2 files changed, 89 insertions, 15 deletions

diff --git a/src/gallium/drivers/r600/sb/sb_pass.h b/src/gallium/drivers/r600/sb/sb_pass.h
index c3ea8734de3..95d2a203a60 100644
--- a/src/gallium/drivers/r600/sb/sb_pass.h
+++ b/src/gallium/drivers/r600/sb/sb_pass.h
@@ -507,12 +507,36 @@ class ra_init : public pass {
 
 public:
 
-	ra_init(shader &sh) : pass(sh) {}
+	ra_init(shader &sh) : pass(sh), prev_chans() {
+
+		// The parameter below affects register channels distribution.
+		// For cayman (VLIW-4) we're trying to distribute the channels
+		// uniformly, this means significantly better alu slots utilization
+		// at the expense of higher gpr usage. Hopefully this will improve
+		// performance, though it has to be proven with real benchmarks yet.
+		// For VLIW-5 this method could also slightly improve slots
+		// utilization, but increased register pressure seems more significant
+		// and overall performance effect is negative according to some
+		// benchmarks, so it's not used currently. Basically, VLIW-5 doesn't
+		// really need it because trans slot (unrestricted by register write
+		// channel) allows to consume most deviations from uniform channel
+		// distribution.
+		// Value 3 means that for new allocation we'll use channel that differs
+		// from 3 last used channels. 0 for VLIW-5 effectively turns this off.
+
+		ra_tune = sh.get_ctx().is_cayman() ? 3 : 0;
+	}
 
 	virtual int run();
 
 private:
 
+	unsigned prev_chans;
+	unsigned ra_tune;
+
+	void add_prev_chan(unsigned chan);
+	unsigned get_preferable_chan_mask();
+
 	void ra_node(container_node *c);
 	void process_op(node *n);
 
diff --git a/src/gallium/drivers/r600/sb/sb_ra_init.cpp b/src/gallium/drivers/r600/sb/sb_ra_init.cpp
index 24b24a0bde3..0b332a9847a 100644
--- a/src/gallium/drivers/r600/sb/sb_ra_init.cpp
+++ b/src/gallium/drivers/r600/sb/sb_ra_init.cpp
@@ -72,6 +72,7 @@ public:
 
 	sel_chan find_free_bit();
 	sel_chan find_free_chans(unsigned mask);
+	sel_chan find_free_chan_by_mask(unsigned mask);
 	sel_chan find_free_array(unsigned size, unsigned mask);
 
 	void dump();
@@ -86,7 +87,7 @@ void regbits::dump() {
 			sblog << "\n";
 
 		if (!(i & 3)) {
-			sblog.print_wl(i / 4, 7);
+			sblog.print_w(i / 4, 7);
 			sblog << " ";
 		}
 
@@ -186,34 +187,64 @@ sel_chan regbits::find_free_chans(unsigned mask) {
 	unsigned elt = 0;
 	unsigned bit = 0;
 
-	basetype cd = dta[elt] >> bit;
+	assert (!(mask & ~0xF));
+	basetype cd = dta[elt];
 
 	do {
-
 		if (!cd) {
-			if (++elt < size)
+			if (++elt < size) {
 				cd = dta[elt];
-			else
+				bit = 0;
+				continue;
+			} else
 				return 0;
-
-			bit = 0;
 		}
 
 		unsigned p = __builtin_ctz(cd) & ~(basetype)3u;
 
-		if (p > bt_bits - bit) {
-			if (++elt < size)
+		assert (p <= bt_bits - bit);
+		bit += p;
+		cd >>= p;
+
+		if ((cd & mask) == mask) {
+			return ((elt << bt_index_shift) | bit) + 1;
+		}
+
+		bit += 4;
+		cd >>= 4;
+
+	} while (1);
+
+	return 0;
+}
+
+sel_chan regbits::find_free_chan_by_mask(unsigned mask) {
+	unsigned elt = 0;
+	unsigned bit = 0;
+
+	assert (!(mask & ~0xF));
+	basetype cd = dta[elt];
+
+	do {
+		if (!cd) {
+			if (++elt < size) {
 				cd = dta[elt];
-			else
+				bit = 0;
+				continue;
+			} else
 				return 0;
-			bit = 0;
 		}
 
+		unsigned p = __builtin_ctz(cd) & ~(basetype)3u;
+
+		assert (p <= bt_bits - bit);
 		bit += p;
 		cd >>= p;
 
-		if ((cd & mask) == mask) {
-			return ((elt << bt_index_shift) | bit) + 1;
+		if (cd & mask) {
+			unsigned nb = __builtin_ctz(cd & mask);
+			unsigned ofs = ((elt << bt_index_shift) | bit);
+			return nb + ofs + 1;
 		}
 
 		bit += 4;
@@ -476,7 +507,9 @@ void ra_init::color(value* v) {
 		unsigned mask = 1 << v->pin_gpr.chan();
 		c = rb.find_free_chans(mask) + v->pin_gpr.chan();
 	} else {
-		c = rb.find_free_bit();
+		unsigned cm = get_preferable_chan_mask();
+		RA_DUMP( sblog << "pref chan mask: " << cm << "\n"; );
+		c = rb.find_free_chan_by_mask(cm);
 	}
 
 	assert(c && c.sel() < 128 - ctx.alu_temp_gprs && "color failed");
@@ -484,6 +517,7 @@ void ra_init::color(value* v) {
 }
 
 void ra_init::assign_color(value* v, sel_chan c) {
+	add_prev_chan(c.chan());
 	v->gpr = c;
 	RA_DUMP(
 		sblog << "colored ";
@@ -790,4 +824,20 @@ void ra_split::split_vector_inst(node* n) {
 	}
 }
 
+void ra_init::add_prev_chan(unsigned chan) {
+	prev_chans = (prev_chans << 4) | (1 << chan);
+}
+
+unsigned ra_init::get_preferable_chan_mask() {
+	unsigned i, used_chans = 0;
+	unsigned chans = prev_chans;
+
+	for (i = 0; i < ra_tune; ++i) {
+		used_chans |= chans;
+		chans >>= 4;
+	}
+
+	return (~used_chans) & 0xF;
+}
+
 } // namespace r600_sb