[Mesa-dev] [PATCH] i965: Improve conditional rendering in fallback paths.
Kenneth Graunke
kenneth at whitecape.org
Thu Mar 2 08:06:00 UTC 2017
We need to fall back in a couple of cases:
- Sandybridge (it just doesn't do this in hardware)
- Occlusion queries on Gen7-7.5 with command parser version < 2
- Transform feedback overflow queries on Gen7, or on Gen7.5 with
command parser version < 7
In these cases, we printed a perf_debug message and fell back to
_mesa_check_conditional_render(), which stalls until the full
query result is available. Additionally, the code to handle this
was a bit of a mess.
We can do better by using our normal conditional rendering code,
and setting a new state, BRW_PREDICATE_STATE_STALL_FOR_QUERY, when
we would have set BRW_PREDICATE_STATE_USE_BIT. Only if that state
is set do we perf_debug and potentially stall. This means we avoid
stalls when we have a partial query result (i.e. we know it's > 0,
but don't have the full value). The perf_debug should trigger less
often as well.
Still, this is primarily intended as a cleanup.
Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
---
src/mesa/drivers/dri/i965/brw_conditional_render.c | 84 +++++++++++-----------
src/mesa/drivers/dri/i965/brw_context.c | 3 +-
src/mesa/drivers/dri/i965/brw_context.h | 6 +-
3 files changed, 48 insertions(+), 45 deletions(-)
diff --git a/src/mesa/drivers/dri/i965/brw_conditional_render.c b/src/mesa/drivers/dri/i965/brw_conditional_render.c
index 046a42b5f52..c9503c5343d 100644
--- a/src/mesa/drivers/dri/i965/brw_conditional_render.c
+++ b/src/mesa/drivers/dri/i965/brw_conditional_render.c
@@ -52,6 +52,19 @@ set_predicate_for_overflow_query(struct brw_context *brw,
struct brw_query_object *query,
int stream_start, int count)
{
+ if (!can_do_mi_math_and_lrr(brw->screen)) {
+ brw->predicate.state = BRW_PREDICATE_STATE_STALL_FOR_QUERY;
+ return;
+ }
+
+ brw->predicate.state = BRW_PREDICATE_STATE_USE_BIT;
+
+ /* Needed to ensure the memory is coherent for the MI_LOAD_REGISTER_MEM
+ * command when loading the values into the predicate source registers for
+ * conditional rendering.
+ */
+ brw_emit_pipe_control_flush(brw, PIPE_CONTROL_FLUSH_ENABLE);
+
hsw_overflow_result_to_gpr0(brw, query, count);
brw_load_register_reg64(brw, HSW_CS_GPR(0), MI_PREDICATE_SRC0);
brw_load_register_imm64(brw, MI_PREDICATE_SRC1, 0ull);
@@ -61,6 +74,19 @@ static void
set_predicate_for_occlusion_query(struct brw_context *brw,
struct brw_query_object *query)
{
+ if (!brw->predicate.supported) {
+ brw->predicate.state = BRW_PREDICATE_STATE_STALL_FOR_QUERY;
+ return;
+ }
+
+ brw->predicate.state = BRW_PREDICATE_STATE_USE_BIT;
+
+ /* Needed to ensure the memory is coherent for the MI_LOAD_REGISTER_MEM
+ * command when loading the values into the predicate source registers for
+ * conditional rendering.
+ */
+ brw_emit_pipe_control_flush(brw, PIPE_CONTROL_FLUSH_ENABLE);
+
brw_load_register_mem64(brw,
MI_PREDICATE_SRC0,
query->bo,
@@ -80,17 +106,10 @@ set_predicate_for_result(struct brw_context *brw,
struct brw_query_object *query,
bool inverted)
{
-
int load_op;
assert(query->bo != NULL);
- /* Needed to ensure the memory is coherent for the MI_LOAD_REGISTER_MEM
- * command when loading the values into the predicate source registers for
- * conditional rendering.
- */
- brw_emit_pipe_control_flush(brw, PIPE_CONTROL_FLUSH_ENABLE);
-
switch (query->Base.Target) {
case GL_TRANSFORM_FEEDBACK_STREAM_OVERFLOW_ARB:
set_predicate_for_overflow_query(brw, query, 0, 1);
@@ -102,19 +121,19 @@ set_predicate_for_result(struct brw_context *brw,
set_predicate_for_occlusion_query(brw, query);
}
- if (inverted)
- load_op = MI_PREDICATE_LOADOP_LOAD;
- else
- load_op = MI_PREDICATE_LOADOP_LOADINV;
-
- BEGIN_BATCH(1);
- OUT_BATCH(GEN7_MI_PREDICATE |
- load_op |
- MI_PREDICATE_COMBINEOP_SET |
- MI_PREDICATE_COMPAREOP_SRCS_EQUAL);
- ADVANCE_BATCH();
-
- brw->predicate.state = BRW_PREDICATE_STATE_USE_BIT;
+ if (brw->predicate.state == BRW_PREDICATE_STATE_USE_BIT) {
+ if (inverted)
+ load_op = MI_PREDICATE_LOADOP_LOAD;
+ else
+ load_op = MI_PREDICATE_LOADOP_LOADINV;
+
+ BEGIN_BATCH(1);
+ OUT_BATCH(GEN7_MI_PREDICATE |
+ load_op |
+ MI_PREDICATE_COMBINEOP_SET |
+ MI_PREDICATE_COMPAREOP_SRCS_EQUAL);
+ ADVANCE_BATCH();
+ }
}
static void
@@ -126,14 +145,6 @@ brw_begin_conditional_render(struct gl_context *ctx,
struct brw_query_object *query = (struct brw_query_object *) q;
bool inverted;
- if (!brw->predicate.supported)
- return;
-
- if ((query->Base.Target == GL_TRANSFORM_FEEDBACK_OVERFLOW_ARB ||
- query->Base.Target == GL_TRANSFORM_FEEDBACK_STREAM_OVERFLOW_ARB) &&
- !can_do_mi_math_and_lrr(brw->screen))
- return;
-
switch (mode) {
case GL_QUERY_WAIT:
case GL_QUERY_NO_WAIT:
@@ -185,22 +196,11 @@ brw_check_conditional_render(struct brw_context *brw)
{
const struct gl_query_object *query = brw->ctx.Query.CondRenderQuery;
- const bool query_is_xfb = query &&
- (query->Target == GL_TRANSFORM_FEEDBACK_OVERFLOW_ARB ||
- query->Target == GL_TRANSFORM_FEEDBACK_STREAM_OVERFLOW_ARB);
-
- if (brw->predicate.supported &&
- (can_do_mi_math_and_lrr(brw->screen) || !query_is_xfb)) {
- /* In some cases it is possible to determine that the primitives should
- * be skipped without needing the predicate enable bit and still without
- * stalling.
- */
- return brw->predicate.state != BRW_PREDICATE_STATE_DONT_RENDER;
- } else if (query) {
+ if (brw->predicate.state == BRW_PREDICATE_STATE_STALL_FOR_QUERY) {
perf_debug("Conditional rendering is implemented in software and may "
"stall.\n");
return _mesa_check_conditional_render(&brw->ctx);
- } else {
- return true;
}
+
+ return brw->predicate.state != BRW_PREDICATE_STATE_DONT_RENDER;
}
diff --git a/src/mesa/drivers/dri/i965/brw_context.c b/src/mesa/drivers/dri/i965/brw_context.c
index a676978a98c..a9afb38eeeb 100644
--- a/src/mesa/drivers/dri/i965/brw_context.c
+++ b/src/mesa/drivers/dri/i965/brw_context.c
@@ -459,8 +459,7 @@ brw_init_driver_functions(struct brw_context *brw,
else
gen4_init_queryobj_functions(functions);
brw_init_compute_functions(functions);
- if (brw->gen >= 7)
- brw_init_conditional_render_functions(functions);
+ brw_init_conditional_render_functions(functions);
functions->QueryInternalFormat = brw_query_internal_format;
diff --git a/src/mesa/drivers/dri/i965/brw_context.h b/src/mesa/drivers/dri/i965/brw_context.h
index 8ea7703aa68..7f10faeaaee 100644
--- a/src/mesa/drivers/dri/i965/brw_context.h
+++ b/src/mesa/drivers/dri/i965/brw_context.h
@@ -644,7 +644,11 @@ enum brw_predicate_state {
/* In this case whether to draw or not depends on the result of an
* MI_PREDICATE command so the predicate enable bit needs to be checked.
*/
- BRW_PREDICATE_STATE_USE_BIT
+ BRW_PREDICATE_STATE_USE_BIT,
+ /* In this case, either MI_PREDICATE doesn't exist or we lack the
+ * necessary kernel features to use it. Stall for the query result.
+ */
+ BRW_PREDICATE_STATE_STALL_FOR_QUERY
};
struct shader_times;
--
2.11.1
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