[PATCH] zlib: Optimize inffast even more

This improves zlib: Optimize inffast when copying direct from output
and gives another 3-4% improvement for my MPC8321 target.
Does not need CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS,
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.

Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund.TakeThisOut@transmode.se>
---

Someone with a little endian target should test too.

arch/powerpc/boot/Makefile | 1 +
lib/zlib_inflate/inffast.c | 54 ++++++++++++++++++++++----------------------
2 files changed, 28 insertions(+), 27 deletions(-)

diff --git a/arch/powerpc/boot/Makefile b/arch/powerpc/boot/Makefile
index 9ae7b7e..33335be 100644
--- a/arch/powerpc/boot/Makefile
+++ b/arch/powerpc/boot/Makefile
@@ -34,6 +34,7 @@ BOOTCFLAGS += -fno-stack-protector
endif

BOOTCFLAGS += -I$(obj) -I$(srctree)/$(obj)
+BOOTCFLAGS += -Iarch/powerpc/include

DTS_FLAGS ?= -p 1024

diff --git a/lib/zlib_inflate/inffast.c b/lib/zlib_inflate/inffast.c
index 0588fbf..4f78567 100644
--- a/lib/zlib_inflate/inffast.c
+++ b/lib/zlib_inflate/inffast.c
@@ -4,6 +4,7 @@
*/

#include <linux/zutil.h>
+#include <asm/unaligned.h>
#include "inftrees.h"
#include "inflate.h"
#include "inffast.h"
@@ -24,9 +25,11 @@
#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

/*
@@ -240,52 +243,49 @@ void inflate_fast(z_streamp strm, unsigned start)
}
else {
from = out - dist; /* copy direct from output */
-#ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
/* minimum length is three */
if (dist > 2 ) {
- unsigned short *sout = (unsigned short *)(out - OFF);
- unsigned short *sfrom = (unsigned short *)(from - OFF);
- unsigned long loops = len >> 1;
+ unsigned short *sout;
+ unsigned short *sfrom;
+ unsigned long loops;

+ /* Align out addr, only sfrom might be unaligned */
+ if (!((long)(out - 1 + OFF)) & 1) {
+ PUP(out) = PUP(from);
+ len--;
+ }
+ sout = (unsigned short *)(out - OFF);
+ sfrom = (unsigned short *)(from - OFF);
+ loops = len >> 1;
do
- PUP(sout) = PUP(sfrom);
+ PUP(sout) = UP_UNALIGNED(sfrom);
while (--loops);
out = (unsigned char *)sout + OFF;
from = (unsigned char *)sfrom + OFF;
if (len & 1)
PUP(out) = PUP(from);
- } else if (dist == 2) {
- unsigned short *sout = (unsigned short *)(out - OFF);
+ } else { /* dist == 1 or dist == 2 */
+ unsigned short *sout;
unsigned short pat16;
- unsigned long loops = len >> 1;
+ unsigned long loops;

+ /* Align out addr */
+ if (!((long)(out - 1 + OFF)) & 1) {
+ PUP(out) = PUP(from);
+ len--;
+ }
+ sout = (unsigned short *)(out - OFF);
pat16 = *(sout-2+2*OFF);
+ if (dist == 1)
+ pat16 = (pat16 & 0xff) | ((pat16 & 0xff ) << ;
+ loops = len >> 1;
do
PUP(sout) = pat16;
while (--loops);
out = (unsigned char *)sout + OFF;
if (len & 1)
PUP(out) = PUP(from);
- } else {
- unsigned char pat8 = *(out - 1 + OFF);
-
- do {
- PUP(out) = pat8;
- } while (--len);
}
-#else
- 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);
- }
-#endif
}
}
else if ((op & 64) == 0) { /* 2nd level distance code */
--
1.6.4.4

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On Mon, 9 Nov 2009 11:22:16 +0100
Joakim Tjernlund <Joakim.Tjernlund RemoveThis @transmode.se> wrote:

> This improves zlib: Optimize inffast when copying direct from output
> and gives another 3-4% improvement for my MPC8321 target.
> Does not need CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS,
> 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.
>
> Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund RemoveThis @transmode.se>
> ---
>
> Someone with a little endian target should test too.

eh? That requires a PC. Can't you test it??
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