedule() = 0; @@ -439,6 +446,21 @@ instruction_scheduler::add_inst(backend_instruction *inst) instructions.push_tail(n); } +/** Recursive computation of the delay member of a node. */ +void +instruction_scheduler::compute_delay(schedule_node *n) +{ + if (!n->child_count) { + n->delay = issue_time(n->inst); + } else { + for (int i = 0; i < n->child_count; i++) { + if (!n->children[i]->delay) + compute_delay(n->children[i]); + n->delay = MAX2(n->delay, n->latency + n->children[i]->delay); + } + } +} + /** * Add a dependency between two instruction nodes. * @@ -1118,6 +1140,12 @@ instruction_scheduler::run(exec_list *all_instructions) break; } calculate_deps(); + + foreach_list(node, &instructions) { + schedule_node *n = (schedule_node *)node; + compute_delay(n); + } + schedule_instructions(next_block_header); } -- 2.30.2