Picos_mux_multififoBasic multi-threaded effects based Picos compatible scheduler for OCaml 5.
This scheduler uses a queue per thread to implement a mostly FIFO scheduler. If a thread runs out of fibers to run, it will try to take a fiber from the queues of other threads. Threads also periodically consider taking fibers from other threads to balance the number of fibers per thread. If threads cannot find work, they will go to sleep. A separate heartbeat thread wakes up threads periodically. All of this means that this scheduler should act relatively fairly and work well for concurrent workloads where fairness matters and that short bursts of parallelism should not cause slowdowns. This scheduler also gives priority to fibers woken up due to being canceled.
đ Due to mostly FIFO scheduling this scheduler performs poorly on CPU bound fine grained parallel workloads.
âšī¸ See Picos_mux_fifo for a single-threaded variation of this scheduler.
âšī¸ This scheduler implementation is mostly meant as an example and for use in testing libraries implemented in Picos.
â ī¸ This scheduler uses Picos_io_select internally. If running multiple threads that each run this scheduler, Picos_io_select.configure must be called by the main thread before creating other threads.
val context :
?heartbeat_delay:float ->
?heartbeat_rounds:int ->
?quota:int ->
?fatal_exn_handler:(exn -> unit) ->
unit ->
tcontext () creates a new context for randomized runners. The context must always be consumed by a call of run ~context ....
The optional heartbeat_delay, with a default of 0.005, and heartbeat_rounds, with a default of 100, specify the delay between heartbeats and the number of heartbeat rounds to perform when all the threads appear busy or there doesn't seem to be enough fibers to redistribute. Note that heartbeat_delay may delay program termination.
The optional quota argument defaults to Int.max_int and determines the number of effects a fiber is allowed to perform before it is forced to yield.
val runner_on_this_thread : t -> unitrunner_on_this_thread context starts a runner on the current thread to run fibers on the context. The runner returns when run ~context ... returns.
val run_fiber : ?context:t -> Picos.Fiber.t -> (Picos.Fiber.t -> unit) -> unitrun_fiber fiber main runs the main program as the specified fiber and returns after main and all of the fibers spawned by main have returned.
val run : ?context:t -> ?forbid:bool -> (unit -> 'a) -> 'arun main is equivalent to calling run_fiber with a freshly created fiber and main wrapped to capture the result of main.
The optional forbid argument defaults to false and determines whether propagation of cancelation is initially allowed.
val run_fiber_on :
?heartbeat_delay:float ->
?heartbeat_rounds:int ->
?quota:int ->
?fatal_exn_handler:(exn -> unit) ->
n_domains:int ->
Picos.Fiber.t ->
(Picos.Fiber.t -> unit) ->
unitrun_fiber_on ~n_domains main spawns n_domains - 1 additional domains and runs the main on the current domain and those additional domains.
val run_on :
?heartbeat_delay:float ->
?heartbeat_rounds:int ->
?quota:int ->
?fatal_exn_handler:(exn -> unit) ->
n_domains:int ->
?forbid:bool ->
(unit -> 'a) ->
'arun_on ~n_domains main is equivalent to calling run_fiber_on with a freshly created fiber and main wrapped to capture the result of main.
The optional forbid argument defaults to false and determines whether propagation of cancelation is initially allowed.