Merge branch 'master' of github.com:catid/lhc_rs

This commit is contained in:
Christopher Taylor 2017-05-31 23:21:34 -07:00
commit 6237d3ddaf
2 changed files with 15 additions and 12 deletions

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# Benchmarks:
On my (few year old) laptop:
On my (few year old) laptop using AVX2 instruction set. I'm not being very rigorous here. The point is that it's really fast.
Some example performance measurements:
```
Leopard Encoder(0.256 MB in 100 pieces, 10 losses): Input=4990.25 MB/s, Output=499.025 MB/s
Leopard Decoder(0.256 MB in 100 pieces, 10 losses): Input=1407.37 MB/s, Output=140.737 MB/s
Leopard Encoder(0.256 MB in 100 pieces, 10 losses): Input=5333.33 MB/s, Output=533.333 MB/s
Leopard Decoder(0.256 MB in 100 pieces, 10 losses): Input=1695.36 MB/s, Output=169.536 MB/s
Leopard Encoder(0.256 MB in 100 pieces, 20 losses): Input=3560.5 MB/s, Output=712.1 MB/s
Leopard Decoder(0.256 MB in 100 pieces, 20 losses): Input=632.88 MB/s, Output=126.576 MB/s
Leopard Encoder(0.256 MB in 100 pieces, 20 losses): Input=3878.79 MB/s, Output=775.758 MB/s
Leopard Decoder(0.256 MB in 100 pieces, 20 losses): Input=833.876 MB/s, Output=166.775 MB/s
Leopard Encoder(8.192 MB in 128 pieces, 128 losses): Input=1266.13 MB/s, Output=1266.13 MB/s
Leopard Decoder(8.192 MB in 128 pieces, 128 losses): Input=482.243 MB/s, Output=482.243 MB/s
Leopard Encoder(8.192 MB in 128 pieces, 128 losses): Input=1964.98 MB/s, Output=1964.98 MB/s
Leopard Decoder(8.192 MB in 128 pieces, 128 losses): Input=600.542 MB/s, Output=600.542 MB/s
Leopard Encoder(2.56 MB in 1000 pieces, 200 losses): Input=1942.34 MB/s, Output=388.467 MB/s
Leopard Decoder(2.56 MB in 1000 pieces, 200 losses): Input=367.109 MB/s, Output=73.4219 MB/s
@ -41,6 +41,9 @@ The results are all from libraries I've written over the past few years. They a
```
For 64KB data chunks:
Leopard Encoder(8.192 MB in 128 pieces, 128 losses): Input=1964.98 MB/s, Output=1964.98 MB/s
Leopard Decoder(8.192 MB in 128 pieces, 128 losses): Input=600.542 MB/s, Output=600.542 MB/s
CM256 Encoder: 64000 bytes k = 128 m = 128 : 82194.7 usec, 99.6658 MBps
CM256 Decoder: 64000 bytes k = 128 m = 128 : 78279.5 usec, 104.651 MBps
@ -56,12 +59,12 @@ FEC-AL Decoder(8.192 MB in 128 pieces, 128 losses): Input=121.093 MB/s, Output=1
For 128 data pieces of input and 128 data pieces of redundancy:
+ Fastest to encode: Leopard (1.26 GB/s)
+ Fastest to encode: Leopard (1.96 GB/s)
+ Distant second-place: WH256 (660 MB/s), FEC-AL (515 MB/s)
+ Slowest encoders: Longhair, CM256
+ Fastest to decode: WH256 (830 MB/s)
+ Distant second-place: Leopard (480 MB/s)
+ Distant second-place: Leopard (600 MB/s)
+ Slowest decoders: FEC-AL, CM256, Longhair
There are a lot of variables that affect when each of these libraries should be used.
@ -136,8 +139,8 @@ http://github.com/catid/siamese
##### Leopard-RS *new*: O(K Log M) FFT MDS Reed-Solomon codec
Encodes at 1.2 GB/s, and decodes at 480 MB/s for this case.
12x faster than existing MDS approaches to encode, and almost 5x faster to decode.
Encodes at 2 GB/s, and decodes at 600 MB/s for this case.
20x faster than existing MDS approaches to encode, and 6x faster to decode.
This uses a recent result from 2014 introducing a novel polynomial basis permitting FFT over fast Galois fields.
This is an MDS Reed-Solomon similar to Jerasure, Zfec, ISA-L, etc, but much faster.
It requires SSSE3 or newer Intel instruction sets for this speed. Otherwise it runs much slower.

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#### Benchmarks:
Benchmark results are available here:
[https://raw.githubusercontent.com/catid/leopard/master/Benchmarks.md](https://raw.githubusercontent.com/catid/leopard/master/Benchmarks.md)
[https://github.com/catid/leopard/blob/master/Benchmarks.md](https://github.com/catid/leopard/blob/master/Benchmarks.md)
#### FFT Data Layout: