sna: Flush BLT operations to an idle GPU

We improve dispatch latency if after creating a command buffer we
immediately submit if the GPU is idle. This improves concurrency as we
continue to build the next command buffer as the GPU executes and helps
prevent needlessly using one engine for too long (i.e. sometimes we may
be able to execute the work much early and do the ring switch cheaply).

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 22 insertions, 12 deletions

diff --git a/src/sna/sna_accel.c b/src/sna/sna_accel.c
index 0bd3bb60..9b84d5c6 100644
--- a/src/sna/sna_accel.c
+++ b/src/sna/sna_accel.c
@@ -5228,6 +5228,16 @@ static inline uint8_t blt_depth(int depth)
 	}
 }
 
+inline static void blt_done(struct sna *sna)
+{
+	sna->blt_state.fill_bo = 0;
+	if (sna->kgem.nbatch && __kgem_ring_empty(&sna->kgem)) {
+		DBG(("%s: flushing BLT operation on empty ring\n",
+		     __FUNCTION__));
+		_kgem_submit(&sna->kgem);
+	}
+}
+
 static bool
 sna_put_xybitmap_blt(DrawablePtr drawable, GCPtr gc, RegionPtr region,
 		     int x, int y, int w, int  h, char *bits)
@@ -5387,7 +5397,7 @@ sna_put_xybitmap_blt(DrawablePtr drawable, GCPtr gc, RegionPtr region,
 		box++;
 	} while (--n);
 
-	sna->blt_state.fill_bo = 0;
+	blt_done(sna);
 	return true;
 }
 
@@ -5565,7 +5575,7 @@ sna_put_xypixmap_blt(DrawablePtr drawable, GCPtr gc, RegionPtr region,
 		} while (--n);
 	}
 
-	sna->blt_state.fill_bo = 0;
+	blt_done(sna);
 	return true;
 }
 
@@ -8467,7 +8477,7 @@ sna_copy_bitmap_blt(DrawablePtr _bitmap, DrawablePtr drawable, GCPtr gc,
 		sna_damage_add_to_pixmap(arg->damage, region, pixmap);
 	}
 	assert_pixmap_damage(pixmap);
-	sna->blt_state.fill_bo = 0;
+	blt_done(sna);
 }
 
 static void
@@ -8700,7 +8710,7 @@ sna_copy_plane_blt(DrawablePtr source, DrawablePtr drawable, GCPtr gc,
 		sna_damage_add_to_pixmap(arg->damage, region, dst_pixmap);
 	}
 	assert_pixmap_damage(dst_pixmap);
-	sna->blt_state.fill_bo = 0;
+	blt_done(sna);
 }
 
 static RegionPtr
@@ -12661,7 +12671,7 @@ sna_poly_fill_rect_tiled_8x8_blt(DrawablePtr drawable,
 	}
 done:
 	assert_pixmap_damage(pixmap);
-	sna->blt_state.fill_bo = 0;
+	blt_done(sna);
 	return true;
 }
 
@@ -13508,7 +13518,7 @@ sna_poly_fill_rect_stippled_8x8_blt(DrawablePtr drawable,
 	}
 
 	assert_pixmap_damage(pixmap);
-	sna->blt_state.fill_bo = 0;
+	blt_done(sna);
 	return true;
 }
 
@@ -14153,7 +14163,7 @@ sna_poly_fill_rect_stippled_1_blt(DrawablePtr drawable,
 		}
 	}
 
-	sna->blt_state.fill_bo = 0;
+	blt_done(sna);
 	return true;
 }
 
@@ -14615,7 +14625,7 @@ sna_poly_fill_rect_stippled_n_blt__imm(DrawablePtr drawable,
 	}
 
 	assert_pixmap_damage(pixmap);
-	sna->blt_state.fill_bo = 0;
+	blt_done(sna);
 	return true;
 }
 
@@ -14762,7 +14772,7 @@ sna_poly_fill_rect_stippled_n_blt(DrawablePtr drawable,
 	assert_pixmap_damage(pixmap);
 	if (tile)
 		kgem_bo_destroy(&sna->kgem, tile);
-	sna->blt_state.fill_bo = 0;
+	blt_done(sna);
 	return true;
 }
 
@@ -15568,7 +15578,7 @@ skip:
 	}
 
 	assert_pixmap_damage(pixmap);
-	sna->blt_state.fill_bo = 0;
+	blt_done(sna);
 	return true;
 }
 
@@ -16318,7 +16328,7 @@ skip:
 	}
 
 	assert_pixmap_damage(pixmap);
-	sna->blt_state.fill_bo = 0;
+	blt_done(sna);
 	return true;
 }
 
@@ -16653,7 +16663,7 @@ sna_push_pixels_solid_blt(GCPtr gc,
 		box++;
 	} while (--n);
 
-	sna->blt_state.fill_bo = 0;
+	blt_done(sna);
 	return true;
 }