# Sampling Profiler

The sampling profiler is a single process profiler to inspect runtime of time consuming processes. This is especially useful for doing performance analysis and optimization.

Please checkout the full documentation at: https://hexdocs.pm/profiler/Profiler.html

Example output for profiling the [Diode Blockchain Server](https://github.com/diodechain/diode_server_ex):
```
iex(2)> Profiler.profile(Chain.Worker)
 100% {:proc_lib, :init_p_do_apply, 3, [file: 'proc_lib.erl', line: 249]}
    100% {:gen_server, :handle_msg, 6, [file: 'gen_server.erl', line: 711]}
       100% {:gen_server, :try_dispatch, 4, [file: 'gen_server.erl', line: 637]}
           26% {Chain.Worker, :handle_info, 2, [file: 'lib/chain/worker.ex', line: 103]}
              26% {Process, :sleep, 1, [file: 'lib/process.ex', line: 253]}
           74% {Chain.Worker, :handle_info, 2, [file: 'lib/chain/worker.ex', line: 110]}
              74% {Chain.Worker, :do_work, 1, [file: 'lib/chain/worker.ex', line: 122]}
                24% {Chain.Block, :sign, 2, [file: 'lib/chain/block.ex', line: 269]}
                    24% {Chain.Header, :sign, 2, [file: 'lib/chain/header.ex', line: 59]}
                      24% {Chain.Header, :encode_egg, 1, [file: 'lib/chain/header.ex', line: 31]}
                50% {Chain.Block, :sign, 2, [file: 'lib/chain/block.ex', line: 270]}
                    50% {Chain.Header, :update_hash, 1, [file: 'lib/chain/header.ex', line: 54]}
                      50% {Chain.Header, :encode_chicken, 1, [file: 'lib/chain/header.ex', line: 43]}
                          50% {MnesiaMerkleTree, :root_hash, 1, [file: 'lib/mnesiamerkletree.ex', line: 62]}
                            49% {MnesiaMerkleTree, :update_merkle_hash_count, 1, [file: 'lib/mnesiamerkletree.ex', line: 393]}
                                49% {:lists, :zipwith, 3, [file: 'lists.erl', line: 451]}
                                  49% {:lists, :zipwith, 3, [file: 'lists.erl', line: 451]}
                                      13% {MnesiaMerkleTree, :signature, 1, [file: 'lib/mnesiamerkletree.ex', line: 460]}
                                      23% {MnesiaMerkleTree, :signature, 1, [file: 'lib/mnesiamerkletree.ex', line: 461]}
                                        23% {BertExt, :encode!, 1, [file: 'lib/bert.ex', line: 43]}
                                            12% {Enum, :"-map/2-lists^map/1-0-", 2, []}
                                            9% {Enum, :map, 2, [file: 'lib/enum.ex', line: 1395]}
:ok
```

# fprof Sugar

Also the profiler has tooling to profile using the erlang native `fprof` module and will call the external [kcachegrind](https://kcachegrind.github.io/html/Home.html) tool when available for visualization.

MacOS: `brew install qcachegrind`
Ubuntu: `sudo apt install kcachegrind`
Windows: https://sourceforge.net/projects/qcachegrindwin/files/latest/download

```
iex(6)> Profiler.fprof(fn -> ExSha3Tiny.sha3_256(str) end)
```

![kcachegrind preview](https://raw.githubusercontent.com/dominicletz/profiler/master/images/kcachegrind.png)

## Installation

The profiler can be installed by adding `profiler` to your list of dependencies in `mix.exs`:

```elixir
def deps do
  [
    {:profiler, "~> 0.2"}
  ]
end
```