Solid Ground

Empex, 2017

Transcript

1. Solid ground
   @sasajuric
   aircloak.com
   

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2. pattern matching
   OTP metaprogramming
   mix
   Distillery
   the pipe operator
   Cowboy
   Plug
   Phoenix
   Ecto
   functional programming
   community
   GenStage
   Credo
   ExUnit
   Combine
   Poolboy
   Nerves
   

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4. LFE
   Erlang
   OTP
   BEAM Elixir
   Phoenix
   GenStage
   Ecto
   Plug
   magic source magic beneficiaries
   Cowboy Poolboy
   

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5. long-running system
   many tasks
   soft real-time
   finite time program
   all-or-nothing
   hard real-time
   

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6. scheduler scheduler scheduler scheduler
   BEAM
   CPU CPU CPU CPU
   

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7. frequent context switches
   

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8. t1
   t2
   t3
   t4
   t5
   10 s
   1 ms
   1 ms
   1 ms
   1 ms
   

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9. t1
   BEAM scheduler
   t2 t3 t4 t5
   t1
   

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10. t1
    cooperative scheduler
    t2 t3 t4 t5
    

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11. thread 1 thread n
    long running task long running task
    blocked
    cooperative scheduler
    …
    

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12. thread 1 thread n
    long running task long running task
    BEAM scheduler
    …
    not blocked :-)
    

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13. activities as runtime citizens
    

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14. send(pid, :please_stop)
    

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15. mref = Process.monitor(pid)
    send(pid, :please_stop)
    receive do
    {:DOWN, ^mref, :process, ^pid, _reason} ->
    :ok
    end
    

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16. mref = Process.monitor(pid)
    send(pid, :please_stop)
    receive do
    {:DOWN, ^mref, :process, ^pid, _reason} -> :ok
    after :timer.seconds(5) ->
    Process.exit(pid, :kill)
    receive do
    {:DOWN, ^mref, :process, ^pid, _reason} -> :ok
    end
    end
    

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17. task = Task.async(fn -> ... end)
    case Task.yield(task, :timer.seconds(5)) do
    {:ok, result} -> do_something(result)
    nil -> Task.shutdown(task, :brutal_kill)
    end
    

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18. shared-nothing concurrency
    

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19. Process
    heap
    resources
    

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20. process-owned “stuff” is released
    

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21. supervision tree
    

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22. system
    backend frontend
    chat history
    repo cache endpoint
    

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23. system
    backend
    chat history
    repo
    

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24. supervisor foundations
    frequent context switching
    activities as runtime citizens
    observable process termination
    stoppable processes
    shared-nothing concurrency
    

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25. syntax
    developer friendliness
    ecosystem
    

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26. runtime 

    guarantees
    syntax
    developer friendliness
    ecosystem
    

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27. Scales of Justice image taken from clipartfox.com
    How Erlang does scheduling http://jlouisramblings.blogspot.hr/2013/01/how-erlang-does-scheduling.html
    Erlang scheduler details https://hamidreza-s.github.io/erlang/scheduling/real-time/preemptive/migration/
    2016/02/09/erlang-scheduler-details.html
    The BEAM book https://github.com/happi/theBeamBook
    BEAM wisdoms http://beam-wisdoms.clau.se/en/latest/
    Web based observer https://github.com/shinyscorpion/wobserver
    Recon http://ferd.github.io/recon/
    Erlang performance lab http://www.erlang.pl/
    

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