From cfbace25d7bb8bbc25ab29e0c308e61a529dfc70 Mon Sep 17 00:00:00 2001 From: "yann.collet.73@gmail.com" Date: Tue, 24 Jul 2012 17:12:23 +0000 Subject: lz4.c : changed a tuning parameter name to MEMORY_USAGE, to better reflect its impact Makefile : default produces native binary, all produce native & 32-bits binaries git-svn-id: https://lz4.googlecode.com/svn/trunk@70 650e7d94-2a16-8b24-b05c-7c0b3f6821cd --- Makefile | 4 +++- lz4.c | 18 +++++++++--------- 2 files changed, 12 insertions(+), 10 deletions(-) diff --git a/Makefile b/Makefile index 5b87bb6..dbefc12 100644 --- a/Makefile +++ b/Makefile @@ -8,7 +8,9 @@ else OUTPUT = LZ4Demo.exe endif -all: lz4demo +default: lz4demo + +all: lz4demo lz4demo32 lz4demo: lz4.c lz4.h lz4hc.c lz4hc.h bench.c lz4demo.c gcc -O3 -I. -std=c99 -Wall -W -Wundef -Wno-implicit-function-declaration lz4hc.c lz4.c bench.c lz4demo.c -o $(OUTPUT) diff --git a/lz4.c b/lz4.c index 06e2829..b2156cb 100644 --- a/lz4.c +++ b/lz4.c @@ -34,12 +34,12 @@ //************************************** // Tuning parameters //************************************** -// COMPRESSIONLEVEL : -// Increasing this value improves compression ratio -// Lowering this value reduces memory usage -// Reduced memory usage typically improves speed, due to cache effect (ex : L1 32KB for Intel, L1 64KB for AMD) -// Memory usage formula : N->2^(N+2) Bytes (examples : 12 -> 16KB ; 17 -> 512KB) -#define COMPRESSIONLEVEL 12 +// MEMORY_USAGE : +// Memory usage formula : N->2^N Bytes (examples : 10 -> 1KB; 12 -> 4KB ; 16 -> 64KB; 20 -> 1MB; etc.) +// Increasing memory usage improves compression ratio +// Reduced memory usage can improve speed, due to cache effect +// Default value is 14, for 16KB, which nicely fits into Intel x86 L1 cache +#define MEMORY_USAGE 14 // NOTCOMPRESSIBLE_CONFIRMATION : // Decreasing this value will make the algorithm skip faster data segments considered "incompressible" @@ -57,8 +57,8 @@ #define LZ4_COMPRESSMIN 0 // BIG_ENDIAN_NATIVE_BUT_INCOMPATIBLE : -// This will provide a boost to performance for big endian cpu, but the resulting compressed stream will be incompatible with little-endian CPU. -// You can set this option to 1 in situations where data will stay within closed environment +// This will provide a small boost to performance for big endian cpu, but the resulting compressed stream will be incompatible with little-endian CPU. +// You can set this option to 1 in situations where data will remain within closed environment // This option is useless on Little_Endian CPU (such as x86) //#define BIG_ENDIAN_NATIVE_BUT_INCOMPATIBLE 1 @@ -181,7 +181,7 @@ typedef struct _U64_S { U64 v; } U64_S; //************************************** #define MINMATCH 4 -#define HASH_LOG COMPRESSIONLEVEL +#define HASH_LOG (MEMORY_USAGE-2) #define HASHTABLESIZE (1 << HASH_LOG) #define HASH_MASK (HASHTABLESIZE - 1) -- cgit v0.12