svn commit: r265864 - head/sys/dev/vt/hw/ofwfb

[Nathan Whitehorn]

Author: nwhitehorn
Date: Sun May 11 01:58:56 2014
New Revision: 265864
URL: http://svnweb.freebsd.org/changeset/base/265864

Log:
  Make ofwfb not be painfully slow. This reduces the time for a verbose boot
  on my G4 iBook by more than half. Still 10% slower than syscons, but that's
  much better than a factor of 2.
  
  The slowness had to do with pathological write performance on 8-bit
  framebuffers, which are almost universally used on Open Firmware systems.
  Writing 1 byte at a time, potentially nonconsecutively, resulted in many
  extra PCI write cycles. This patch, in the common case where it's writing
  one or several characters in an 8x8 font, gangs the writes together into
  a set of 32-bit writes. This is a port of r143830 to vt(4).
  
  The EFI framebuffer is also extremely slow, probably for the same reason,
  and the same patch will likely help there.

Modified:
  head/sys/dev/vt/hw/ofwfb/ofwfb.c

Modified: head/sys/dev/vt/hw/ofwfb/ofwfb.c
==============================================================================
--- head/sys/dev/vt/hw/ofwfb/ofwfb.c	Sun May 11 01:44:11 2014	(r265863)
+++ head/sys/dev/vt/hw/ofwfb/ofwfb.c	Sun May 11 01:58:56 2014	(r265864)
@@ -136,6 +136,10 @@ ofwfb_bitbltchr(struct vt_device *vd, co
 	uint32_t fgc, bgc;
 	int c;
 	uint8_t b, m;
+	union {
+		uint32_t l;
+		uint8_t	 c[4];
+	} ch1, ch2;
 
 	fgc = sc->sc_colormap[fg];
 	bgc = sc->sc_colormap[bg];
@@ -147,36 +151,70 @@ ofwfb_bitbltchr(struct vt_device *vd, co
 		return;
 
 	line = (sc->sc_stride * top) + left * sc->sc_depth/8;
-	for (; height > 0; height--) {
-		for (c = 0; c < width; c++) {
-			if (c % 8 == 0)
+	if (mask == NULL && sc->sc_depth == 8 && (width % 8 == 0)) {
+		for (; height > 0; height--) {
+			for (c = 0; c < width; c += 8) {
 				b = *src++;
-			else
-				b <<= 1;
-			if (mask != NULL) {
+
+				/*
+				 * Assume that there is more background than
+				 * foreground in characters and init accordingly
+				 */
+				ch1.l = ch2.l = (bg << 24) | (bg << 16) |
+				    (bg << 8) | bg;
+
+				/*
+				 * Calculate 2 x 4-chars at a time, and then
+				 * write these out.
+				 */
+				if (b & 0x80) ch1.c[0] = fg;
+				if (b & 0x40) ch1.c[1] = fg;
+				if (b & 0x20) ch1.c[2] = fg;
+				if (b & 0x10) ch1.c[3] = fg;
+
+				if (b & 0x08) ch2.c[0] = fg;
+				if (b & 0x04) ch2.c[1] = fg;
+				if (b & 0x02) ch2.c[2] = fg;
+				if (b & 0x01) ch2.c[3] = fg;
+
+				*(uint32_t *)(sc->sc_addr + line + c) = ch1.l;
+				*(uint32_t *)(sc->sc_addr + line + c + 4) =
+				    ch2.l;
+			}
+			line += sc->sc_stride;
+		}
+	} else {
+		for (; height > 0; height--) {
+			for (c = 0; c < width; c++) {
 				if (c % 8 == 0)
-					m = *mask++;
+					b = *src++;
 				else
-					m <<= 1;
-				/* Skip pixel write, if mask has no bit set. */
-				if ((m & 0x80) == 0)
-					continue;
-			}
-			switch(sc->sc_depth) {
-			case 8:
-				*(uint8_t *)(sc->sc_addr + line + c) =
-				    b & 0x80 ? fg : bg;
-				break;
-			case 32:
-				*(uint32_t *)(sc->sc_addr + line + 4*c) = 
-				    (b & 0x80) ? fgc : bgc;
-				break;
-			default:
-				/* panic? */
-				break;
+					b <<= 1;
+				if (mask != NULL) {
+					if (c % 8 == 0)
+						m = *mask++;
+					else
+						m <<= 1;
+					/* Skip pixel write, if mask not set. */
+					if ((m & 0x80) == 0)
+						continue;
+				}
+				switch(sc->sc_depth) {
+				case 8:
+					*(uint8_t *)(sc->sc_addr + line + c) =
+					    b & 0x80 ? fg : bg;
+					break;
+				case 32:
+					*(uint32_t *)(sc->sc_addr + line + 4*c)
+					    = (b & 0x80) ? fgc : bgc;
+					break;
+				default:
+					/* panic? */
+					break;
+				}
 			}
+			line += sc->sc_stride;
 		}
-		line += sc->sc_stride;
 	}
 }