Getting started

Host setup

The below describes building Firedancer from scratch and running it optimized on a stock GCP n2-standard-80 instance with a stock GCP RHEL8.5 image. For reference, this instance is a dual socket 20 physical core Intel Cascade Lake at 2.8 GHz with hyperthreading enabled -> 2 NUMA nodes total, 80 logical cores total).

Setup for other reasonably modern x86_64 architecture hosts (reasonable modern here AVX2 support, this includes most Intel architectures since ~mid-2013 and AMD architectures since ~mid-2015) running reasonable modern Linux-ish distributions is expected to be very similar. Though it is possible to run Firedancer to run on older hosts, it is not supported and the below assumes a reasonably modern host.

While the Firedancer applications are meant to run from a normal user account, tuning a host to run Firedancer optimally requires a some administrative operations (should not be any more than the existing validator). Though it is possible to run Firedancer without any of these tunings, it is not recommended and the below assumes the user has the necessary sudo access.

Log into the host and configure user environment to taste (e.g. install favorite editors / code development environment, etc). This is not specific to Firedancer but note hosts like this have very minimal installs on first login.
Install standard development tools.
```
$ sudo dnf groupinstall development
```
As mentioned above, the minimal installs are missing even basic development tools. The development group includes such things as the stock gcc compiler, build tools like make, version control systems like git, etc. Firedancer likely can use other tool chains / compilers (e.g. clang) but this is not routinely tested currently.
Install additional dependencies. To simplify install and improve auditability, Firedancer tries to have minimal external dependencies and then only use external dependencies that are trivially installable on recent stock Linux distributions. Current packages used include:
- pkg-config
- libbpf v1.1.0
- xdp-tools
Configure the host for high performance by allowing users to lock pages in memory and increase the scheduler priority of performance critical user threads. As superuser (e.g. sudo su -), add the following lines to /etc/security/limits.conf:
```
* - memlock unlimited
* - nice -20
* - rtprio unlimited
```
(The user might only opt to be more restrictiv if desired, e.g. only allow Firedancer users to do this.) Recommend logging out and then logging back in again after making these changes. ulimit -a can be used to tell if the new user limits have taken effect. E.g., as a regular user, the following would indicate that the changes are in effect:
```
$ ulimit -a
... snip ...
scheduling priority             (-e) 40
... snip ...
max locked memory       (kbytes, -l) unlimited
... snip ...
real-time priority              (-r) unlimited
... snip ...
```
Get Firedancer. E.g.:
```
$ git clone https://github.com/firedancer-io/firedancer.git firedancer
```
will make a directory in the current directory called firedancer and copy of the current head-of-tree code base into that directory.
Build Firedancer. E.g. From the directory where firedancer was checked out:
```
make -j
```
This will do a parallel incremental build using all non-isolated cores and should be reasonably quick even when done from scratch (less than a minute). The default machine target will be MACHINE=linux_gcc_x86_64 (details of this machine can be found in config/linux_gcc_x86_64.mk). The build results will be in the relative directory build/linux/gcc/x86_64. make has many powers; run make help for more info. If building on a system with lots of isolated cores, see contrib/make-j.
Reserve host resources for application usage. E.g.:
```
$ sudo build/linux/gcc/x86_64/bin/fd_shmem_cfg \
  alloc 8 gigantic 0                           \
  alloc 8 gigantic 1                           \
  alloc 512 huge 0                             \
  alloc 512 huge 1
```
will reserve 8 1GiB pages on numa node 0, 8 1GiB pages on numa node 1, 512 2MiB pages on numa node 0, and 512 2MiB pages on numa node 1 on the host for application use (assuming the host in fact has enough free contiguous physical DRAM availability). Adjust this as necessary for the number of cores, system DRAM availabiity, application mix, application configurations, etc. fd_shmem_cfg has many powers. Run fd_shmem_cfg help for more info.
Create an appropriately permissioned sandbox for managing shared memory data structures. E.g.:
```
$ sudo build/linux/gcc/x86_64/bin/fd_shmem_cfg init 0700 [USER] ""
```
where [USER] is the user that will run Firedancer applications. Multiple sandboxes with different permissions, users, groups can / coexist simultaneously (the "" will be use default group of [USER]).

Running

TODO

dboures/firedancer

Getting started

Host setup

Running