package picos_std
Sample libraries for Picos
Install
Dune Dependency
Authors
Maintainers
Sources
picos-0.6.0.tbz
sha256=3f5a08199cf65c2dae2f7d68f3877178f1da8eabf5376e15114e5a8958087dfa
sha512=ad24910c47ce614268c4268874bb918da7f8b5f03b3ad706bbf30323635262e94ddab6be24eaebbca706bfa82c0a517d4272b396459e020c185942125c9bdb7b
doc/src/picos_std.awaitable/picos_std_awaitable.ml.html
Source file picos_std_awaitable.ml
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443
module Awaitable = struct type 'a t = { mutable _value : 'a; bits : int } external as_atomic : 'a t -> 'a Atomic.t = "%identity" let make ?padded value = Multicore_magic.copy_as ?padded { _value = value; bits = Random.bits () } let make_contended value = make ~padded:true value let[@inline] get t = Atomic.get (Sys.opaque_identity (as_atomic t)) let[@inline] compare_and_set x b a = Atomic.compare_and_set (as_atomic x) b a let[@inline] exchange t value = Atomic.exchange (as_atomic t) value let[@inline] fetch_and_add t n = Atomic.fetch_and_add (as_atomic t) n let[@inline] set t value = exchange t value |> ignore let[@inline] incr t = fetch_and_add t 1 |> ignore let[@inline] decr t = fetch_and_add t (-1) |> ignore (* *) open Picos type 'a awaitable = 'a t module Packed = struct type t = Packed : 'a awaitable -> t [@@unboxed] let equal = ( == ) let hash (Packed awaitable) = awaitable.bits end module Awaiters = struct type _ tdt = | Zero : [> `Zero ] tdt | One : { awaitable : 'a awaitable; (* Might also want to clear this *) mutable value : 'a; (* This is mutable to avoid space leaks *) trigger : Trigger.t; mutable counter : int; mutable next : min0; } -> [> `One ] tdt | Many : { head : is1; prev : is1; tail : is1 } -> [> `Many ] tdt and min0 = Min0 : [< `Zero | `One ] tdt -> min0 [@@unboxed] and min1 = Min1 : [< `One | `Many ] tdt -> min1 [@@unboxed] and is1 = [ `One ] tdt let[@inline] exec (Many r : [ `Many ] tdt) = if r.prev != r.tail then let (One prev_r) = r.prev in if prev_r.next == Min0 Zero then prev_r.next <- Min0 r.tail let[@inline] snoc t (One tail_r as tail) = match t with | Min1 (One head_r) -> tail_r.counter <- head_r.counter + 1; Many { head = One head_r; prev = One head_r; tail } | Min1 (Many many_r as many) -> exec many; let (One prev_r as prev) = many_r.tail in tail_r.counter <- prev_r.counter + 1; Many { head = many_r.head; prev; tail } external as1 : min0 -> is1 = "%identity" let[@inline] awaitable_of (One r : is1) = Packed.Packed r.awaitable let[@inline] counter_of (One r : is1) = r.counter let[@inline] next_of (One r : is1) ~tail = let next = as1 r.next in let counter = r.counter in if counter_of tail - counter < counter_of next - counter then tail else next let[@inline] set_next_of (One one_r : is1) (next : is1) = one_r.next <- Min0 next let[@inline] generalize (One r : is1) = One r let[@inline] is_signaled (One r : is1) = Trigger.is_signaled r.trigger let[@inline] is_signalable (One r : is1) = get r.awaitable != r.value let[@inline] await (One r : is1) = Trigger.await r.trigger let[@inline] clear (One r : is1) = r.value <- Obj.magic () let[@inline] signal_and_clear (One r : is1) = Trigger.signal r.trigger; r.value <- Obj.magic () let[@inline] last (one : is1) = if is_signaled one then Zero else generalize one let[@inline] signal_last_one (one : is1) = if is_signalable one then begin signal_and_clear one; Zero end else last one let cleanup awaiters ~count = let count = ref count in match awaiters with | Min1 (One r) -> last (One r) | Min1 (Many many_r as many) -> exec many; let tail = many_r.tail in let head = ref tail in let work = ref many_r.head in while !work != tail do if is_signaled !work then begin let next = next_of !work ~tail in let n = !count - 1 in count := n; if n <> 0 then work := next else begin head := next; work := tail end end else begin head := !work; work := tail end done; let head = !head in if head == tail then begin last head end else begin if !count <> 0 then begin let prev = ref head in let work = ref (next_of !prev ~tail) in while !work != tail do let next = next_of !work ~tail in if is_signaled !work then begin set_next_of !prev next; let n = !count - 1 in count := n; if n <> 0 then work := next else work := tail end else begin prev := !work; work := next end done; if !count <> 0 && is_signaled tail then clear tail end; Many { head; prev = tail; tail } end let ( (* test cleanup *) ) = if false then begin [ 1; Int.max_int ] |> List.iter @@ fun count -> for n = 1 to 4 do for bits = 0 to (1 lsl n) - 1 do let make i = let trigger = Trigger.create () in if bits land (1 lsl i) = 0 then Trigger.signal trigger; let awaitable = make 0 and next = Min0 Zero in One { awaitable; value = 1; trigger; counter = 0; next } in let queue = ref (Min1 (make 0)) in for i = 1 to n - 1 do queue := Min1 (snoc !queue (make i)) done; let rec fold zero fn = function | Zero -> zero | One r -> fn zero (One r) | Many { head; tail; _ } as many -> exec many; fn (let head = next_of head ~tail in if head != tail then fold zero fn (Many { head; prev = tail; tail }) else fold zero fn (generalize head)) head in let open struct type t = { total : int; signaled : int; initial : int } end in let stats = fold { total = 0; signaled = 0; initial = 0 } @@ fun { total; signaled; initial } one -> let total = total + 1 and signaled = signaled + Bool.to_int (is_signaled one) and initial = initial + Bool.to_int (not (is_signaled one)) in { total; signaled; initial } in let before = stats (match !queue with | Min1 (One r) -> One r | Min1 (Many r) -> Many r) in let after = stats (cleanup !queue ~count) in assert (after.initial = before.initial); assert (after.signaled <= before.signaled); let last_bit = 1 lsl (n - 1) in let last_kept = bits land last_bit = 0 && 1 <> n && bits land lnot last_bit <> 0 in if count = 1 then begin assert ( after.signaled <= before.signaled - Bool.to_int (0 < before.signaled) + Bool.to_int last_kept) end else begin assert (after.total = after.initial + Bool.to_int last_kept) end done done end let signal awaiters ~count = let count = ref count in match awaiters with | Min1 (One one_r) -> signal_last_one (One one_r) | Min1 (Many many_r as many) -> exec many; let tail = many_r.tail in let head = ref tail in let work = ref many_r.head in while !work != tail do if is_signaled !work then work := next_of !work ~tail else if is_signalable !work then begin signal_and_clear !work; let next = next_of !work ~tail in let n = !count - 1 in count := n; if n <> 0 then work := next else begin head := next; work := tail end end else begin head := !work; work := tail end done; let head = !head in if head == tail then if !count <> 0 then signal_last_one head else last head else begin if !count <> 0 then begin let prev = ref head in let work = ref (next_of !prev ~tail) in while !work != tail do let next = next_of !work ~tail in if is_signaled !work then begin set_next_of !prev next; work := next end else if is_signalable !work then begin signal_and_clear !work; set_next_of !prev next; let n = !count - 1 in count := n; if n <> 0 then work := next else work := tail end else begin prev := !work; work := next end done; if !count <> 0 && is_signalable tail then signal_and_clear tail end; Many { head; prev = tail; tail } end let ( (* test signal *) ) = if false then begin [ 1; Int.max_int ] |> List.iter @@ fun count -> for n = 1 to 4 do for signaled_bits = 0 to (1 lsl n) - 1 do for signalable_bits = 0 to (1 lsl n) - 1 do let make i = let trigger = Trigger.create () in let value = signalable_bits land (1 lsl i) in let awaitable = make 0 and next = Min0 Zero in if signaled_bits land (1 lsl i) = 0 then Trigger.signal trigger; One { awaitable; value; trigger; counter = 0; next } in let queue = ref (Min1 (make 0)) in for i = 1 to n - 1 do queue := Min1 (snoc !queue (make i)) done; let rec fold zero fn = function | Zero -> zero | One r -> fn zero (One r) | Many { head; tail; _ } as many -> exec many; fn (let head = next_of head ~tail in if head != tail then fold zero fn (Many { head; prev = tail; tail }) else fold zero fn (generalize head)) head in let open struct type t = { total : int; signalable : int; signaled : int; initial : int; } end in let stats = fold { total = 0; signalable = 0; signaled = 0; initial = 0 } @@ fun { total; signalable; signaled; initial } one -> let total = total + 1 and signalable = signalable + Bool.to_int ((not (is_signaled one)) && is_signalable one) and signaled = signaled + Bool.to_int (is_signaled one) and initial = initial + Bool.to_int (not (is_signaled one)) in { total; signalable; signaled; initial } in let before = stats (match !queue with | Min1 (One r) -> One r | Min1 (Many r) -> Many r) in let after = stats (signal !queue ~count) in (* The assertions here could be made stricter such that enough signaled awaiters should be removed from the queue. Please make the assertions stricter if you plan to modify the signaling logic! *) if count = 1 then begin assert ( (before.signalable = 0 && after.signalable = 0) || after.signalable + 1 = before.signalable) end else begin assert (after.signalable = 0) end done done done end end module Htbl = Picos_aux_htbl let awaiters = Htbl.create ~hashed_type:(module Packed) () let update t ~signal ~count = try let signal = ref signal in let count = ref count in let backoff = ref Backoff.default in while not (let before = Htbl.find_exn awaiters t in match if !signal then Awaiters.signal before ~count:!count else Awaiters.cleanup before ~count:!count with | Zero -> Htbl.try_compare_and_remove awaiters t before | One r -> let after = Awaiters.Min1 (One r) in before == after || Htbl.try_compare_and_set awaiters t before after | Many r -> let after = Awaiters.Min1 (Many r) in before == after || Htbl.try_compare_and_set awaiters t before after) do (* Even if the hash table update after signal fails, the trigger(s) have been signaled. *) signal := false; (* If a single awaiter and multi awaiter cleanup are attempted in parallel it might be that a multi awaiter cleanup "succeeds" and yet some awaiters are left in the queue. For this reason we perform a multi awaiter cleanup after failure. It might be possible to improve upon this with some more clever approach. *) count := Int.max_int; backoff := Backoff.once !backoff done with Not_found -> () module Awaiter = struct type t = Awaiters.is1 let add_as (type a) (t : a awaitable) trigger value = let one : Awaiters.is1 = One { awaitable = t; value; trigger; counter = 0; next = Min0 Zero } in let backoff = ref Backoff.default in while not (match Htbl.find_exn awaiters (Packed t) with | before -> let many = Awaiters.snoc before one in Htbl.try_compare_and_set awaiters (Packed t) before (Min1 many) | exception Not_found -> Htbl.try_add awaiters (Packed t) (Min1 one)) do backoff := Backoff.once !backoff done; one let add (type a) (t : a awaitable) trigger = let unique_value = Sys.opaque_identity (Obj.magic awaiters : a) in add_as t trigger unique_value let remove one = Awaiters.signal_and_clear one; update (Awaiters.awaitable_of one) ~signal:false ~count:1 end let await t value = let trigger = Trigger.create () in let one = Awaiter.add_as t trigger value in if Awaiters.is_signalable one then Awaiter.remove one else match Awaiters.await one with | None -> () | Some exn_bt -> Awaiters.clear one; update (Awaiters.awaitable_of one) ~signal:true ~count:1; Printexc.raise_with_backtrace (fst exn_bt) (snd exn_bt) let[@inline] broadcast t = update (Packed t) ~signal:true ~count:Int.max_int let[@inline] signal t = update (Packed t) ~signal:true ~count:1 let () = Stdlib.at_exit @@ fun () -> match Htbl.find_random_exn awaiters with | _ -> (* This should not normally happen, but might happen due to the program being forced to exit without proper cleanup. Otherwise this may indicate a bug in the cleanup of awaiters. *) Printf.eprintf "Awaitable leaked\n%!" | exception Not_found -> () end
sectionYPositions = computeSectionYPositions($el), 10)"
x-init="setTimeout(() => sectionYPositions = computeSectionYPositions($el), 10)"
>