bzip2: expose tuning knob for faster/smaller code

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2018-02-07 01:33:25 +01:00
parent 2b7515722b
commit 4cae044b43
5 changed files with 41 additions and 20 deletions

View File

@ -19,6 +19,23 @@
//config: Unless you have a specific application which requires bzip2, you
//config: should probably say N here.
//config:
//config:config BZIP2_SMALL
//config: int "Trade bytes for speed (0:fast, 9:small)"
//config: default 8 # all "fast or small" options default to small
//config: range 0 9
//config: depends on BZIP2
//config: help
//config: Trade code size versus speed.
//config: Approximate values with gcc-6.3.0 "bzip -9" compressing
//config: linux-4.15.tar were:
//config: value time (sec) code size (386)
//config: 9 (smallest) 70.11 7687
//config: 8 67.93 8091
//config: 7 67.88 8405
//config: 6 67.78 8624
//config: 5 67.05 9427
//config: 4-0 (fastest) 64.14 12083
//config:
//config:config FEATURE_BZIP2_DECOMPRESS
//config: bool "Enable decompression"
//config: default y
@ -48,7 +65,11 @@
#include "libbb.h"
#include "bb_archive.h"
#define CONFIG_BZIP2_FAST 1
#if CONFIG_BZIP2_SMALL >= 4
#define BZIP2_SPEED (9 - CONFIG_BZIP2_SMALL)
#else
#define BZIP2_SPEED 5
#endif
/* Speed test:
* Compiled with gcc 4.2.1, run on Athlon 64 1800 MHz (512K L2 cache).
@ -56,7 +77,7 @@
* (time to compress gcc-4.2.1.tar is 126.4% compared to bbox).
* At SPEED 5 difference is 32.7%.
*
* Test run of all CONFIG_BZIP2_FAST values on a 11Mb text file:
* Test run of all BZIP2_SPEED values on a 11Mb text file:
* Size Time (3 runs)
* 0: 10828 4.145 4.146 4.148
* 1: 11097 3.845 3.860 3.861

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@ -392,7 +392,7 @@ int mainGtU(EState* state,
* but speeds up compression 10% overall
*/
#if CONFIG_BZIP2_FAST >= 1
#if BZIP2_SPEED >= 1
#define TIMES_8(code) \
code; code; code; code; \
@ -506,7 +506,7 @@ void mainSimpleSort(EState* state,
i++;
/* 1.5% overall speedup, +290 bytes */
#if CONFIG_BZIP2_FAST >= 3
#if BZIP2_SPEED >= 3
/*-- copy 2 --*/
if (i > hi) break;
v = ptr[i];
@ -755,7 +755,7 @@ void mainSort(EState* state)
j = block[0] << 8;
i = nblock - 1;
/* 3%, +300 bytes */
#if CONFIG_BZIP2_FAST >= 2
#if BZIP2_SPEED >= 2
for (; i >= 3; i -= 4) {
quadrant[i] = 0;
j = (j >> 8) | (((unsigned)block[i]) << 8);
@ -794,7 +794,7 @@ void mainSort(EState* state)
unsigned s;
s = block[0] << 8;
i = nblock - 1;
#if CONFIG_BZIP2_FAST >= 2
#if BZIP2_SPEED >= 2
for (; i >= 3; i -= 4) {
s = (s >> 8) | (block[i] << 8);
j = ftab[s] - 1;

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@ -188,7 +188,7 @@ typedef struct EState {
/* stack-saving measures: these can be local, but they are too big */
int32_t sendMTFValues__code [BZ_N_GROUPS][BZ_MAX_ALPHA_SIZE];
int32_t sendMTFValues__rfreq[BZ_N_GROUPS][BZ_MAX_ALPHA_SIZE];
#if CONFIG_BZIP2_FAST >= 5
#if BZIP2_SPEED >= 5
/* second dimension: only 3 needed; 4 makes index calculations faster */
uint32_t sendMTFValues__len_pack[BZ_MAX_ALPHA_SIZE][4];
#endif

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@ -32,6 +32,12 @@ in the file LICENSE.
/* #include "bzlib_private.h" */
#if BZIP2_SPEED >= 5
# define ALWAYS_INLINE_5 ALWAYS_INLINE
#else
# define ALWAYS_INLINE_5 /*nothing*/
#endif
/*---------------------------------------------------*/
/*--- Bit stream I/O ---*/
/*---------------------------------------------------*/
@ -60,9 +66,7 @@ void bsFinishWrite(EState* s)
/*---------------------------------------------------*/
static
/* Helps only on level 5, on other levels hurts. ? */
#if CONFIG_BZIP2_FAST >= 5
ALWAYS_INLINE
#endif
ALWAYS_INLINE_5
void bsW(EState* s, int32_t n, uint32_t v)
{
while (s->bsLive >= 8) {
@ -75,9 +79,7 @@ void bsW(EState* s, int32_t n, uint32_t v)
}
/* Same with n == 16: */
static
#if CONFIG_BZIP2_FAST >= 5
ALWAYS_INLINE
#endif
ALWAYS_INLINE_5
void bsW16(EState* s, uint32_t v)
{
while (s->bsLive >= 8) {
@ -103,9 +105,7 @@ void bsW1_1(EState* s)
s->bsLive += 1;
}
static
#if CONFIG_BZIP2_FAST >= 5
ALWAYS_INLINE
#endif
ALWAYS_INLINE_5
void bsW1_0(EState* s)
{
/* need space for only 1 bit, no need for loop freeing > 8 bits */
@ -394,7 +394,7 @@ void sendMTFValues(EState* s)
s->rfreq[t][v] = 0;
}
#if CONFIG_BZIP2_FAST >= 5
#if BZIP2_SPEED >= 5
/*
* Set up an auxiliary length table which is used to fast-track
* the common case (nGroups == 6).
@ -427,7 +427,7 @@ void sendMTFValues(EState* s)
*/
for (t = 0; t < nGroups; t++)
cost[t] = 0;
#if CONFIG_BZIP2_FAST >= 5
#if BZIP2_SPEED >= 5
if (nGroups == 6 && 50 == ge-gs+1) {
/*--- fast track the common case ---*/
register uint32_t cost01, cost23, cost45;
@ -483,7 +483,7 @@ void sendMTFValues(EState* s)
* Increment the symbol frequencies for the selected table.
*/
/* 1% faster compress. +800 bytes */
#if CONFIG_BZIP2_FAST >= 4
#if BZIP2_SPEED >= 4
if (nGroups == 6 && 50 == ge-gs+1) {
/*--- fast track the common case ---*/
#define BZ_ITUR(nn) s->rfreq[bt][mtfv[gs + (nn)]]++

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@ -48,7 +48,7 @@ in the file LICENSE.
/* 90 bytes, 0.3% of overall compress speed */
#if CONFIG_BZIP2_FAST >= 1
#if BZIP2_SPEED >= 1
/* macro works better than inline (gcc 4.2.1) */
#define DOWNHEAP1(heap, weight, Heap) \