Stashing: Sadly, we might never know the perf of this channel, back t…

…o the drawing board - nim-lang/Nim#12695

weave/datatypes/context_global.nim

@@ -7,6 +7,7 @@
 
 import
   ../channels/channels_mpsc_bounded_lock,
+  ../channels/channels_mpsc_unbounded,
   ../channels/channels_spsc_single_ptr,
   ../memory/persistacks,
   ../config,
@@ -35,7 +36,7 @@ type
     #   would work but then it requires a pointer indirection
     #   per channel
     #   and a known max number of workers
-    thefts*: ptr UncheckedArray[ChannelLegacy[StealRequest]]
+    thefts*: ptr UncheckedArray[ChannelMPSCunbounded[StealRequest]]
     tasks*: ptr UncheckedArray[Persistack[WV_MaxConcurrentStealPerWorker, ChannelSpscSinglePtr[Task]]]
 
   GlobalContext* = object

weave/datatypes/sync_types.nim

@@ -10,7 +10,8 @@ import
   ../config,
   ../channels/channels_spsc_single_ptr,
   ../instrumentation/contracts,
-  ../memory/allocs
+  ../memory/allocs,
+  std/atomics
 
 # Inter-thread synchronization types
 # ----------------------------------------------------------------------------------
@@ -72,7 +73,8 @@ type
   # Padding shouldn't be needed as steal requests are used as value types
   # and deep-copied between threads
   StealRequest* = ptr object
-    thiefAddr*: ptr ChannelSpscSinglePtr[Task]       # Channel for sending tasks back to the thief
+    next*: Atomic[StealRequest]                   # For intrusive lists and queues
+    thiefAddr*: ptr ChannelSpscSinglePtr[Task]    # Channel for sending tasks back to the thief
     thiefID*: WorkerID
     retry*: int32                                 # 0 <= retry <= num_workers
     victims*: SparseSet                           # set of potential victims

weave/scheduler.nim

@@ -10,7 +10,7 @@ import
   ./primitives/barriers,
   ./datatypes/[sync_types, prell_deques, context_thread_local, flowvars, sparsesets],
   ./channels/[channels_mpsc_bounded_lock, channels_spsc_single_ptr, channels_spsc_single_object],
-  ./memory/[persistacks, intrusive_stacks],
+  ./memory/[persistacks, intrusive_stacks, allocs],
   ./contexts, ./config,
   ./victims, ./loop_splitting,
   ./thieves, ./workers,
@@ -28,10 +28,14 @@ proc init*(ctx: var TLContext) =
   ## Initialize the thread-local context of a worker (including the lead worker)
 
   myWorker().deque = newPrellDeque(Task)
-  myThieves().initialize(WV_MaxConcurrentStealPerWorker * workforce())
   myTodoBoxes().initialize()
   myWorker().initialize(maxID = workforce() - 1)
 
+  # The StealRequest MPSC channel requires a dummy node
+  var dummy: StealRequest
+  wv_allocPtr(dummy)
+  myThieves().initialize(dummy)
+
   localCtx.stealCache.initialize()
   for i in 0 ..< localCtx.stealCache.len:
     localCtx.stealCache.access(i).victims.allocate(capacity = workforce())
@@ -148,6 +152,7 @@ proc schedulingLoop() =
 
 proc threadLocalCleanup*() =
   myWorker().deque.delete()
+  myThieves().removeDummy().wv_free()
   myThieves().delete()
 
   for i in 0 ..< WV_MaxConcurrentStealPerWorker:

weave/thieves.nim

@@ -9,7 +9,7 @@ import
   ./datatypes/[sparsesets, sync_types, context_thread_local],
   ./contexts, ./targets,
   ./instrumentation/[contracts, profilers, loggers],
-  ./channels/channels_mpsc_bounded_lock,
+  ./channels/channels_mpsc_unbounded,
   ./memory/persistacks,
   ./config, ./signals