%%-*- mode: erlang -*-

%% @doc Starts the Erlang runtime system with SMP support
%% enabled. This may fail if no runtime system with SMP support is
%% available. The 'auto' setting starts the Erlang runtime system with
%% SMP support enabled if it is available and more than one logical
%% processor are detected. -smp disable starts a runtime system
%% without SMP support.
%%
%% NOTE: The runtime system with SMP support will not be available on
%% all supported platforms. See also the erlang.schedulers settings.
%%
%% NOTE: Some native extensions (NIFs) require use of the SMP
%% emulator.
%%
%% More information at: http://erlang.org/doc/man/erl.html
{mapping, "erlang.smp", "vm_args.-smp", [
  {default, enable},
  {datatype, {enum, [enable, auto, disable]}},
  hidden
]}.

%% @doc Sets the mapping of warning messages for error_logger.
%% Messages sent to the error logger using one of the warning
%% routines can be mapped either to errors (default), warnings
%% (w - default), or info reports (i).
{mapping, "erlang.W", "vm_args.+W", [
  {default, "w"},
  hidden
]}.

%% @doc Sets the number of scheduler threads to create and scheduler
%% threads to set online when erlang.smp support has been enabled. The
%% maximum for both values is 1024. If the Erlang runtime system is
%% able to determine the amount of logical processors configured and
%% logical processors available, schedulers.total will default to
%% logical processors configured, and schedulers.online will default
%% to logical processors available; otherwise, the default values will
%% be 1. Schedulers may be omitted if schedulers.online is not and
%% vice versa.
%%
%% If schedulers.total or schedulers.online is specified as a negative
%% number, the value is subtracted from the default number of logical
%% processors configured or logical processors available,
%% respectively.
%%
%% Specifying the value 0 for Schedulers or SchedulersOnline resets
%% the number of scheduler threads or scheduler threads online
%% respectively to its default value.
%%
%% This option is ignored if the emulator doesn't have SMP support
%% enabled (see the erlang.smp flag).
%%
%% More information at: http://erlang.org/doc/man/erl.html
%% +S Schedulers:SchedulerOnline
{mapping, "erlang.schedulers.total", "vm_args.+S", [
  {default, undefined},
  {datatype, integer},
  {validators, ["=<1024"]}
]}.

%% @see erlang.schedulers.total
{mapping, "erlang.schedulers.online", "vm_args.+S", [
  {default, undefined},
  {datatype, integer},
  {validators, ["=<1024"]}
]}.

{translation, "vm_args.+S",
 fun(Conf) ->
  Total = cuttlefish:conf_get("erlang.schedulers.total", Conf, undefined),
  Online = cuttlefish:conf_get("erlang.schedulers.online", Conf, undefined),
  case {Total, Online} of
      {undefined, undefined} -> cuttlefish:unset();
      {undefined, O} -> ":" ++ integer_to_list(O);
      {T, undefined} -> integer_to_list(T);
      _ -> integer_to_list(Total) ++ ":" ++ integer_to_list(Online)
  end
 end
}.

{validator, "=<1024", "has a maximum value of 1024",
 fun(X) -> X =< 1024 end}.

%% @doc Enables or disables the kernel poll functionality if the
%% emulator supports it. If the emulator does not support kernel poll,
%% and the K flag is passed to the emulator, a warning is issued at
%% startup.
%%
%% Similar information at: http://erlang.org/doc/man/erl.html
{mapping, "erlang.K", "vm_args.+K", [
  {default, on},
  {datatype, flag},
  hidden
]}.

%%%% Tunables
%% @doc Name of the Erlang node
{mapping, "nodename", "vm_args.-name", [
  {default, "{{node}}"}
]}.

%% @doc Cookie for distributed node communication.  All nodes in the
%% same cluster should use the same cookie or they will not be able to
%% communicate.
{mapping, "distributed_cookie", "vm_args.-setcookie", [
  {default, "erlang"}
]}.

%% @doc Sets the number of threads in async thread pool, valid range
%% is 0-1024. If thread support is available, the default is 64.
%%
%% More information at: http://erlang.org/doc/man/erl.html
{mapping, "erlang.async_threads", "vm_args.+A", [
  {default, 64},
  {datatype, integer},
  {validators, ["range:0-1024"]}
]}.

{validator, "range:0-1024", "must be 0 to 1024",
 fun(X) -> X >= 0 andalso X =< 1024 end}.

%% @doc Suggested stack size, in bytes, for threads in the
%% async-thread pool. Valid range is 16-8192 kilowords. The default
%% suggested stack size is 16 kilowords, i.e, 64 kilobyte on 32-bit
%% architectures. This small default size has been chosen since the
%% amount of async-threads might be quite large. The default size is
%% enough for drivers delivered with Erlang/OTP, but might not be
%% sufficiently large for other dynamically linked in drivers that use
%% the driver_async() functionality. Note that the value passed is
%% only a suggestion, and it might even be ignored on some platforms.
%%
%% More information at: http://erlang.org/doc/man/erl.html
{mapping, "erlang.async_threads.stack_size", "vm_args.+a", [
  {datatype, bytesize},
  {validators, [ "stack-size-divisible", "stack-size-range"]},
  hidden
]}.

{validator, "stack-size-divisible", ("must be divisible by " ++ integer_to_list(erlang:system_info({wordsize,external}))),
 fun(X) -> X rem (erlang:system_info({wordsize, external})) == 0 end}.

{validator, "stack-size-range",
 begin
     WordSize = erlang:system_info({wordsize, external}),
     ("must be in the range of " ++ cuttlefish_bytesize:to_string(16 * 1024 * WordSize)
      ++ " to " ++ cuttlefish_bytesize:to_string(8192 * 1024 * WordSize))
 end,
 fun(X) ->
   Scaled = X div (1024 * erlang:system_info({wordsize, external})),
   Scaled =< 8192 andalso Scaled >= 16
 end}.

{translation, "vm_args.+a",
 fun(Conf) ->
   RawValue = cuttlefish:conf_get("erlang.async_threads.stack_size", Conf),
   RawValue div (1024 * erlang:system_info({wordsize, external}))
 end}.

%% Note: OTP R15 and earlier uses -env ERL_MAX_PORTS, R16+ uses +Q
%% @doc The number of concurrent ports/sockets
%% Valid range is 1024-134217727
{mapping, "erlang.max_ports",
  cuttlefish:otp("R16", "vm_args.+Q", "vm_args.-env ERL_MAX_PORTS"), [
  {default, 262144},
  {datatype, integer},
  {validators, ["range4ports"]}
]}.

{validator, "range4ports", "must be 1024 to 134217727",
 fun(X) -> X >= 1024 andalso X =< 134217727 end}.

%% @doc A non-negative integer which indicates how many times
%% generational garbage collections can be done without forcing a
%% fullsweep collection. In low-memory systems (especially without
%% virtual memory), setting the value to 0 can help to conserve
%% memory.
%%
%% More information at:
%% http://www.erlang.org/doc/man/erlang.html#system_flag-2
{mapping, "erlang.fullsweep_after", "vm_args.-env ERL_FULLSWEEP_AFTER", [
  {default, 0},
  {datatype, integer},
  hidden,
  {validators, ["positive_integer"]}
]}.

{validator, "positive_integer", "must be a positive integer",
  fun(X) -> X >= 0 end}.

%% @doc Set the location of crash dumps
{mapping, "erlang.crash_dump", "vm_args.-env ERL_CRASH_DUMP", [
  {default, "{{crash_dump}}"},
  {datatype, file},
  hidden
]}.

%% Note: OTP R15 and earlier uses -env ERL_MAX_ETS_TABLES,
%% R16+ uses +e
%% @doc Raise the ETS table limit
{mapping, "erlang.max_ets_tables",
  cuttlefish:otp("R16", "vm_args.+e", "vm_args.-env ERL_MAX_ETS_TABLES"), [
  {default, 256000},
  {datatype, integer},
  hidden
]}.

%% @doc Raise the default erlang process limit
{mapping, "erlang.process_limit", "vm_args.+P", [
  {datatype, integer},
  {default, 256000},
  hidden
]}.

%% @doc For nodes with many busy_dist_port events, Basho recommends
%% raising the sender-side network distribution buffer size.
%% 32MB may not be sufficient for some workloads and is a suggested
%% starting point. Erlangers may know this as +zdbbl.
%% The Erlang/OTP default is 1024 (1 megabyte).
%% See: http://www.erlang.org/doc/man/erl.html#%2bzdbbl
{mapping, "erlang.distribution_buffer_size", "vm_args.+zdbbl", [
  {datatype, bytesize},
  {commented, "32MB"},
  hidden,
  {validators, ["zdbbl_range"]}
]}.

{translation, "vm_args.+zdbbl",
 fun(Conf) ->
  ZDBBL = cuttlefish:conf_get("erlang.distribution_buffer_size", Conf, undefined),
  case ZDBBL of
    undefined -> undefined;
    X when is_integer(X) -> cuttlefish_util:ceiling(X / 1024); %% Bytes to Kilobytes;
    _ -> undefined
  end
 end
}.

{validator, "zdbbl_range", "must be between 1KB and 2097151KB",
 fun(ZDBBL) ->
  %% 2097151KB = 2147482624
  ZDBBL >= 1024 andalso ZDBBL =< 2147482624
 end
}.

%% @doc Set scheduler forced wakeup interval. All run queues will be
%% scanned each Interval milliseconds. While there are sleeping
%% schedulers in the system, one scheduler will be woken for each
%% non-empty run queue found. An Interval of zero disables this
%% feature, which also is the default.
%%
%% This feature is a workaround for lengthy executing native code, and
%% native code that do not bump reductions properly.
%%
%% More information: http://www.erlang.org/doc/man/erl.html#+sfwi
{mapping, "erlang.schedulers.force_wakeup_interval", "vm_args.+sfwi", [
  {commented, 500},
  {datatype, integer}
]}.

%% @doc Enable or disable scheduler compaction of load. By default
%% scheduler compaction of load is enabled. When enabled, load
%% balancing will strive for a load distribution which causes as many
%% scheduler threads as possible to be fully loaded (i.e., not run out
%% of work). This is accomplished by migrating load (e.g. runnable
%% processes) into a smaller set of schedulers when schedulers
%% frequently run out of work. When disabled, the frequency with which
%% schedulers run out of work will not be taken into account by the
%% load balancing logic.
%%
%% More information: http://www.erlang.org/doc/man/erl.html#+scl
{mapping, "erlang.schedulers.compaction_of_load", "vm_args.+scl", [
  {commented, "false"},
  {datatype, {enum, [true, false]}}
]}.

%% @doc Enable or disable scheduler utilization balancing of load. By
%% default scheduler utilization balancing is disabled and instead
%% scheduler compaction of load is enabled which will strive for a
%% load distribution which causes as many scheduler threads as
%% possible to be fully loaded (i.e., not run out of work). When
%% scheduler utilization balancing is enabled the system will instead
%% try to balance scheduler utilization between schedulers. That is,
%% strive for equal scheduler utilization on all schedulers.
%%
%% More information: http://www.erlang.org/doc/man/erl.html#+sub
{mapping, "erlang.schedulers.utilization_balancing", "vm_args.+sub", [
  {commented, "true"},
  {datatype, {enum, [true, false]}}
]}.

%% @doc For ease of firewall configuration, the Erlang distribution
%% can be bound to a limited range of TCP ports. If this is set, and
%% erlang.distribution.port_range.maximum is *unset*, only this port
%% will be used. If the minimum is *unset*, no restriction will be
%% made on the port range; instead Erlang will listen on a random
%% high-numbered port.
%%
%% More information: http://www.erlang.org/faq/how_do_i.html#id55090
%% http://www.erlang.org/doc/man/kernel_app.html
{mapping, "erlang.distribution.port_range.minimum", "kernel.inet_dist_listen_min", [
  {commented, 6000},
  {datatype, integer},
  hidden
]}.

%% @see erlang.distribution.port_range.minimum
{mapping, "erlang.distribution.port_range.maximum", "kernel.inet_dist_listen_max", [
  {commented, 7999},
  {datatype, integer},
  hidden
]}.

%% @doc Set the net_kernel's net_ticktime.
%%
%% More information: http://www.erlang.org/doc/man/kernel_app.html#net_ticktime
%% and http://www.erlang.org/doc/man/net_kernel.html#set_net_ticktime-1
{mapping, "erlang.distribution.net_ticktime", "vm_args.-kernel net_ticktime", [
  {commented, 60},
  {datatype, integer},
  hidden
]}.