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authorJose Maria Casanova Crespo <jmcasanova@igalia.com>2019-07-02 16:31:09 (GMT)
committerJose Maria Casanova Crespo <jmcasanova@igalia.com>2019-07-22 01:00:50 (GMT)
commitc341ab7ffbac822d3d3cbb3d3ae9d2a19ea3cc9a (patch)
tree70eba195aec80c8ba4d6f0f721fd957b386e933f
parentf7224014df0d366453739356b9968ca94ad43979 (diff)
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v3d: add shader-db stat to count SFU stalls
SFU operations have a latency of 2 cicles, so if their results are used in the following cycle to a SFU instruction, the GPU stalls for an extra cycle until the result is available. This adds the number of stalls to the shader-db debug mode and sum of instruction + stalls to evaluate optimizations to schedule instructions that avoid generating sfu-stalls. v2: Rename v3d_qpu_generates_sfu_stalls to v3d_qpu_instr_is_sfu (Eric) Reviewed-by: Eric Anholt <eric@anholt.net>
-rw-r--r--src/broadcom/compiler/qpu_schedule.c45
-rw-r--r--src/broadcom/compiler/v3d_compiler.h1
-rw-r--r--src/broadcom/compiler/vir.c7
-rw-r--r--src/broadcom/qpu/qpu_instr.c34
-rw-r--r--src/broadcom/qpu/qpu_instr.h1
5 files changed, 74 insertions, 14 deletions
diff --git a/src/broadcom/compiler/qpu_schedule.c b/src/broadcom/compiler/qpu_schedule.c
index b8e04f6..370881b 100644
--- a/src/broadcom/compiler/qpu_schedule.c
+++ b/src/broadcom/compiler/qpu_schedule.c
@@ -440,6 +440,8 @@ struct choose_scoreboard {
struct dag *dag;
int tick;
int last_magic_sfu_write_tick;
+ int last_stallable_sfu_reg;
+ int last_stallable_sfu_tick;
int last_ldvary_tick;
int last_uniforms_reset_tick;
int last_thrsw_tick;
@@ -531,6 +533,33 @@ pixel_scoreboard_too_soon(struct choose_scoreboard *scoreboard,
return (scoreboard->tick == 0 && qpu_inst_is_tlb(inst));
}
+static bool
+qpu_instruction_uses_rf(const struct v3d_qpu_instr *inst,
+ uint32_t waddr) {
+
+ if (inst->type != V3D_QPU_INSTR_TYPE_ALU)
+ return false;
+
+ if (v3d_qpu_uses_mux(inst, V3D_QPU_MUX_A) &&
+ inst->raddr_a == waddr)
+ return true;
+
+ if (v3d_qpu_uses_mux(inst, V3D_QPU_MUX_B) &&
+ !inst->sig.small_imm && (inst->raddr_b == waddr))
+ return true;
+
+ return false;
+}
+
+static bool
+mux_read_stalls(struct choose_scoreboard *scoreboard,
+ const struct v3d_qpu_instr *inst)
+{
+ return scoreboard->tick == scoreboard->last_stallable_sfu_tick + 1 &&
+ qpu_instruction_uses_rf(inst,
+ scoreboard->last_stallable_sfu_reg);
+}
+
static int
get_instruction_priority(const struct v3d_qpu_instr *inst)
{
@@ -852,6 +881,16 @@ update_scoreboard_for_magic_waddr(struct choose_scoreboard *scoreboard,
}
static void
+update_scoreboard_for_sfu_stall_waddr(struct choose_scoreboard *scoreboard,
+ const struct v3d_qpu_instr *inst)
+{
+ if (v3d_qpu_instr_is_sfu(inst)) {
+ scoreboard->last_stallable_sfu_reg = inst->alu.add.waddr;
+ scoreboard->last_stallable_sfu_tick = scoreboard->tick;
+ }
+}
+
+static void
update_scoreboard_for_chosen(struct choose_scoreboard *scoreboard,
const struct v3d_qpu_instr *inst)
{
@@ -864,6 +903,9 @@ update_scoreboard_for_chosen(struct choose_scoreboard *scoreboard,
if (inst->alu.add.magic_write) {
update_scoreboard_for_magic_waddr(scoreboard,
inst->alu.add.waddr);
+ } else {
+ update_scoreboard_for_sfu_stall_waddr(scoreboard,
+ inst);
}
}
@@ -1298,6 +1340,8 @@ schedule_instructions(struct v3d_compile *c,
fprintf(stderr, "\n");
}
}
+ if (mux_read_stalls(scoreboard, inst))
+ c->qpu_inst_stalled_count++;
}
/* Update the uniform index for the rewritten location --
@@ -1481,6 +1525,7 @@ v3d_qpu_schedule_instructions(struct v3d_compile *c)
scoreboard.last_magic_sfu_write_tick = -10;
scoreboard.last_uniforms_reset_tick = -10;
scoreboard.last_thrsw_tick = -10;
+ scoreboard.last_stallable_sfu_tick = -10;
if (debug) {
fprintf(stderr, "Pre-schedule instructions\n");
diff --git a/src/broadcom/compiler/v3d_compiler.h b/src/broadcom/compiler/v3d_compiler.h
index da32d47..b61119f 100644
--- a/src/broadcom/compiler/v3d_compiler.h
+++ b/src/broadcom/compiler/v3d_compiler.h
@@ -613,6 +613,7 @@ struct v3d_compile {
uint64_t *qpu_insts;
uint32_t qpu_inst_count;
uint32_t qpu_inst_size;
+ uint32_t qpu_inst_stalled_count;
/* For the FS, the number of varying inputs not counting the
* point/line varyings payload
diff --git a/src/broadcom/compiler/vir.c b/src/broadcom/compiler/vir.c
index 04129fa..eed3fc1 100644
--- a/src/broadcom/compiler/vir.c
+++ b/src/broadcom/compiler/vir.c
@@ -947,7 +947,8 @@ uint64_t *v3d_compile(const struct v3d_compiler *compiler,
char *shaderdb;
int ret = asprintf(&shaderdb,
"%s shader: %d inst, %d threads, %d loops, "
- "%d uniforms, %d max-temps, %d:%d spills:fills",
+ "%d uniforms, %d max-temps, %d:%d spills:fills, "
+ "%d sfu-stalls, %d inst-and-stalls",
vir_get_stage_name(c),
c->qpu_inst_count,
c->threads,
@@ -955,7 +956,9 @@ uint64_t *v3d_compile(const struct v3d_compiler *compiler,
c->num_uniforms,
vir_get_max_temps(c),
c->spills,
- c->fills);
+ c->fills,
+ c->qpu_inst_stalled_count,
+ c->qpu_inst_count + c->qpu_inst_stalled_count);
if (ret >= 0) {
if (V3D_DEBUG & V3D_DEBUG_SHADERDB)
fprintf(stderr, "SHADER-DB: %s\n", shaderdb);
diff --git a/src/broadcom/qpu/qpu_instr.c b/src/broadcom/qpu/qpu_instr.c
index 66e53a6..09d06b3 100644
--- a/src/broadcom/qpu/qpu_instr.c
+++ b/src/broadcom/qpu/qpu_instr.c
@@ -645,19 +645,10 @@ v3d_qpu_uses_tlb(const struct v3d_qpu_instr *inst)
bool
v3d_qpu_uses_sfu(const struct v3d_qpu_instr *inst)
{
- if (inst->type == V3D_QPU_INSTR_TYPE_ALU) {
- switch (inst->alu.add.op) {
- case V3D_QPU_A_RECIP:
- case V3D_QPU_A_RSQRT:
- case V3D_QPU_A_EXP:
- case V3D_QPU_A_LOG:
- case V3D_QPU_A_SIN:
- case V3D_QPU_A_RSQRT2:
- return true;
- default:
- break;
- }
+ if (v3d_qpu_instr_is_sfu(inst))
+ return true;
+ if (inst->type == V3D_QPU_INSTR_TYPE_ALU) {
if (inst->alu.add.magic_write &&
v3d_qpu_magic_waddr_is_sfu(inst->alu.add.waddr)) {
return true;
@@ -673,6 +664,25 @@ v3d_qpu_uses_sfu(const struct v3d_qpu_instr *inst)
}
bool
+v3d_qpu_instr_is_sfu(const struct v3d_qpu_instr *inst)
+{
+ if (inst->type == V3D_QPU_INSTR_TYPE_ALU) {
+ switch (inst->alu.add.op) {
+ case V3D_QPU_A_RECIP:
+ case V3D_QPU_A_RSQRT:
+ case V3D_QPU_A_EXP:
+ case V3D_QPU_A_LOG:
+ case V3D_QPU_A_SIN:
+ case V3D_QPU_A_RSQRT2:
+ return true;
+ default:
+ return false;
+ }
+ }
+ return false;
+}
+
+bool
v3d_qpu_writes_tmu(const struct v3d_qpu_instr *inst)
{
return (inst->type == V3D_QPU_INSTR_TYPE_ALU &&
diff --git a/src/broadcom/qpu/qpu_instr.h b/src/broadcom/qpu/qpu_instr.h
index 968d0f6..ad2d37b 100644
--- a/src/broadcom/qpu/qpu_instr.h
+++ b/src/broadcom/qpu/qpu_instr.h
@@ -447,6 +447,7 @@ bool v3d_qpu_magic_waddr_is_vpm(enum v3d_qpu_waddr waddr) ATTRIBUTE_CONST;
bool v3d_qpu_magic_waddr_is_tsy(enum v3d_qpu_waddr waddr) ATTRIBUTE_CONST;
bool v3d_qpu_magic_waddr_loads_unif(enum v3d_qpu_waddr waddr) ATTRIBUTE_CONST;
bool v3d_qpu_uses_tlb(const struct v3d_qpu_instr *inst) ATTRIBUTE_CONST;
+bool v3d_qpu_instr_is_sfu(const struct v3d_qpu_instr *inst) ATTRIBUTE_CONST;
bool v3d_qpu_uses_sfu(const struct v3d_qpu_instr *inst) ATTRIBUTE_CONST;
bool v3d_qpu_writes_tmu(const struct v3d_qpu_instr *inst) ATTRIBUTE_CONST;
bool v3d_qpu_writes_tmu_not_tmuc(const struct v3d_qpu_instr *inst) ATTRIBUTE_CONST;