Mesa (master): vc4: Switch the post-RA scheduler over to the DAG datastructure.
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Mon Mar 11 20:15:47 UTC 2019
Module: Mesa
Branch: master
Commit: 3a9e2d608563d6d305c63039396644f3b976a55d
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=3a9e2d608563d6d305c63039396644f3b976a55d
Author: Eric Anholt <eric at anholt.net>
Date: Thu Feb 28 12:02:58 2019 -0800
vc4: Switch the post-RA scheduler over to the DAG datastructure.
Just a small code reduction from shared infrastructure.
---
src/gallium/drivers/vc4/vc4_qpu_schedule.c | 183 ++++++++++++-----------------
1 file changed, 73 insertions(+), 110 deletions(-)
diff --git a/src/gallium/drivers/vc4/vc4_qpu_schedule.c b/src/gallium/drivers/vc4/vc4_qpu_schedule.c
index 7bd3e179539..c150e951664 100644
--- a/src/gallium/drivers/vc4/vc4_qpu_schedule.c
+++ b/src/gallium/drivers/vc4/vc4_qpu_schedule.c
@@ -37,18 +37,16 @@
#include "vc4_qir.h"
#include "vc4_qpu.h"
#include "util/ralloc.h"
+#include "util/dag.h"
static bool debug;
struct schedule_node_child;
struct schedule_node {
+ struct dag_node dag;
struct list_head link;
struct queued_qpu_inst *inst;
- struct schedule_node_child *children;
- uint32_t child_count;
- uint32_t child_array_size;
- uint32_t parent_count;
/* Longest cycles + instruction_latency() of any parent of this node. */
uint32_t unblocked_time;
@@ -73,17 +71,13 @@ struct schedule_node {
int uniform;
};
-struct schedule_node_child {
- struct schedule_node *node;
- bool write_after_read;
-};
-
/* When walking the instructions in reverse, we need to swap before/after in
* add_dep().
*/
enum direction { F, R };
struct schedule_state {
+ struct dag *dag;
struct schedule_node *last_r[6];
struct schedule_node *last_ra[32];
struct schedule_node *last_rb[32];
@@ -105,37 +99,17 @@ add_dep(struct schedule_state *state,
bool write)
{
bool write_after_read = !write && state->dir == R;
+ void *edge_data = (void *)(uintptr_t)write_after_read;
if (!before || !after)
return;
assert(before != after);
- if (state->dir == R) {
- struct schedule_node *t = before;
- before = after;
- after = t;
- }
-
- for (int i = 0; i < before->child_count; i++) {
- if (before->children[i].node == after &&
- (before->children[i].write_after_read == write_after_read)) {
- return;
- }
- }
-
- if (before->child_array_size <= before->child_count) {
- before->child_array_size = MAX2(before->child_array_size * 2, 16);
- before->children = reralloc(before, before->children,
- struct schedule_node_child,
- before->child_array_size);
- }
-
- before->children[before->child_count].node = after;
- before->children[before->child_count].write_after_read =
- write_after_read;
- before->child_count++;
- after->parent_count++;
+ if (state->dir == F)
+ dag_add_edge(&before->dag, &after->dag, edge_data);
+ else
+ dag_add_edge(&after->dag, &before->dag, edge_data);
}
static void
@@ -438,11 +412,13 @@ calculate_deps(struct schedule_state *state, struct schedule_node *n)
}
static void
-calculate_forward_deps(struct vc4_compile *c, struct list_head *schedule_list)
+calculate_forward_deps(struct vc4_compile *c, struct dag *dag,
+ struct list_head *schedule_list)
{
struct schedule_state state;
memset(&state, 0, sizeof(state));
+ state.dag = dag;
state.dir = F;
list_for_each_entry(struct schedule_node, node, schedule_list, link)
@@ -450,11 +426,13 @@ calculate_forward_deps(struct vc4_compile *c, struct list_head *schedule_list)
}
static void
-calculate_reverse_deps(struct vc4_compile *c, struct list_head *schedule_list)
+calculate_reverse_deps(struct vc4_compile *c, struct dag *dag,
+ struct list_head *schedule_list)
{
struct schedule_state state;
memset(&state, 0, sizeof(state));
+ state.dag = dag;
state.dir = R;
list_for_each_entry_rev(struct schedule_node, node, schedule_list,
@@ -464,6 +442,7 @@ calculate_reverse_deps(struct vc4_compile *c, struct list_head *schedule_list)
}
struct choose_scoreboard {
+ struct dag *dag;
int tick;
int last_sfu_write_tick;
int last_uniforms_reset_tick;
@@ -587,7 +566,8 @@ choose_instruction_to_schedule(struct choose_scoreboard *scoreboard,
}
}
- list_for_each_entry(struct schedule_node, n, schedule_list, link) {
+ list_for_each_entry(struct schedule_node, n, &scoreboard->dag->heads,
+ dag.link) {
uint64_t inst = n->inst->inst;
uint32_t sig = QPU_GET_FIELD(inst, QPU_SIG);
@@ -597,7 +577,7 @@ choose_instruction_to_schedule(struct choose_scoreboard *scoreboard,
* slots.
*/
if (sig == QPU_SIG_BRANCH &&
- !list_is_singular(schedule_list)) {
+ !list_is_singular(&scoreboard->dag->heads)) {
continue;
}
@@ -703,23 +683,24 @@ update_scoreboard_for_chosen(struct choose_scoreboard *scoreboard,
}
static void
-dump_state(struct list_head *schedule_list)
+dump_state(struct dag *dag)
{
- list_for_each_entry(struct schedule_node, n, schedule_list, link) {
+ list_for_each_entry(struct schedule_node, n, &dag->heads, dag.link) {
fprintf(stderr, " t=%4d: ", n->unblocked_time);
vc4_qpu_disasm(&n->inst->inst, 1);
fprintf(stderr, "\n");
- for (int i = 0; i < n->child_count; i++) {
- struct schedule_node *child = n->children[i].node;
+ util_dynarray_foreach(&n->dag.edges, struct dag_edge, edge) {
+ struct schedule_node *child =
+ (struct schedule_node *)edge->child;
if (!child)
continue;
fprintf(stderr, " - ");
vc4_qpu_disasm(&child->inst->inst, 1);
fprintf(stderr, " (%d parents, %c)\n",
- child->parent_count,
- n->children[i].write_after_read ? 'w' : 'r');
+ child->dag.parent_count,
+ edge->data ? 'w' : 'r');
}
}
}
@@ -786,59 +767,55 @@ instruction_latency(struct schedule_node *before, struct schedule_node *after)
/** Recursive computation of the delay member of a node. */
static void
-compute_delay(struct schedule_node *n)
+compute_delay(struct dag_node *node, void *state)
{
- if (!n->child_count) {
- n->delay = 1;
- } else {
- for (int i = 0; i < n->child_count; i++) {
- if (!n->children[i].node->delay)
- compute_delay(n->children[i].node);
- n->delay = MAX2(n->delay,
- n->children[i].node->delay +
- instruction_latency(n, n->children[i].node));
- }
+ struct schedule_node *n = (struct schedule_node *)node;
+
+ n->delay = 1;
+
+ util_dynarray_foreach(&n->dag.edges, struct dag_edge, edge) {
+ struct schedule_node *child =
+ (struct schedule_node *)edge->child;
+ n->delay = MAX2(n->delay, (child->delay +
+ instruction_latency(n, child)));
}
}
+/* Removes a DAG head, but removing only the WAR edges. (dag_prune_head()
+ * should be called on it later to finish pruning the other edges).
+ */
static void
-mark_instruction_scheduled(struct list_head *schedule_list,
+pre_remove_head(struct dag *dag, struct schedule_node *n)
+{
+ list_delinit(&n->dag.link);
+
+ util_dynarray_foreach(&n->dag.edges, struct dag_edge, edge) {
+ if (edge->data)
+ dag_remove_edge(dag, edge);
+ }
+}
+
+static void
+mark_instruction_scheduled(struct dag *dag,
uint32_t time,
- struct schedule_node *node,
- bool war_only)
+ struct schedule_node *node)
{
if (!node)
return;
- for (int i = node->child_count - 1; i >= 0; i--) {
+ util_dynarray_foreach(&node->dag.edges, struct dag_edge, edge) {
struct schedule_node *child =
- node->children[i].node;
+ (struct schedule_node *)edge->child;
if (!child)
continue;
- if (war_only && !node->children[i].write_after_read)
- continue;
-
- /* If the requirement is only that the node not appear before
- * the last read of its destination, then it can be scheduled
- * immediately after (or paired with!) the thing reading the
- * destination.
- */
- uint32_t latency = 0;
- if (!war_only) {
- latency = instruction_latency(node,
- node->children[i].node);
- }
+ uint32_t latency = instruction_latency(node, child);
child->unblocked_time = MAX2(child->unblocked_time,
time + latency);
- child->parent_count--;
- if (child->parent_count == 0)
- list_add(&child->link, schedule_list);
-
- node->children[i].node = NULL;
}
+ dag_prune_head(dag, &node->dag);
}
/**
@@ -897,19 +874,7 @@ schedule_instructions(struct vc4_compile *c,
{
uint32_t time = 0;
- if (debug) {
- fprintf(stderr, "initial deps:\n");
- dump_state(schedule_list);
- fprintf(stderr, "\n");
- }
-
- /* Remove non-DAG heads from the list. */
- list_for_each_entry_safe(struct schedule_node, n, schedule_list, link) {
- if (n->parent_count != 0)
- list_del(&n->link);
- }
-
- while (!list_empty(schedule_list)) {
+ while (!list_empty(&scoreboard->dag->heads)) {
struct schedule_node *chosen =
choose_instruction_to_schedule(scoreboard,
schedule_list,
@@ -924,7 +889,7 @@ schedule_instructions(struct vc4_compile *c,
if (debug) {
fprintf(stderr, "t=%4d: current list:\n",
time);
- dump_state(schedule_list);
+ dump_state(scoreboard->dag);
fprintf(stderr, "t=%4d: chose: ", time);
vc4_qpu_disasm(&inst, 1);
fprintf(stderr, "\n");
@@ -935,9 +900,7 @@ schedule_instructions(struct vc4_compile *c,
*/
if (chosen) {
time = MAX2(chosen->unblocked_time, time);
- list_del(&chosen->link);
- mark_instruction_scheduled(schedule_list, time,
- chosen, true);
+ pre_remove_head(scoreboard->dag, chosen);
if (chosen->uniform != -1) {
c->uniform_data[*next_uniform] =
orig_uniform_data[chosen->uniform];
@@ -951,7 +914,6 @@ schedule_instructions(struct vc4_compile *c,
chosen);
if (merge) {
time = MAX2(merge->unblocked_time, time);
- list_del(&merge->link);
inst = qpu_merge_inst(inst, merge->inst->inst);
assert(inst != 0);
if (merge->uniform != -1) {
@@ -983,8 +945,8 @@ schedule_instructions(struct vc4_compile *c,
* be scheduled. Update the children's unblocked time for this
* DAG edge as we do so.
*/
- mark_instruction_scheduled(schedule_list, time, chosen, false);
- mark_instruction_scheduled(schedule_list, time, merge, false);
+ mark_instruction_scheduled(scoreboard->dag, time, chosen);
+ mark_instruction_scheduled(scoreboard->dag, time, merge);
if (QPU_GET_FIELD(inst, QPU_SIG) == QPU_SIG_THREAD_SWITCH ||
QPU_GET_FIELD(inst, QPU_SIG) == QPU_SIG_LAST_THREAD_SWITCH) {
@@ -1026,18 +988,20 @@ qpu_schedule_instructions_block(struct vc4_compile *c,
uint32_t *orig_uniform_data,
uint32_t *next_uniform)
{
- void *mem_ctx = ralloc_context(NULL);
- struct list_head schedule_list;
+ scoreboard->dag = dag_create(NULL);
+ struct list_head setup_list;
- list_inithead(&schedule_list);
+ list_inithead(&setup_list);
/* Wrap each instruction in a scheduler structure. */
uint32_t next_sched_uniform = *next_uniform;
while (!list_empty(&block->qpu_inst_list)) {
struct queued_qpu_inst *inst =
(struct queued_qpu_inst *)block->qpu_inst_list.next;
- struct schedule_node *n = rzalloc(mem_ctx, struct schedule_node);
+ struct schedule_node *n = rzalloc(scoreboard->dag,
+ struct schedule_node);
+ dag_init_node(scoreboard->dag, &n->dag);
n->inst = inst;
if (reads_uniform(inst->inst)) {
@@ -1046,23 +1010,22 @@ qpu_schedule_instructions_block(struct vc4_compile *c,
n->uniform = -1;
}
list_del(&inst->link);
- list_addtail(&n->link, &schedule_list);
+ list_addtail(&n->link, &setup_list);
}
- calculate_forward_deps(c, &schedule_list);
- calculate_reverse_deps(c, &schedule_list);
+ calculate_forward_deps(c, scoreboard->dag, &setup_list);
+ calculate_reverse_deps(c, scoreboard->dag, &setup_list);
- list_for_each_entry(struct schedule_node, n, &schedule_list, link) {
- compute_delay(n);
- }
+ dag_traverse_bottom_up(scoreboard->dag, compute_delay, NULL);
uint32_t cycles = schedule_instructions(c, scoreboard, block,
- &schedule_list,
+ &setup_list,
orig_uniform_contents,
orig_uniform_data,
next_uniform);
- ralloc_free(mem_ctx);
+ ralloc_free(scoreboard->dag);
+ scoreboard->dag = NULL;
return cycles;
}
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