see: https://github.com/nim-lang/Nim/issues/10617

set_times.nim

import times
import intsets
import tables
import sets

# cardinality for builtin sets is slow.
# nim c -d:release -r t.nim
# vs
# nim c -d:card -d:release -r t.nim

proc aset(): int =
  var n = 0
  var s: set[uint16] = {}
  var o: set[uint16] = {0'u16,1,2,3,4,5,6,7,8,9,10}

  for i in 0..10000:
    for k in 0..24:
      s.incl(k.uint16)

    when defined(card):
      doAssert (s * o).card == 11

    for k in 0..24:
      s.excl(k.uint16)
    when defined(card):
      doAssert s.card == 0
    n += 1
  return n

proc hset(): int =
  var n = 0
  var s = initSet[uint16]()
  var o = initSet[uint16]()
  for i in 0..10: o.incl(i.uint16)

  for i in 0..10000:
    for k in 0..24:
      s.incl(k.uint16)
    when defined(card):
      doAssert (s * o).card == 11

    for k in 0..24:
      s.excl(k.uint16)
    when defined(card):
      doAssert s.card == 0
    n += 1
  return n

proc iset(): int =
  var n = 0
  var s = initIntSet()
  var o = initIntSet()
  for i in 0..10: o.incl(i)

  for i in 0..10000:
    for k in 0..24:
      s.incl(k)
    when defined(card):
      doAssert (s * o).card == 11

    for k in 0..24:
      s.excl(k)
    when defined(card):
      doAssert s.card == 0
    n += 1
  return n

var t = cpuTime()
echo hset()
echo cpuTime() - t

t = cpuTime()
echo aset()
echo cpuTime() - t

t = cpuTime()
echo iset()
echo cpuTime() - t