Module Gc.Control

type t = {
mutable minor_heap_size : Core_kernel__.Import.int;

The size (in words) of the minor heap. Changing this parameter will trigger a minor collection.

Default: 262144 words / 1MB (32bit) / 2MB (64bit).

mutable major_heap_increment : Core_kernel__.Import.int;

How much to add to the major heap when increasing it. If this number is less than or equal to 1000, it is a percentage of the current heap size (i.e. setting it to 100 will double the heap size at each increase). If it is more than 1000, it is a fixed number of words that will be added to the heap.

Default: 15%.

mutable space_overhead : Core_kernel__.Import.int;

The major GC speed is computed from this parameter. This is the memory that will be "wasted" because the GC does not immediatly collect unreachable blocks. It is expressed as a percentage of the memory used for live data. The GC will work more (use more CPU time and collect blocks more eagerly) if space_overhead is smaller.

Default: 80.

mutable verbose : Core_kernel__.Import.int;

This value controls the GC messages on standard error output. It is a sum of some of the following flags, to print messages on the corresponding events:

  • 0x001 Start of major GC cycle.
  • 0x002 Minor collection and major GC slice.
  • 0x004 Growing and shrinking of the heap.
  • 0x008 Resizing of stacks and memory manager tables.
  • 0x010 Heap compaction.
  • 0x020 Change of GC parameters.
  • 0x040 Computation of major GC slice size.
  • 0x080 Calling of finalisation functions.
  • 0x100 Bytecode executable search at start-up.
  • 0x200 Computation of compaction triggering condition.

Default: 0.

mutable max_overhead : Core_kernel__.Import.int;

Heap compaction is triggered when the estimated amount of "wasted" memory is more than max_overhead percent of the amount of live data. If max_overhead is set to 0, heap compaction is triggered at the end of each major GC cycle (this setting is intended for testing purposes only). If max_overhead >= 1000000, compaction is never triggered.

Default: 500.

mutable stack_limit : Core_kernel__.Import.int;

The maximum size of the stack (in words). This is only relevant to the byte-code runtime, as the native code runtime uses the operating system's stack.

Default: 1048576 words / 4MB (32bit) / 8MB (64bit).

mutable allocation_policy : Core_kernel__.Import.int;

The policy used for allocating in the heap. Possible values are 0 and 1. 0 is the next-fit policy, which is quite fast but can result in fragmentation. 1 is the first-fit policy, which can be slower in some cases but can be better for programs with fragmentation problems.

Default: 0.

window_size : Core_kernel__.Import.int;

The size of the window used by the major GC for smoothing out variations in its workload. This is an integer between 1 and 50.

Default: 1.

since
4.03.0
}
include Bin_prot.Binable.S with type t := t
type t
include Bin_prot.Binable.S_only_functions with type t := t
type t
val bin_size_t : t Bin_prot.Size.sizer
val bin_write_t : t Bin_prot.Write.writer
val bin_read_t : t Bin_prot.Read.reader
val __bin_read_t__ : (int -> t) Bin_prot.Read.reader

This function only needs implementation if t exposed to be a polymorphic variant. Despite what the type reads, this does *not* produce a function after reading; instead it takes the constructor tag (int) before reading and reads the rest of the variant t afterwards.

val bin_shape_t : Bin_prot.Shape.t
val bin_writer_t : t Bin_prot.Type_class.writer
val bin_reader_t : t Bin_prot.Type_class.reader
val bin_t : t Bin_prot.Type_class.t
include Ppx_sexp_conv_lib.Sexpable.S with type t := t
type t
val t_of_sexp : Sexplib0.Sexp.t -> t
val sexp_of_t : t -> Sexplib0.Sexp.t
val window_size : t -> Core_kernel__.Import.int
val allocation_policy : t -> Core_kernel__.Import.int
val set_allocation_policy : t -> Core_kernel__.Import.int -> Core_kernel__.Import.unit
val stack_limit : t -> Core_kernel__.Import.int
val set_stack_limit : t -> Core_kernel__.Import.int -> Core_kernel__.Import.unit
val max_overhead : t -> Core_kernel__.Import.int
val set_max_overhead : t -> Core_kernel__.Import.int -> Core_kernel__.Import.unit
val verbose : t -> Core_kernel__.Import.int
val set_verbose : t -> Core_kernel__.Import.int -> Core_kernel__.Import.unit
val space_overhead : t -> Core_kernel__.Import.int
val set_space_overhead : t -> Core_kernel__.Import.int -> Core_kernel__.Import.unit
val major_heap_increment : t -> Core_kernel__.Import.int
val set_major_heap_increment : t -> Core_kernel__.Import.int -> Core_kernel__.Import.unit
val minor_heap_size : t -> Core_kernel__.Import.int
val set_minor_heap_size : t -> Core_kernel__.Import.int -> Core_kernel__.Import.unit
module Fields : sig ... end
include Core_kernel.Comparable.S with type t := t
include Core_kernel__.Comparable_intf.S_common
include Base.Comparable.S
include Base__.Comparable_intf.Polymorphic_compare
include Base.Comparisons.Infix
type t
val (>=) : t -> t -> bool
val (<=) : t -> t -> bool
val (=) : t -> t -> bool
val (>) : t -> t -> bool
val (<) : t -> t -> bool
val (<>) : t -> t -> bool
val equal : t -> t -> bool
val compare : t -> t -> int

compare t1 t2 returns 0 if t1 is equal to t2, a negative integer if t1 is less than t2, and a positive integer if t1 is greater than t2.

val min : t -> t -> t
val max : t -> t -> t
val ascending : t -> t -> int

ascending is identical to compare. descending x y = ascending y x. These are intended to be mnemonic when used like List.sort ~compare:ascending and List.sort ~cmp:descending, since they cause the list to be sorted in ascending or descending order, respectively.

val descending : t -> t -> int
val between : t -> low:t -> high:t -> bool

between t ~low ~high means low <= t <= high

val clamp_exn : t -> min:t -> max:t -> t

clamp_exn t ~min ~max returns t', the closest value to t such that between t' ~low:min ~high:max is true.

Raises if not (min <= max).

val clamp : t -> min:t -> max:t -> t Base.Or_error.t
include Base.Comparator.S with type t := t
type t
type comparator_witness
val comparator : (t, comparator_witness) Base.Comparator.comparator
include Base__.Comparable_intf.Validate with type t := t
type t
val validate_lbound : min:t Base.Maybe_bound.t -> t Base.Validate.check
val validate_ubound : max:t Base.Maybe_bound.t -> t Base.Validate.check
val validate_bound : min:t Base.Maybe_bound.t -> max:t Base.Maybe_bound.t -> t Base.Validate.check