# Install lzbench and measure algorithm performance

## In this learning path

- [Introduction](https://learn.arm.com/learning-paths/servers-and-cloud-computing/snappy/)
- [Install lzbench and measure algorithm performance](https://learn.arm.com/learning-paths/servers-and-cloud-computing/snappy/compression/)
- [Next Steps](https://learn.arm.com/learning-paths/servers-and-cloud-computing/snappy/_next-steps/)

## Detailed Steps
The latest released version of [Snappy](http://google.github.io/snappy/) and [Zstandard](http://facebook.github.io/zstd/) data compression algorithms are supported on the following Linux distributions:

- Amazon Linux 2
- RHEL/CentOS 8
- Ubuntu Versions - 22.04, 20.04, 18.04

The detailed steps below have been tested on `AWS EC2` and `Oracle OCI` Arm-based servers running `Ubuntu 20.04`.

## Install necessary software packages
- GNU gcc and g++ for your Arm Linux distribution using the [GNU compiler install guide](https://learn.arm.com/install-guides/gcc/native/).
- Unzip and make utilities

```
sudo apt install -y unzip make
```

## Install lzbench
[lzbench](https://github.com/inikep/lzbench) is an in-memory benchmark of open-source compression algorithms. Use this benchmark to measure stand-alone performance of the compression algorithms on Arm servers.

This benchmark also contains the source files for the `snappy` and `zstd` compression algorithms among others. They are built as part of the `lzbench` build process.

On your running EC2 instance, run the following command:

```
git clone https://github.com/inikep/lzbench && cd lzbench
make
```

## Download a data set to benchmark the compression algorithms
To benchmark the data compression algorithms, you will need a data set to run the compression and decompression algorithms on. Use the [Silesia corpus](https://sun.aei.polsl.pl//~sdeor/index.php?page=silesia) data set, which is a data set of files that covers the typical data types used nowadays.

Download and unpack the data set:

```
cd ..
wget https://sun.aei.polsl.pl//~sdeor/corpus/silesia.zip
mkdir silesia && cd silesia
unzip ../silesia.zip
cd ../lzbench
```

## Run lzbench with snappy and zstd
To benchmark the stand-alone performance of `snappy` with `lzbench`, using one of the files (`dickens`) from the Silesia corpus data set you installed, run the following command:

```
./lzbench -esnappy ../silesia/dickens
```

The output will look similar to:

```
__output__ lzbench 1.8 (64-bit Linux)  (null)
__output__ Assembled by P.Skibinski
__output__
__output__ Compressor name         Compress. Decompress. Compr. size  Ratio Filename
__output__ memcpy                  16435 MB/s 16275 MB/s    10192446 100.00 ../silesia/dickens
__output__ snappy 2020-07-11         234 MB/s   625 MB/s     6340267  62.21 ../silesia/dickens
__output__ done... (cIters=1 dIters=1 cTime=1.0 dTime=2.0 chunkSize=1706MB cSpeed=0MB)
```

To benchmark the stand-alone performance of `zstd` with `lzbench`, using one of the files (`dickens`) from the Silesia corpus data set you installed, run the following command:

```
./lzbench -ezstd ../silesia/dickens
```

The output will look similar to:

```
__output__ lzbench 1.8 (64-bit Linux)  (null)
__output__ Assembled by P.Skibinski
__output__
__output__ Compressor name         Compress. Decompress. Compr. size  Ratio Filename
__output__ memcpy                  17434 MB/s 16647 MB/s    10192446 100.00 ../silesia/dickens
__output__ zstd 1.5.5 -1             194 MB/s   774 MB/s     4261734  41.81 ../silesia/dickens
__output__ done... (cIters=1 dIters=1 cTime=1.0 dTime=2.0 chunkSize=1706MB cSpeed=0MB)
```

The value passed to `-e` in the command above is the compression algorithm.

For full usage and viewing all the arguments you can pass to `lzbench`, run the command below:

```
./lzbench --help
```

You can repeat with another file.

## View Results
The Compression, Decompression Bandwidth, Latency and Compression ratio for the files is printed at the end of each of these commands.

Below is a table with the results on `AWS EC2 Arm 64-bit C6g` instance, with `Ubuntu 20.04` and `gcc 9.3` running with `snappy`.

| File name            | Compression Bandwidth (MB/s) | Decompression Bandwidth(MB/s) | Compression Latency (us) | Decompression Latency(us) | Compr Size | Ratio (%) |
|----------------------|-------------------------------|-------------------------------|--------------------------|-----------------------------|------------|-----------|
| ../silesia/nci       | 755                           | 1900                          | 44271                    | 17684                       | 6146795    | 18.32     |
| ../silesia/xml       | 555                           | 1462                          | 9609                     | 3659                        | 1308581    | 24.48     |
| ../silesia/samba     | 471                           | 1146                          | 45841                    | 18907                       | 8057361    | 37.29     |
| ../silesia/webster   | 296                           | 729                           | 139904                   | 56786                       | 20211213   | 48.75     |
| ../silesia/reymont   | 290                           | 640                           | 22833                    | 10352                       | 3234968    | 48.81     |
| ../silesia/mozilla    | 388                           | 973                           | 131761                   | 52582                       | 26690826   | 52.11     |
| ../silesia/osdb      | 457                           | 1211                          | 22004                    | 8340                        | 5412825    | 53.67     |
| ../silesia/mr        | 373                           | 787                           | 26649                    | 12658                       | 5440451    | 54.57     |
| ../silesia/dickens   | 244                           | 548                           | 41656                    | 18563                       | 6340267    | 62.21     |
| ../silesia/ooffice    | 292                           | 820                           | 21028                    | 7509                        | 4311901    | 70.09     |
| ./silesia/sao       | 313                           | 829                           | 23175                    | 8715                        | 6469352    | 89.21     |
| ../silesia/x-ray     | 6626                          | 11654                         | 1270                     | 698                         | 8459794    | 99.83     |