Added option to set global thread number during runtime

src/malebolgia.nim

@@ -16,7 +16,7 @@
     shouldEndAt: Time
     usesTimeout, activeProducer: bool
 
 proc `=destroy`(m: var Master) {.inline.} =
   deinitCond(m.c)
   deinitLock(m.L)
 
@@ -104,7 +104,7 @@
     data: array[FixedChanSize, PoolTask]
 
 var
-  thr: array[ThreadPoolSize-1, Thread[void]] # -1 because the main thread counts too
+  thr: seq[Thread[void]]
   chan: FixedChan
   globalStopToken: Atomic[bool]
   busyThreads: Atomic[int]
@@ -153,10 +153,13 @@
     # but mark it as completed either way!
     taskCompleted item.m[]
 
-proc setup() =
+proc malebolgiaSetup*(numThr: int) =
+  doAssert numThr > 0, "Malebolgia must be initialized with a thread pool size of at least one"
+  doAssert thr.len == 0, "Malebolgia can only be initialized once"
   initCond(chan.dataAvailable)
   initCond(chan.spaceAvailable)
   initLock(chan.L)
+  thr.setLen(numThr - 1) # -1 because the main thread counts too
   for i in 0..high(thr): createThread[void](thr[i], worker)
 
 proc panicStop*() =
@@ -168,7 +171,10 @@
   deinitLock(chan.L)
 
 proc shouldSend(master: var Master): bool {.inline.} =
-  master.activeProducer or busyThreads.load(moRelaxed) < ThreadPoolSize-1
+  {.cast(gcsafe).}:
+    let numThr = thr.len
+  doAssert numThr > 0, "Malebolgia must be initialized first"
+  master.activeProducer or busyThreads.load(moRelaxed) < numThr
 
 template spawnImplRes[T](master: var Master; fn: typed; res: T) =
   if stillHaveTime(master):
@@ -254,6 +260,6 @@
     waitForCompletions(master)
 
 when not defined(maleSkipSetup):
-  setup()
+  malebolgiaSetup(ThreadPoolSize)
 
 include malebolgia / masterhandles

tests/tasymmetric_load.nim

@@ -0,0 +1,27 @@
+import malebolgia
+
+import std/[os, atomics]
+
+malebolgiaSetup(numThr = 20)
+
+var
+  threadpool = createMaster(activeProducer = true)
+  busyThreads: Atomic[int]
+busyThreads.store 0
+
+let mainThreadId = getThreadId()
+
+proc findStartPositionsAndPlay() =
+  atomicInc busyThreads
+  echo "Started. Busy threads: ", busyThreads.load
+
+  sleep(1000)
+  if getThreadId() == mainThreadId:
+    sleep(10_000)
+
+  atomicDec busyThreads
+  echo "Finished. Busy threads: ", busyThreads.load
+
+threadpool.awaitAll:
+  for i in 1 .. 10000:
+    threadpool.spawn findStartPositionsAndPlay()