Commit ac4c2a3b authored by Joakim Tjernlund's avatar Joakim Tjernlund Committed by Linus Torvalds

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.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: default avatarJoakim Tjernlund <Joakim.Tjernlund@transmode.se>
Cc: Roel Kluin <roel.kluin@gmail.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 129182e5
......@@ -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
......
......@@ -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 */
......
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