AuroraMiddleware/zstd
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Merge pull request #59 from Cyan4973/dev

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Yann Collet 2015-11-02 03:19:38 +01:00
commit da8557e6dc
6 changed files with 16 additions and 18 deletions
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2
Makefile
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# ################################################################
# Version number
export VERSION := 0.3.0
export VERSION := 0.3.1
PRGDIR = programs
ZSTDDIR = lib

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NEWS
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v0.3.1 :
Small compression ratio improvement
v0.3
HC mode : compression levels 2-26

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README.md
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@ -13,36 +13,31 @@ For a taste of its performance, here are a few benchmark numbers from a number o
|-----------------|-------|--------:|--------:|
| | | MB/s | MB/s |
| **zstd 0.3** |**2.858**|**280**| **670** |
| [zlib 1.2.8] -1 | 2.730 | 70 | 300 |
| [zlib] 1.2.8 -1 | 2.730 | 70 | 300 |
| QuickLZ 1.5.1b6 | 2.237 | 370 | 415 |
| LZO 2.06 | 2.106 | 400 | 580 |
| [LZ4] r131 | 2.101 | 450 | 2100 |
| Snappy 1.1.0 | 2.091 | 330 | 1100 |
| LZF 3.6 | 2.077 | 200 | 560 |
[zlib 1.2.8]:http://www.zlib.net/
[zlib]:http://www.zlib.net/
[LZ4]:http://www.lz4.org/
Zstd can also offer stronger compression ratio at the cost of compression speed, but preserving its decompression speed. In the following test, a few compressors suitable for this scenario are selected (they offer very asymetric performance, useful when compression time has little importance). The test was completed on a Core i7-5600U @ 2.6 GHz, using [benchmark 0.6.1](http://encode.ru/threads/1266-In-memory-benchmark-with-fastest-LZSS-(QuickLZ-Snappy)-compressors?p=45217&viewfull=1#post45217), an open-source benchmark program by inikep.
Zstd can also offer stronger compression ratio at the cost of compression speed. Compression speed is highly configurable, by small increment, to fit different situations. Note however that decompression speed is preserved and remain roughly the same at all settings, a property shared by most LZ compression algorithms, such as [zlib]. The following test is run on a Core i7-3930K CPU @ 4.5GHz, using [lzbench], an open-source in-memory benchmark by inikep.
|Name | Ratio | C.speed | D.speed |
|-----------------|-------|--------:|--------:|
| | | MB/s | MB/s |
| brotli -9 | 3.729 | 4 | 340 |
| **zstd 0.3 -9** |**3.447**|**30** | **640** |
| [zlib 1.2.8] -9 | 3.133 | 10 | 300 |
| LZO 2.06 -999 | 2.790 | 1 | 560 |
| [LZ4] r131 -9 | 2.720 | 25 | 2100 |
[lzbench]:https://github.com/inikep/lzbench
Compression Ratio vs Speed | Decompression Speed
---------------------------|--------------------
![Compression Ratio vs Speed](images/CSpeed.png "Compression Ratio vs Speed") | ![Decompression Speed](images/DSpeed.png "Decompression Speed")
[lzma]:http://www.7-zip.org/
Zstd compression speed is highly configurable, by small increment, to fit different situations. Its memory requirement can also be configured to fit into low-memory hardware configurations, or servers handling multiple connections/contexts in parallel.
Zstd entropy stage is provided by [Huff0 and FSE, from Finite State Entrop library](https://github.com/Cyan4973/FiniteStateEntropy).
Zstd has not yet reached "stable" status. Specifically, it doesn't guarantee yet that its current compressed format will remain stable and supported in future versions. It may still change to adapt further optimizations still being investigated. That being said, the library is now pretty robust, able to withstand hazards situations, including invalid input. The library reliability has been tested using [Fuzz Testing](https://en.wikipedia.org/wiki/Fuzz_testing), with both [internal tools](programs/fuzzer.c) and [external ones](http://lcamtuf.coredump.cx/afl). Therefore, it's now safe to test Zstandard even within production environments.
Its memory requirement can also be configured to fit into low-memory hardware configurations, or servers handling multiple connections/contexts in parallel.
"Stable Format" is projected sometimes early 2016.
Zstd has not yet reached "stable format" status. It doesn't guarantee yet that its current compressed format will remain stable and supported in future versions. During this period, it can still change to adapt new optimizations still being investigated. "Stable Format" is projected sometimes early 2016.
That being said, the library is now fairly robust, able to withstand hazards situations, including invalid inputs. The library reliability has been tested using [Fuzz Testing](https://en.wikipedia.org/wiki/Fuzz_testing), with both [internal tools](programs/fuzzer.c) and [external ones](http://lcamtuf.coredump.cx/afl). Therefore, it seems now safe to test Zstandard even within production environments.
### Branch Policy
The "dev" branch is the one where all contributions will be merged before reaching "master". If you plan to propose a patch, please commit into the "dev" branch or its own feature branch. Direct commit to "master" are not permitted.

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programs/Makefile
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# fullbench32: Same as fullbench, but forced to compile in 32-bits mode
# ##########################################################################
VERSION?= 0.3.0
VERSION?= 0.3.1
DESTDIR?=
PREFIX ?= /usr/local