[Mesa-dev] [PATCH] r600/sb: give the scheduler more margin to find valid instructions groups

[Gert Wollny]

For instruction sequences that change the address register with every load
the current limit to bail out of the scheduler and reject the optimisation
was too tight, i.e. it was expected that at least one pending instruction
would be scheduled each time.

Give the scheduler more margin to sort out these load sequences by allowing
a number of rounds where no instruction is scheduled.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=106163

Signed-off-by: Gert Wollny <gw.fossdev at gmail.com>
---
 src/gallium/drivers/r600/sb/sb_sched.cpp | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/src/gallium/drivers/r600/sb/sb_sched.cpp b/src/gallium/drivers/r600/sb/sb_sched.cpp
index ffc66018b1..d37db99a55 100644
--- a/src/gallium/drivers/r600/sb/sb_sched.cpp
+++ b/src/gallium/drivers/r600/sb/sb_sched.cpp
@@ -1154,14 +1154,21 @@ bool post_scheduler::schedule_alu(container_node *c) {
 
 	assert(!ready.empty() || !ready_copies.empty());
 
-	bool improving = true;
+	/* This number is rather arbitrary, important is that the scheduler has 
+	 * more than one try to create an instruction group
+	 */
+	int improving = 10;
 	int last_pending = pending.count();
-	while (improving) {
+	while (improving > 0) {
 		prev_regmap = regmap;
 		if (!prepare_alu_group()) {
 
 			int new_pending = pending.count();
-			improving = (new_pending < last_pending) || (last_pending == 0);
+			if ((new_pending < last_pending) || (last_pending == 0))
+				improving = 10;
+			else
+				--improving;
+
 			last_pending = new_pending;
 
 			if (alu.current_idx[0] || alu.current_idx[1]) {
-- 
2.16.1