emo/busybox
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

bzip2: expose tuning knob for faster/smaller code

Browse Source 
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
Download Patch File Download Diff File Expand all files Collapse all files

25
archival/bzip2.c
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