2007-07-11 08:22:24 +08:00
|
|
|
/*
|
2012-08-13 23:25:44 +08:00
|
|
|
* LZO1X Decompressor from LZO
|
2007-07-11 08:22:24 +08:00
|
|
|
*
|
2012-08-13 23:25:44 +08:00
|
|
|
* Copyright (C) 1996-2012 Markus F.X.J. Oberhumer <markus@oberhumer.com>
|
2007-07-11 08:22:24 +08:00
|
|
|
*
|
|
|
|
* The full LZO package can be found at:
|
|
|
|
* http://www.oberhumer.com/opensource/lzo/
|
|
|
|
*
|
2012-08-13 23:25:44 +08:00
|
|
|
* Changed for Linux kernel use by:
|
2007-07-11 08:22:24 +08:00
|
|
|
* Nitin Gupta <nitingupta910@gmail.com>
|
|
|
|
* Richard Purdie <rpurdie@openedhand.com>
|
|
|
|
*/
|
|
|
|
|
lib: add support for LZO-compressed kernels
This patch series adds generic support for creating and extracting
LZO-compressed kernel images, as well as support for using such images on
the x86 and ARM architectures, and support for creating and using
LZO-compressed initrd and initramfs images.
Russell King said:
: Testing on a Cortex A9 model:
: - lzo decompressor is 65% of the time gzip takes to decompress a kernel
: - lzo kernel is 9% larger than a gzip kernel
:
: which I'm happy to say confirms your figures when comparing the two.
:
: However, when comparing your new gzip code to the old gzip code:
: - new is 99% of the size of the old code
: - new takes 42% of the time to decompress than the old code
:
: What this means is that for a proper comparison, the results get even better:
: - lzo is 7.5% larger than the old gzip'd kernel image
: - lzo takes 28% of the time that the old gzip code took
:
: So the expense seems definitely worth the effort. The only reason I
: can think of ever using gzip would be if you needed the additional
: compression (eg, because you have limited flash to store the image.)
:
: I would argue that the default for ARM should therefore be LZO.
This patch:
The lzo compressor is worse than gzip at compression, but faster at
extraction. Here are some figures for an ARM board I'm working on:
Uncompressed size: 3.24Mo
gzip 1.61Mo 0.72s
lzo 1.75Mo 0.48s
So for a compression ratio that is still relatively close to gzip, it's
much faster to extract, at least in that case.
This part contains:
- Makefile routine to support lzo compression
- Fixes to the existing lzo compressor so that it can be used in
compressed kernels
- wrapper around the existing lzo1x_decompress, as it only extracts one
block at a time, while we need to extract a whole file here
- config dialog for kernel compression
[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: cleanup]
Signed-off-by: Albin Tonnerre <albin.tonnerre@free-electrons.com>
Tested-by: Wu Zhangjin <wuzhangjin@gmail.com>
Acked-by: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Russell King <rmk@arm.linux.org.uk>
Acked-by: Russell King <rmk@arm.linux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-01-09 06:42:42 +08:00
|
|
|
#ifndef STATIC
|
2007-07-11 08:22:24 +08:00
|
|
|
#include <linux/module.h>
|
|
|
|
#include <linux/kernel.h>
|
lib: add support for LZO-compressed kernels
This patch series adds generic support for creating and extracting
LZO-compressed kernel images, as well as support for using such images on
the x86 and ARM architectures, and support for creating and using
LZO-compressed initrd and initramfs images.
Russell King said:
: Testing on a Cortex A9 model:
: - lzo decompressor is 65% of the time gzip takes to decompress a kernel
: - lzo kernel is 9% larger than a gzip kernel
:
: which I'm happy to say confirms your figures when comparing the two.
:
: However, when comparing your new gzip code to the old gzip code:
: - new is 99% of the size of the old code
: - new takes 42% of the time to decompress than the old code
:
: What this means is that for a proper comparison, the results get even better:
: - lzo is 7.5% larger than the old gzip'd kernel image
: - lzo takes 28% of the time that the old gzip code took
:
: So the expense seems definitely worth the effort. The only reason I
: can think of ever using gzip would be if you needed the additional
: compression (eg, because you have limited flash to store the image.)
:
: I would argue that the default for ARM should therefore be LZO.
This patch:
The lzo compressor is worse than gzip at compression, but faster at
extraction. Here are some figures for an ARM board I'm working on:
Uncompressed size: 3.24Mo
gzip 1.61Mo 0.72s
lzo 1.75Mo 0.48s
So for a compression ratio that is still relatively close to gzip, it's
much faster to extract, at least in that case.
This part contains:
- Makefile routine to support lzo compression
- Fixes to the existing lzo compressor so that it can be used in
compressed kernels
- wrapper around the existing lzo1x_decompress, as it only extracts one
block at a time, while we need to extract a whole file here
- config dialog for kernel compression
[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: cleanup]
Signed-off-by: Albin Tonnerre <albin.tonnerre@free-electrons.com>
Tested-by: Wu Zhangjin <wuzhangjin@gmail.com>
Acked-by: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Russell King <rmk@arm.linux.org.uk>
Acked-by: Russell King <rmk@arm.linux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-01-09 06:42:42 +08:00
|
|
|
#endif
|
2007-07-11 08:22:24 +08:00
|
|
|
#include <asm/unaligned.h>
|
lib: add support for LZO-compressed kernels
This patch series adds generic support for creating and extracting
LZO-compressed kernel images, as well as support for using such images on
the x86 and ARM architectures, and support for creating and using
LZO-compressed initrd and initramfs images.
Russell King said:
: Testing on a Cortex A9 model:
: - lzo decompressor is 65% of the time gzip takes to decompress a kernel
: - lzo kernel is 9% larger than a gzip kernel
:
: which I'm happy to say confirms your figures when comparing the two.
:
: However, when comparing your new gzip code to the old gzip code:
: - new is 99% of the size of the old code
: - new takes 42% of the time to decompress than the old code
:
: What this means is that for a proper comparison, the results get even better:
: - lzo is 7.5% larger than the old gzip'd kernel image
: - lzo takes 28% of the time that the old gzip code took
:
: So the expense seems definitely worth the effort. The only reason I
: can think of ever using gzip would be if you needed the additional
: compression (eg, because you have limited flash to store the image.)
:
: I would argue that the default for ARM should therefore be LZO.
This patch:
The lzo compressor is worse than gzip at compression, but faster at
extraction. Here are some figures for an ARM board I'm working on:
Uncompressed size: 3.24Mo
gzip 1.61Mo 0.72s
lzo 1.75Mo 0.48s
So for a compression ratio that is still relatively close to gzip, it's
much faster to extract, at least in that case.
This part contains:
- Makefile routine to support lzo compression
- Fixes to the existing lzo compressor so that it can be used in
compressed kernels
- wrapper around the existing lzo1x_decompress, as it only extracts one
block at a time, while we need to extract a whole file here
- config dialog for kernel compression
[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: cleanup]
Signed-off-by: Albin Tonnerre <albin.tonnerre@free-electrons.com>
Tested-by: Wu Zhangjin <wuzhangjin@gmail.com>
Acked-by: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Russell King <rmk@arm.linux.org.uk>
Acked-by: Russell King <rmk@arm.linux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-01-09 06:42:42 +08:00
|
|
|
#include <linux/lzo.h>
|
2007-07-11 08:22:24 +08:00
|
|
|
#include "lzodefs.h"
|
|
|
|
|
2014-06-21 13:00:53 +08:00
|
|
|
#define HAVE_IP(t, x) \
|
|
|
|
(((size_t)(ip_end - ip) >= (size_t)(t + x)) && \
|
|
|
|
(((t + x) >= t) && ((t + x) >= x)))
|
|
|
|
|
|
|
|
#define HAVE_OP(t, x) \
|
|
|
|
(((size_t)(op_end - op) >= (size_t)(t + x)) && \
|
|
|
|
(((t + x) >= t) && ((t + x) >= x)))
|
|
|
|
|
|
|
|
#define NEED_IP(t, x) \
|
|
|
|
do { \
|
|
|
|
if (!HAVE_IP(t, x)) \
|
|
|
|
goto input_overrun; \
|
|
|
|
} while (0)
|
|
|
|
|
|
|
|
#define NEED_OP(t, x) \
|
|
|
|
do { \
|
|
|
|
if (!HAVE_OP(t, x)) \
|
|
|
|
goto output_overrun; \
|
|
|
|
} while (0)
|
|
|
|
|
|
|
|
#define TEST_LB(m_pos) \
|
|
|
|
do { \
|
|
|
|
if ((m_pos) < out) \
|
|
|
|
goto lookbehind_overrun; \
|
|
|
|
} while (0)
|
2007-07-11 08:22:24 +08:00
|
|
|
|
|
|
|
int lzo1x_decompress_safe(const unsigned char *in, size_t in_len,
|
2012-08-13 23:25:44 +08:00
|
|
|
unsigned char *out, size_t *out_len)
|
2007-07-11 08:22:24 +08:00
|
|
|
{
|
2012-08-13 23:25:44 +08:00
|
|
|
unsigned char *op;
|
|
|
|
const unsigned char *ip;
|
|
|
|
size_t t, next;
|
|
|
|
size_t state = 0;
|
|
|
|
const unsigned char *m_pos;
|
2007-07-11 08:22:24 +08:00
|
|
|
const unsigned char * const ip_end = in + in_len;
|
|
|
|
unsigned char * const op_end = out + *out_len;
|
|
|
|
|
2012-08-13 23:25:44 +08:00
|
|
|
op = out;
|
|
|
|
ip = in;
|
2007-07-11 08:22:24 +08:00
|
|
|
|
2012-08-13 23:25:44 +08:00
|
|
|
if (unlikely(in_len < 3))
|
|
|
|
goto input_overrun;
|
2007-07-11 08:22:24 +08:00
|
|
|
if (*ip > 17) {
|
|
|
|
t = *ip++ - 17;
|
2012-08-13 23:25:44 +08:00
|
|
|
if (t < 4) {
|
|
|
|
next = t;
|
2007-07-11 08:22:24 +08:00
|
|
|
goto match_next;
|
|
|
|
}
|
2012-08-13 23:25:44 +08:00
|
|
|
goto copy_literal_run;
|
|
|
|
}
|
2007-07-11 08:22:24 +08:00
|
|
|
|
2012-08-13 23:25:44 +08:00
|
|
|
for (;;) {
|
2007-07-11 08:22:24 +08:00
|
|
|
t = *ip++;
|
2012-08-13 23:25:44 +08:00
|
|
|
if (t < 16) {
|
|
|
|
if (likely(state == 0)) {
|
|
|
|
if (unlikely(t == 0)) {
|
|
|
|
while (unlikely(*ip == 0)) {
|
2007-07-11 08:22:24 +08:00
|
|
|
t += 255;
|
|
|
|
ip++;
|
2014-06-21 13:00:53 +08:00
|
|
|
NEED_IP(1, 0);
|
2007-07-11 08:22:24 +08:00
|
|
|
}
|
2012-08-13 23:25:44 +08:00
|
|
|
t += 15 + *ip++;
|
2007-07-11 08:22:24 +08:00
|
|
|
}
|
2012-08-13 23:25:44 +08:00
|
|
|
t += 3;
|
|
|
|
copy_literal_run:
|
|
|
|
#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
|
2014-06-21 13:00:53 +08:00
|
|
|
if (likely(HAVE_IP(t, 15) && HAVE_OP(t, 15))) {
|
2012-08-13 23:25:44 +08:00
|
|
|
const unsigned char *ie = ip + t;
|
|
|
|
unsigned char *oe = op + t;
|
|
|
|
do {
|
|
|
|
COPY8(op, ip);
|
|
|
|
op += 8;
|
|
|
|
ip += 8;
|
|
|
|
COPY8(op, ip);
|
|
|
|
op += 8;
|
|
|
|
ip += 8;
|
|
|
|
} while (ip < ie);
|
|
|
|
ip = ie;
|
|
|
|
op = oe;
|
|
|
|
} else
|
|
|
|
#endif
|
|
|
|
{
|
2014-06-21 13:00:53 +08:00
|
|
|
NEED_OP(t, 0);
|
|
|
|
NEED_IP(t, 3);
|
2012-08-13 23:25:44 +08:00
|
|
|
do {
|
|
|
|
*op++ = *ip++;
|
|
|
|
} while (--t > 0);
|
2007-07-11 08:22:24 +08:00
|
|
|
}
|
2012-08-13 23:25:44 +08:00
|
|
|
state = 4;
|
|
|
|
continue;
|
|
|
|
} else if (state != 4) {
|
|
|
|
next = t & 3;
|
2007-07-11 08:22:24 +08:00
|
|
|
m_pos = op - 1;
|
|
|
|
m_pos -= t >> 2;
|
|
|
|
m_pos -= *ip++ << 2;
|
2012-08-13 23:25:44 +08:00
|
|
|
TEST_LB(m_pos);
|
2014-06-21 13:00:53 +08:00
|
|
|
NEED_OP(2, 0);
|
2012-08-13 23:25:44 +08:00
|
|
|
op[0] = m_pos[0];
|
|
|
|
op[1] = m_pos[1];
|
|
|
|
op += 2;
|
|
|
|
goto match_next;
|
|
|
|
} else {
|
|
|
|
next = t & 3;
|
|
|
|
m_pos = op - (1 + M2_MAX_OFFSET);
|
|
|
|
m_pos -= t >> 2;
|
|
|
|
m_pos -= *ip++ << 2;
|
|
|
|
t = 3;
|
2007-07-11 08:22:24 +08:00
|
|
|
}
|
2012-08-13 23:25:44 +08:00
|
|
|
} else if (t >= 64) {
|
|
|
|
next = t & 3;
|
|
|
|
m_pos = op - 1;
|
|
|
|
m_pos -= (t >> 2) & 7;
|
|
|
|
m_pos -= *ip++ << 3;
|
|
|
|
t = (t >> 5) - 1 + (3 - 1);
|
|
|
|
} else if (t >= 32) {
|
|
|
|
t = (t & 31) + (3 - 1);
|
|
|
|
if (unlikely(t == 2)) {
|
|
|
|
while (unlikely(*ip == 0)) {
|
|
|
|
t += 255;
|
|
|
|
ip++;
|
2014-06-21 13:00:53 +08:00
|
|
|
NEED_IP(1, 0);
|
2012-08-13 23:25:44 +08:00
|
|
|
}
|
|
|
|
t += 31 + *ip++;
|
2014-06-21 13:00:53 +08:00
|
|
|
NEED_IP(2, 0);
|
2012-08-13 23:25:44 +08:00
|
|
|
}
|
|
|
|
m_pos = op - 1;
|
|
|
|
next = get_unaligned_le16(ip);
|
|
|
|
ip += 2;
|
|
|
|
m_pos -= next >> 2;
|
|
|
|
next &= 3;
|
|
|
|
} else {
|
|
|
|
m_pos = op;
|
|
|
|
m_pos -= (t & 8) << 11;
|
|
|
|
t = (t & 7) + (3 - 1);
|
|
|
|
if (unlikely(t == 2)) {
|
|
|
|
while (unlikely(*ip == 0)) {
|
|
|
|
t += 255;
|
|
|
|
ip++;
|
2014-06-21 13:00:53 +08:00
|
|
|
NEED_IP(1, 0);
|
2012-08-13 23:25:44 +08:00
|
|
|
}
|
|
|
|
t += 7 + *ip++;
|
2014-06-21 13:00:53 +08:00
|
|
|
NEED_IP(2, 0);
|
2012-08-13 23:25:44 +08:00
|
|
|
}
|
|
|
|
next = get_unaligned_le16(ip);
|
|
|
|
ip += 2;
|
|
|
|
m_pos -= next >> 2;
|
|
|
|
next &= 3;
|
|
|
|
if (m_pos == op)
|
|
|
|
goto eof_found;
|
|
|
|
m_pos -= 0x4000;
|
|
|
|
}
|
|
|
|
TEST_LB(m_pos);
|
|
|
|
#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
|
|
|
|
if (op - m_pos >= 8) {
|
|
|
|
unsigned char *oe = op + t;
|
2014-06-21 13:00:53 +08:00
|
|
|
if (likely(HAVE_OP(t, 15))) {
|
2007-07-11 08:22:24 +08:00
|
|
|
do {
|
2012-08-13 23:25:44 +08:00
|
|
|
COPY8(op, m_pos);
|
|
|
|
op += 8;
|
|
|
|
m_pos += 8;
|
|
|
|
COPY8(op, m_pos);
|
|
|
|
op += 8;
|
|
|
|
m_pos += 8;
|
|
|
|
} while (op < oe);
|
|
|
|
op = oe;
|
2014-06-21 13:00:53 +08:00
|
|
|
if (HAVE_IP(6, 0)) {
|
2012-08-13 23:25:44 +08:00
|
|
|
state = next;
|
|
|
|
COPY4(op, ip);
|
|
|
|
op += next;
|
|
|
|
ip += next;
|
|
|
|
continue;
|
|
|
|
}
|
2007-07-11 08:22:24 +08:00
|
|
|
} else {
|
2014-06-21 13:00:53 +08:00
|
|
|
NEED_OP(t, 0);
|
2007-07-11 08:22:24 +08:00
|
|
|
do {
|
|
|
|
*op++ = *m_pos++;
|
2012-08-13 23:25:44 +08:00
|
|
|
} while (op < oe);
|
2007-07-11 08:22:24 +08:00
|
|
|
}
|
2012-08-13 23:25:44 +08:00
|
|
|
} else
|
|
|
|
#endif
|
|
|
|
{
|
|
|
|
unsigned char *oe = op + t;
|
2014-06-21 13:00:53 +08:00
|
|
|
NEED_OP(t, 0);
|
2012-08-13 23:25:44 +08:00
|
|
|
op[0] = m_pos[0];
|
|
|
|
op[1] = m_pos[1];
|
|
|
|
op += 2;
|
|
|
|
m_pos += 2;
|
|
|
|
do {
|
|
|
|
*op++ = *m_pos++;
|
|
|
|
} while (op < oe);
|
|
|
|
}
|
2007-07-11 08:22:24 +08:00
|
|
|
match_next:
|
2012-08-13 23:25:44 +08:00
|
|
|
state = next;
|
|
|
|
t = next;
|
|
|
|
#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
|
2014-06-21 13:00:53 +08:00
|
|
|
if (likely(HAVE_IP(6, 0) && HAVE_OP(4, 0))) {
|
2012-08-13 23:25:44 +08:00
|
|
|
COPY4(op, ip);
|
|
|
|
op += t;
|
|
|
|
ip += t;
|
|
|
|
} else
|
|
|
|
#endif
|
|
|
|
{
|
2014-06-21 13:00:53 +08:00
|
|
|
NEED_IP(t, 3);
|
|
|
|
NEED_OP(t, 0);
|
2012-08-13 23:25:44 +08:00
|
|
|
while (t > 0) {
|
2007-07-11 08:22:24 +08:00
|
|
|
*op++ = *ip++;
|
2012-08-13 23:25:44 +08:00
|
|
|
t--;
|
2007-07-11 08:22:24 +08:00
|
|
|
}
|
2012-08-13 23:25:44 +08:00
|
|
|
}
|
2007-07-11 08:22:24 +08:00
|
|
|
}
|
|
|
|
|
|
|
|
eof_found:
|
|
|
|
*out_len = op - out;
|
2012-08-13 23:25:44 +08:00
|
|
|
return (t != 3 ? LZO_E_ERROR :
|
|
|
|
ip == ip_end ? LZO_E_OK :
|
|
|
|
ip < ip_end ? LZO_E_INPUT_NOT_CONSUMED : LZO_E_INPUT_OVERRUN);
|
|
|
|
|
2007-07-11 08:22:24 +08:00
|
|
|
input_overrun:
|
|
|
|
*out_len = op - out;
|
|
|
|
return LZO_E_INPUT_OVERRUN;
|
|
|
|
|
|
|
|
output_overrun:
|
|
|
|
*out_len = op - out;
|
|
|
|
return LZO_E_OUTPUT_OVERRUN;
|
|
|
|
|
|
|
|
lookbehind_overrun:
|
|
|
|
*out_len = op - out;
|
|
|
|
return LZO_E_LOOKBEHIND_OVERRUN;
|
|
|
|
}
|
lib: add support for LZO-compressed kernels
This patch series adds generic support for creating and extracting
LZO-compressed kernel images, as well as support for using such images on
the x86 and ARM architectures, and support for creating and using
LZO-compressed initrd and initramfs images.
Russell King said:
: Testing on a Cortex A9 model:
: - lzo decompressor is 65% of the time gzip takes to decompress a kernel
: - lzo kernel is 9% larger than a gzip kernel
:
: which I'm happy to say confirms your figures when comparing the two.
:
: However, when comparing your new gzip code to the old gzip code:
: - new is 99% of the size of the old code
: - new takes 42% of the time to decompress than the old code
:
: What this means is that for a proper comparison, the results get even better:
: - lzo is 7.5% larger than the old gzip'd kernel image
: - lzo takes 28% of the time that the old gzip code took
:
: So the expense seems definitely worth the effort. The only reason I
: can think of ever using gzip would be if you needed the additional
: compression (eg, because you have limited flash to store the image.)
:
: I would argue that the default for ARM should therefore be LZO.
This patch:
The lzo compressor is worse than gzip at compression, but faster at
extraction. Here are some figures for an ARM board I'm working on:
Uncompressed size: 3.24Mo
gzip 1.61Mo 0.72s
lzo 1.75Mo 0.48s
So for a compression ratio that is still relatively close to gzip, it's
much faster to extract, at least in that case.
This part contains:
- Makefile routine to support lzo compression
- Fixes to the existing lzo compressor so that it can be used in
compressed kernels
- wrapper around the existing lzo1x_decompress, as it only extracts one
block at a time, while we need to extract a whole file here
- config dialog for kernel compression
[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: cleanup]
Signed-off-by: Albin Tonnerre <albin.tonnerre@free-electrons.com>
Tested-by: Wu Zhangjin <wuzhangjin@gmail.com>
Acked-by: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Russell King <rmk@arm.linux.org.uk>
Acked-by: Russell King <rmk@arm.linux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-01-09 06:42:42 +08:00
|
|
|
#ifndef STATIC
|
2007-07-11 08:22:24 +08:00
|
|
|
EXPORT_SYMBOL_GPL(lzo1x_decompress_safe);
|
|
|
|
|
|
|
|
MODULE_LICENSE("GPL");
|
|
|
|
MODULE_DESCRIPTION("LZO1X Decompressor");
|
|
|
|
|
lib: add support for LZO-compressed kernels
This patch series adds generic support for creating and extracting
LZO-compressed kernel images, as well as support for using such images on
the x86 and ARM architectures, and support for creating and using
LZO-compressed initrd and initramfs images.
Russell King said:
: Testing on a Cortex A9 model:
: - lzo decompressor is 65% of the time gzip takes to decompress a kernel
: - lzo kernel is 9% larger than a gzip kernel
:
: which I'm happy to say confirms your figures when comparing the two.
:
: However, when comparing your new gzip code to the old gzip code:
: - new is 99% of the size of the old code
: - new takes 42% of the time to decompress than the old code
:
: What this means is that for a proper comparison, the results get even better:
: - lzo is 7.5% larger than the old gzip'd kernel image
: - lzo takes 28% of the time that the old gzip code took
:
: So the expense seems definitely worth the effort. The only reason I
: can think of ever using gzip would be if you needed the additional
: compression (eg, because you have limited flash to store the image.)
:
: I would argue that the default for ARM should therefore be LZO.
This patch:
The lzo compressor is worse than gzip at compression, but faster at
extraction. Here are some figures for an ARM board I'm working on:
Uncompressed size: 3.24Mo
gzip 1.61Mo 0.72s
lzo 1.75Mo 0.48s
So for a compression ratio that is still relatively close to gzip, it's
much faster to extract, at least in that case.
This part contains:
- Makefile routine to support lzo compression
- Fixes to the existing lzo compressor so that it can be used in
compressed kernels
- wrapper around the existing lzo1x_decompress, as it only extracts one
block at a time, while we need to extract a whole file here
- config dialog for kernel compression
[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: cleanup]
Signed-off-by: Albin Tonnerre <albin.tonnerre@free-electrons.com>
Tested-by: Wu Zhangjin <wuzhangjin@gmail.com>
Acked-by: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Russell King <rmk@arm.linux.org.uk>
Acked-by: Russell King <rmk@arm.linux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-01-09 06:42:42 +08:00
|
|
|
#endif
|