cavis/build_requirements.md

# BRUTEX CAVIS Build Requirements #

You can build CAVIS on either x86_64 linux or x86_64 windows 
(sometimes referred to as amd64). Support for native GPU (CUDA) or CPU (AVX2/ AVX512) support can be enabled.

Linux on x86_64 is the primary target platform.
CAVIS is written in Java, C, C++ and Kotlin, therefore you will need a Java JDK and
C/C++ compiler.

# Table of contents
1. [Introduction](#introduction)
   2. 
2. [Some paragraph](#paragraph1)
    1. [Sub paragraph](#subparagraph1)
3. [Another paragraph](#paragraph2)

## Build Environment Prerequisites <a id="introduction"></a>
CAVIS uses the [Gradle Build Tool](https://gradle.org) and [CMake](https://cmake.org/) to execute the build. 
A Gradle Wrapper is provided, that will pull the right version of gradle.

### Linux x86_64 Prerequisites

Linux Kernel 5.10 or higher

**Required build tools:**

| Tools    | Version    | Remarks                                          |
|----------|------------|--------------------------------------------------|
| Gradle   | \> 7.2     |                                |
| CMake    | \> 2.24.10 |  |
| GNU Make | 3.82       |                                                  |

| Compiler | Version        | Remarks                                           |
| -------- |----------------|---------------------------------------------------|
| GCC      | 7.3.1 - 10.2.1 | C and C++ compiler                                |
| nvcc     | \> 11.4        | only in case you want to compile for CUDA support |
| javac    | JDK 11         | openjdk-11                                        |

#### Amazon Linux 2 ####
Preparation shell script

```shell
sudo  amazon-linux-extras install java-openjdk11 && \
      sudo yum install --assumeyes git make gcc gcc-c++ openssl-devel java-11-openjdk-devel && \
      wget https://github.com/Kitware/CMake/releases/download/v3.24.2/cmake-3.24.2.tar.gz && \
      tar -xf cmake-3.24.2.tar.gz && cd cmake-3.24.2/ && \
      ./bootstrap && make && sudo make install && cd ..
```

In case you have less than 8GB RAM, a swap file should be created
```shell
sudo dd if=/dev/zero of=/swapfile count=8k bs=1M && sudo chmod 600 /swapfile && \
sudo mkswap /swapfile && sudo swapon /swapfile
```

You can make the swap change permanent (surviving a reboot) by putting it into /etc/fstab file.
```shell
echo '/swapfile none swap sw 0 0' | sudo tee -a /etc/fstab
```

In order to resolve Brutex Network IP6 endpoints, you need to add an additional nameserver
```shell
 echo 'nameserver 8.8.8.8' | sudo tee -a /etc/resolv.conf
```
## Some paragraph <a id="paragraph1"></a>
The first paragraph text

### Sub paragraph <a id="subparagraph1"></a>
This is a sub paragraph, formatted in heading 3 style

## Troubleshooting <a id="paragraph2"></a>
### Gradle process just crashes ###
This is likely an out-of-memory problem, check
```shell
dmesg
```
for
```
oom-kill:constraint=CONSTRAINT_NONE,nodemask=(null),cpuset=/,mems_allowed=0,global_oom,task_memcg=/,task=java,pid=16477,uid=1000
[ 6291.694315] Out of memory: Killed process 16477 (java) total-vm:11373580kB, anon-rss:1373168kB, file-rss:0kB, shmem-rss:0kB, UID:1000 pgtables:11220kB oom_score_adj:0
```
and increase i.e. swapfile size (by adding another one).



sudo apt-get -q update
ret=$?
while [ $ret -ne 0 ];
do
echo Waiting for instance to be ready ...
sleep 20s
sudo apt-get -q update
ret=$?
done

echo Instance is ready.

#Create swap
echo Adding swap file
sudo fallocate -l 16G /swapfile
sudo chmod 600 /swapfile
sudo mkswap /swapfile
sudo swapon /swapfile
echo Swap created.

#echo "deb http://deb.debian.org/debian/ buster main" | sudo tee /etc/apt/sources.list
#echo "deb http://deb.debian.org/debian/ buster main contrib non-free" | sudo tee -a /etc/apt/sources.list


sudo apt-get -q --yes install build-essential default-jdk git ninja-build gnupg software-properties-common snapd make g++-multilib g++ g++-8 gcc gcc-8 libopenblas-base libopenblas-dev
ret=$?
while [ $ret -ne 0 ];
do
echo Waiting for instance to be ready ...
sleep 20s
sudo apt-get -q --yes install build-essential default-jdk git ninja-build gnupg software-properties-common snapd make g++-multilib g++ g++-8 gcc gcc-8 libopenblas-base libopenblas-dev
ret=$?
done
#sudo snap install core
#sudo snap install cmake --classic

wget https://github.com/Kitware/CMake/releases/download/v3.20.4/cmake-3.20.4-linux-x86_64.sh
chmod a+x cmake-3.20.4-linux-x86_64.sh
sudo sh cmake-3.20.4-linux-x86_64.sh --skip-license

echo "supersede domain-name-servers 172.31.0.2, 8.8.8.8" | sudo tee -a /etc/dhcp/dhclient.conf
echo "nameserver 8.8.8.8" | sudo tee -a /etc/resolv.conf 

 # Buildparameter: #

 -P\<xxx>\
 CAVIS_AVX_EXTENSION = {avx2 | avx512}, default is avx2