threadDelay :: Int -> IO ()	Source
Suspends the current thread for a given number of microseconds (GHC only).

There is no guarantee that the thread will be rescheduled promptly when the delay has expired, but the thread will ***never continue to run earlier than specified***.


---

module Main where

import Criterion.Main
import Control.Concurrent

sleep1 = do
  threadDelay 1000000
  return ()

main :: IO ()
main = defaultMain [bench "1 sec delay" $ whnfIO sleep1 ]

---
warming up
estimating clock resolution...
mean is 9.540081 us (80001 iterations)
found 1384 outliers among 79997 samples (1.7%)
  1221 (1.5%) high severe
estimating cost of a clock call...
mean is 193.1040 ns (62 iterations)
found 4 outliers among 62 samples (6.5%)
  1 (1.6%) low severe
  1 (1.6%) low mild
  2 (3.2%) high severe

benchmarking 1 sec delay
collecting 100 samples, 1 iterations each, in estimated 100.1319 s
bootstrapping with 100000 resamples
mean: 1.001000 s, lb 1.000953 s, ub 1.001030 s, ci 0.950
std dev: 192.3861 us, lb 131.5291 us, ub 265.3644 us, ci 0.950
found 14 outliers among 100 samples (14.0%)
  10 (10.0%) low severe
  3 (3.0%) high mild
  1 (1.0%) high severe
variance introduced by outliers: 0.990%
variance is unaffected by outliers