dscheck 0.5.0 · OCaml Package

type !'a t

An atomic (mutable) reference to a value of type 'a.

val make : 'a -> 'a t

Create an atomic reference.

val make_contended : 'a -> 'a t

Create an atomic reference that is alone on a cache line. It occupies 4-16x the memory of one allocated with make v.

The primary purpose is to prevent false-sharing and the resulting performance degradation. When a CPU performs an atomic operation, it temporarily takes ownership of an entire cache line that contains the atomic reference. If multiple atomic references share the same cache line, modifying these disjoint memory regions simultaneously becomes impossible, which can create a bottleneck. Hence, as a general guideline, if an atomic reference is experiencing contention, assigning it its own cache line may enhance performance.

val get : 'a t -> 'a

Get the current value of the atomic reference.

val set : 'a t -> 'a -> unit

Set a new value for the atomic reference.

val exchange : 'a t -> 'a -> 'a

Set a new value for the atomic reference, and return the current value.

val compare_and_set : 'a t -> 'a -> 'a -> bool

compare_and_set r seen v sets the new value of r to v only if its current value is physically equal to seen -- the comparison and the set occur atomically. Returns true if the comparison succeeded (so the set happened) and false otherwise.

val fetch_and_add : int t -> int -> int

fetch_and_add r n atomically increments the value of r by n, and returns the current value (before the increment).

val incr : int t -> unit

incr r atomically increments the value of r by 1.

val decr : int t -> unit

decr r atomically decrements the value of r by 1.

val trace : 
  ?impl:[ `Random of int | `Dpor | `Dpor_source ] ->
  ?interleavings:out_channel ->
  ?record_traces:bool ->
  (unit -> unit) ->
  unit

trace ?interleavings ?record_traces f starts the simulation trace.

impl lets user choose the underlying exploration algorithm.

If interleavings output channel is provided, DSCheck will continously print the visited interleavings there.

record_traces enables Trace_tracker, which is typically used for testing DSCheck itself.

val spawn : (unit -> unit) -> unit

spawn f as a new 'thread'

val check : (unit -> bool) -> unit

if f returns false then an assertion has failed

val final : (unit -> unit) -> unit

run f after all processes complete

val every : (unit -> unit) -> unit

run f between every possible interleaving

package dscheck