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

arch/powerpc/boot/Makefile

+3 −1
Original line number Original line Diff line number Diff line
@@ -20,7 +20,7 @@ 
all: $(obj)/zImage

all: $(obj)/zImage





BOOTCFLAGS    := -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs \

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 \

		 -fomit-frame-pointer -fno-builtin -fPIC -nostdinc \

		 -isystem $(shell $(CROSS32CC) -print-file-name=include)

		 -isystem $(shell $(CROSS32CC) -print-file-name=include)

BOOTAFLAGS	:= -D__ASSEMBLY__ $(BOOTCFLAGS) -traditional -nostdinc

BOOTAFLAGS	:= -D__ASSEMBLY__ $(BOOTCFLAGS) -traditional -nostdinc
@@ -34,6 +34,8 @@ BOOTCFLAGS += -fno-stack-protector 
endif

endif





BOOTCFLAGS	+= -I$(obj) -I$(srctree)/$(obj)

BOOTCFLAGS	+= -I$(obj) -I$(srctree)/$(obj)

BOOTCFLAGS	+= -include include/linux/autoconf.h -Iarch/powerpc/include

BOOTCFLAGS	+= -Iinclude





DTS_FLAGS	?= -p 1024

DTS_FLAGS	?= -p 1024

lib/zlib_inflate/inffast.c

+44 −11
Original line number Original line Diff line number Diff line
@@ -4,6 +4,8 @@ 
 */

 */





#include <linux/zutil.h>

#include <linux/zutil.h>

#include <asm/unaligned.h>

#include <asm/byteorder.h>

#include "inftrees.h"

#include "inftrees.h"

#include "inflate.h"

#include "inflate.h"

#include "inffast.h"

#include "inffast.h"
@@ -24,9 +26,11 @@ 
#ifdef POSTINC

#ifdef POSTINC

#  define OFF 0

#  define OFF 0

#  define PUP(a) *(a)++

#  define PUP(a) *(a)++

#  define UP_UNALIGNED(a) get_unaligned((a)++)

#else

#else

#  define OFF 1

#  define OFF 1

#  define PUP(a) *++(a)

#  define PUP(a) *++(a)

#  define UP_UNALIGNED(a) get_unaligned(++(a))

#endif

#endif





/*

/*
@@ -239,18 +243,47 @@ void inflate_fast(z_streamp strm, unsigned start) 
                    }

                    }

                }

                }

                else {

                else {

		    unsigned short *sout;

		    unsigned long loops;



                    from = out - dist;          /* copy direct from output */

                    from = out - dist;          /* copy direct from output */

                    do {                        /* minimum length is three */

		    /* minimum length is three */

                        PUP(out) = PUP(from);

		    /* Align out addr */

                        PUP(out) = PUP(from);

		    if (!((long)(out - 1 + OFF) & 1)) {

                        PUP(out) = PUP(from);

                        len -= 3;

                    } while (len > 2);

                    if (len) {

                        PUP(out) = PUP(from);

                        if (len > 1)

			PUP(out) = PUP(from);

			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 */

            else if ((op & 64) == 0) {          /* 2nd level distance code */

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