zlib: optimize inffast when copying direct from output

JFFS2 uses lesser compression ratio and inflate always ends up in "copy direct from output" case. This patch tries to optimize the direct copy procedure. Uses get_unaligned() but only in one place. The copy loop just above this one can also use this optimization, but I havn't done so as I have not tested if it is a win there too. On my MPC8321 this is about 17% faster on my JFFS2 root FS than the original. [[email protected]: coding-style fixes] Signed-off-by: Joakim Tjernlund <[email protected]> Cc: Roel Kluin <[email protected]> Cc: Richard Purdie <[email protected]> Cc: David Woodhouse <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
torvalds · Jan 11, 2010 · ac4c2a3 · ac4c2a3
1 parent 129182e
commit ac4c2a3
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Showing 2 changed files with 47 additions and 12 deletions.
diff --git a/arch/powerpc/boot/Makefile b/arch/powerpc/boot/Makefile
@@ -20,7 +20,7 @@
 all: $(obj)/zImage
 
 BOOTCFLAGS    := -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs \
-		 -fno-strict-aliasing -Os -msoft-float -pipe \
+		 -fno-strict-aliasing -Os -msoft-float -pipe -D__KERNEL__\
 		 -fomit-frame-pointer -fno-builtin -fPIC -nostdinc \
 		 -isystem $(shell $(CROSS32CC) -print-file-name=include)
 BOOTAFLAGS	:= -D__ASSEMBLY__ $(BOOTCFLAGS) -traditional -nostdinc
@@ -34,6 +34,8 @@ BOOTCFLAGS	+= -fno-stack-protector
 endif
 
 BOOTCFLAGS	+= -I$(obj) -I$(srctree)/$(obj)
+BOOTCFLAGS	+= -include include/linux/autoconf.h -Iarch/powerpc/include
+BOOTCFLAGS	+= -Iinclude
 
 DTS_FLAGS	?= -p 1024
 

diff --git a/lib/zlib_inflate/inffast.c b/lib/zlib_inflate/inffast.c
@@ -4,6 +4,8 @@
  */
 
 #include <linux/zutil.h>
+#include <asm/unaligned.h>
+#include <asm/byteorder.h>
 #include "inftrees.h"
 #include "inflate.h"
 #include "inffast.h"
@@ -24,9 +26,11 @@
 #ifdef POSTINC
 #  define OFF 0
 #  define PUP(a) *(a)++
+#  define UP_UNALIGNED(a) get_unaligned((a)++)
 #else
 #  define OFF 1
 #  define PUP(a) *++(a)
+#  define UP_UNALIGNED(a) get_unaligned(++(a))
 #endif
 
 /*
@@ -239,18 +243,47 @@ void inflate_fast(z_streamp strm, unsigned start)
                     }
                 }
                 else {
+		    unsigned short *sout;
+		    unsigned long loops;
+
                     from = out - dist;          /* copy direct from output */
-                    do {                        /* minimum length is three */
-                        PUP(out) = PUP(from);
-                        PUP(out) = PUP(from);
-                        PUP(out) = PUP(from);
-                        len -= 3;
-                    } while (len > 2);
-                    if (len) {
-                        PUP(out) = PUP(from);
-                        if (len > 1)
-                            PUP(out) = PUP(from);
-                    }
+		    /* minimum length is three */
+		    /* Align out addr */
+		    if (!((long)(out - 1 + OFF) & 1)) {
+			PUP(out) = PUP(from);
+			len--;
+		    }
+		    sout = (unsigned short *)(out - OFF);
+		    if (dist > 2) {
+			unsigned short *sfrom;
+
+			sfrom = (unsigned short *)(from - OFF);
+			loops = len >> 1;
+			do
+			    PUP(sout) = UP_UNALIGNED(sfrom);
+			while (--loops);
+			out = (unsigned char *)sout + OFF;
+			from = (unsigned char *)sfrom + OFF;
+		    } else { /* dist == 1 or dist == 2 */
+			unsigned short pat16;
+
+			pat16 = *(sout-2+2*OFF);
+			if (dist == 1)
+#if defined(__BIG_ENDIAN)
+			    pat16 = (pat16 & 0xff) | ((pat16 & 0xff) << 8);
+#elif defined(__LITTLE_ENDIAN)
+			    pat16 = (pat16 & 0xff00) | ((pat16 & 0xff00) >> 8);
+#else
+#error __BIG_ENDIAN nor __LITTLE_ENDIAN is defined
+#endif
+			loops = len >> 1;
+			do
+			    PUP(sout) = pat16;
+			while (--loops);
+			out = (unsigned char *)sout + OFF;
+		    }
+		    if (len & 1)
+			PUP(out) = PUP(from);
                 }
             }
             else if ((op & 64) == 0) {          /* 2nd level distance code */