diff --git a/tests/parallel/tblocking_channel.nim b/tests/parallel/tblocking_channel.nim
index 8b8b49454..6ec0e1588 100644
--- a/tests/parallel/tblocking_channel.nim
+++ b/tests/parallel/tblocking_channel.nim
@@ -25,11 +25,11 @@ proc emitter() =
 
 spawn emitter()
 # At this point emitter should be stuck in `send`
-sleep(100) # Sleep a bit to ensure that it is still stuck
+sleep(50) # Sleep a bit to ensure that it is still stuck
 doAssert(not msgSent)
 
 spawn receiver()
-sleep(100) # Sleep a bit to let receicer consume the messages
+sleep(50) # Sleep a bit to let receicer consume the messages
 doAssert(msgSent) # Sender should be unblocked
 
 doAssert(chan.trySend(4))
diff --git a/tests/parallel/tconvexhull.nim b/tests/parallel/tconvexhull.nim
index 184a131a2..ebadb874d 100644
--- a/tests/parallel/tconvexhull.nim
+++ b/tests/parallel/tconvexhull.nim
@@ -51,12 +51,11 @@ proc convex_hull[T](points: var seq[T], cmp: proc(x, y: T): int {.closure.}) : s
       ul[k] = spawn half[T](points, k == 0)
   result = concat(^ul[0], ^ul[1])
 
-var s = map(toSeq(0..99999), proc(x: int): Point = (float(x div 1000), float(x mod 1000)))
+var s = map(toSeq(0..9999), proc(x: int): Point = (float(x div 100), float(x mod 100)))
 # On some runs, this pool size reduction will set the "shutdown" attribute on the
 # worker thread that executes our spawned task, before we can read the flowvars.
 setMaxPoolSize 2
 
-#echo convex_hull[Point](s, cmpPoint)
-for i in 0..5:
+for i in 0..2:
   doAssert convex_hull[Point](s, cmpPoint) ==
-      @[(0.0, 0.0), (99.0, 0.0), (99.0, 999.0), (0.0, 999.0)]
+      @[(0.0, 0.0), (99.0, 0.0), (99.0, 99.0), (0.0, 99.0)]
diff --git a/tests/parallel/tdeepcopy.nim b/tests/parallel/tdeepcopy.nim
index 84e2edf3f..499ea94d4 100644
--- a/tests/parallel/tdeepcopy.nim
+++ b/tests/parallel/tdeepcopy.nim
@@ -1,18 +1,54 @@
 discard """
-  output: '''13 abc'''
+  output: '''
+13 abc
+called deepCopy for int
+called deepCopy for int
+done999 999
+'''
 """
 
-type
-  PBinaryTree = ref object
-    le, ri: PBinaryTree
-    value: int
+import threadpool
 
+block one:
+  type
+    PBinaryTree = ref object
+      le, ri: PBinaryTree
+      value: int
 
-proc main =
-  var x: PBinaryTree
-  deepCopy(x, PBinaryTree(ri: PBinaryTree(le: PBinaryTree(value: 13))))
-  var y: string
-  deepCopy y, "abc"
-  echo x.ri.le.value, " ", y
+  proc main =
+    var x: PBinaryTree
+    deepCopy(x, PBinaryTree(ri: PBinaryTree(le: PBinaryTree(value: 13))))
+    var y: string
+    deepCopy y, "abc"
+    echo x.ri.le.value, " ", y
 
-main()
+  main()
+
+
+block two:
+  type
+    Bar[T] = object
+      x: T
+
+  proc `=deepCopy`[T](b: ref Bar[T]): ref Bar[T] =
+    result.new
+    result.x = b.x
+    when T is int:
+      echo "called deepCopy for int"
+    else:
+      echo "called deepCopy for something else"
+
+  proc foo(b: ref Bar[int]): int = 999
+
+# test that the disjoint checker deals with 'a = spawn f(); g = spawn f()':
+
+  proc main =
+    var dummy: ref Bar[int]
+    new(dummy)
+    dummy.x = 44
+    #parallel:
+    let f = spawn foo(dummy)
+    let b = spawn foo(dummy)
+    echo "done", ^f, " ", ^b
+
+  main()
diff --git a/tests/parallel/tdeepcopy2.nim b/tests/parallel/tdeepcopy2.nim
index 2ad623ed1..a9caab604 100644
--- a/tests/parallel/tdeepcopy2.nim
+++ b/tests/parallel/tdeepcopy2.nim
@@ -1,7 +1,9 @@
 discard """
-  output: '''called deepCopy for int
+  output: '''
 called deepCopy for int
-done999 999'''
+called deepCopy for int
+done999 999
+'''
 """
 
 import threadpool
diff --git a/tests/parallel/tdisjoint_slice1.nim b/tests/parallel/tdisjoint_slice1.nim
index c1d0e52f8..edcc30ece 100644
--- a/tests/parallel/tdisjoint_slice1.nim
+++ b/tests/parallel/tdisjoint_slice1.nim
@@ -2,20 +2,49 @@ discard """
   outputsub: "EVEN 28"
 """
 
-import threadpool
-
-proc odd(a: int) =  echo "ODD  ", a
-proc even(a: int) = echo "EVEN ", a
-
-proc main() =
-  var a: array[0..30, int]
-  for i in low(a)..high(a): a[i] = i
-  parallel:
-    var i = 0
-    while i <= 29:
-      spawn even(a[i])
-      spawn odd(a[i+1])
-      inc i, 2
-      # is correct here
-
-main()
+import threadpool, locks
+
+block one:
+  proc odd(a: int) =  echo "ODD  ", a
+  proc even(a: int) = echo "EVEN ", a
+
+  proc main() =
+    var a: array[0..30, int]
+    for i in low(a)..high(a): a[i] = i
+    parallel:
+      var i = 0
+      while i <= 29:
+        spawn even(a[i])
+        spawn odd(a[i+1])
+        inc i, 2
+        # is correct here
+
+  main()
+
+
+block two:
+  var echoLock: Lock
+  initLock echoLock
+
+  proc f(a: openArray[int]) =
+    for x in a:
+      withLock echoLock:
+        echo x
+
+  proc f(a: int) =
+    withLock echoLock:
+      echo a
+
+  proc main() =
+    var a: array[0..9, int] = [0,1,2,3,4,5,6,7,8,9]
+    parallel:
+      spawn f(a[0..2])
+      #spawn f(a[16..30])
+      var i = 3
+      while i <= 8:
+        spawn f(a[i])
+        spawn f(a[i+1])
+        inc i, 2
+        # is correct here
+
+  main()
diff --git a/tests/parallel/tdisjoint_slice2.nim b/tests/parallel/tdisjoint_slice2.nim
deleted file mode 100644
index 25cb2362f..000000000
--- a/tests/parallel/tdisjoint_slice2.nim
+++ /dev/null
@@ -1,40 +0,0 @@
-discard """
-  output: '''0
-1
-2
-3
-4
-5
-6
-7
-8'''
-  sortoutput: true
-"""
-
-import threadpool, locks
-
-var echoLock: Lock
-initLock echoLock
-
-proc f(a: openArray[int]) =
-  for x in a:
-    withLock echoLock:
-      echo x
-
-proc f(a: int) =
-  withLock echoLock:
-    echo a
-
-proc main() =
-  var a: array[0..9, int] = [0,1,2,3,4,5,6,7,8,9]
-  parallel:
-    spawn f(a[0..2])
-    #spawn f(a[16..30])
-    var i = 3
-    while i <= 8:
-      spawn f(a[i])
-      spawn f(a[i+1])
-      inc i, 2
-      # is correct here
-
-main()
diff --git a/tests/parallel/tmissing_deepcopy.nim b/tests/parallel/tmissing_deepcopy.nim
index 94e027b60..7803439fa 100644
--- a/tests/parallel/tmissing_deepcopy.nim
+++ b/tests/parallel/tmissing_deepcopy.nim
@@ -26,10 +26,10 @@ proc greet(p:Person) =
     " friend:", p.friend.name, "(", cast[int](addr p.friend.name),") }"
 
 proc setup =
-  for i in 0 ..< 20:
+  for i in 0 ..< 10:
     people.add newPerson("Person" & $(i + 1))
-  for i in 0 ..< 20:
-    people[i].friend = people[19-i]
+  for i in 0 ..< 10:
+    people[i].friend = people[9-i]
 
 proc update =
   parallel:
diff --git a/tests/parallel/tsendtwice.nim b/tests/parallel/tsendtwice.nim
index 0b3ce15a5..03b7fda47 100644
--- a/tests/parallel/tsendtwice.nim
+++ b/tests/parallel/tsendtwice.nim
@@ -17,9 +17,9 @@ import tables
 type
   Base* = ref object of RootObj
     someSeq: seq[int]
-    baseData: array[400000, byte]
+    baseData: array[40000, byte]
   Derived* = ref object of Base
-    data: array[400000, byte]
+    data: array[40000, byte]
 
 type
   ThreadPool = ref object
diff --git a/tests/parallel/twaitany.nim b/tests/parallel/twaitany.nim
index 2be3d432f..b58cadd86 100644
--- a/tests/parallel/twaitany.nim
+++ b/tests/parallel/twaitany.nim
@@ -3,7 +3,7 @@ discard """
 """
 
 # bug #7638
-import threadpool, os, strformat
+import threadpool, os
 
 proc timer(d: int): int =
   #echo fmt"sleeping {d}"
@@ -11,7 +11,7 @@ proc timer(d: int): int =
   #echo fmt"done {d}"
   return d
 
-var durations = [1000, 1500, 2000, 2500, 3000]
+var durations = [1000, 1500, 2000]
 var tasks: seq[FlowVarBase] = @[]
 var results: seq[int] = @[]
 
@@ -25,11 +25,9 @@ while index != -1:
   #echo repr results
   index = blockUntilAny(tasks)
 
-doAssert results.len == 5
+doAssert results.len == 3
 doAssert 1000 in results
 doAssert 1500 in results
 doAssert 2000 in results
-doAssert 2500 in results
-doAssert 3000 in results
 sync()
 echo "true"