par-heic2jpeg.cabal

cabal-version:      3.4
-- The cabal-version field refers to the version of the .cabal specification,
-- and can be different from the cabal-install (the tool) version and the
-- Cabal (the library) version you are using. As such, the Cabal (the library)
-- version used must be equal or greater than the version stated in this field.
-- Starting from the specification version 2.2, the cabal-version field must be
-- the first thing in the cabal file.

-- Initial package description 'y' generated by
-- 'cabal init'. For further documentation, see:
--   http://haskell.org/cabal/users-guide/
--
-- The name of the package.
name:               y

-- The package version.
-- See the Haskell package versioning policy (PVP) for standards
-- guiding when and how versions should be incremented.
-- https://pvp.haskell.org
-- PVP summary:     +-+------- breaking API changes
--                  | | +----- non-breaking API additions
--                  | | | +--- code changes with no API change
version:            0.1.0.0

-- A short (one-line) description of the package.
-- synopsis:

-- A longer description of the package.
-- description:

-- The license under which the package is released.
license:            BSD-3-Clause

-- The file containing the license text.
license-file:       LICENSE

-- The package author(s).
author:             Ugo Varetto

-- An email address to which users can send suggestions, bug reports, and patches.
maintainer:         ugovaretto@gmail.com

-- A copyright notice.
-- copyright:
category:           System
build-type:         Simple

-- Extra doc files to be distributed with the package, such as a CHANGELOG or a README.
extra-doc-files:    CHANGELOG.md

-- Extra source files to be distributed with the package, such as examples, or a tutorial module.
-- extra-source-files:

common warnings
    ghc-options: -Wall

executable y
    -- Import common warning flags.
    import:           warnings

    -- .hs or .lhs file containing the Main module.
    main-is:          heic2jpeg.hs

    -- Modules included in this executable, other than Main.
    -- other-modules:

    -- LANGUAGE extensions used by modules in this package.
    -- other-extensions:

    -- Other library packages from which modules are imported.
    build-depends:    base ^>=4.18.0.0,
                      directory,
                      filepath,
                      process,
                      monad-parallel

    -- Directories containing source files.
    hs-source-dirs:   app

    -- Base language which the package is written in.
    default-language: GHC2021

    ghc-options:
        -O3
        -threaded
        -rtsopts
        -with-rtsopts=-s

par-heic2jpeg.hs

-- Parallel conversion of HEIC to JPEG
import System.Directory
import System.FilePath
import Control.Monad
import System.Process
import Data.Char
import System.Environment
import qualified Control.Monad.Parallel as P

main :: IO ()
main = do
        args <- getArgs
        let dir = head args
        c <- listDirectory dir
        f <- filterM (\x -> return (map toLower (snd(splitExtension (dir ++ "/" ++ x))) == ".heic")) c
        _ <- P.mapM (\y -> let x  = dir ++ "/" ++ y 
                           in callProcess "convert" [x, (dropExtension x) ++ ".jpg"]) f
        return ()

report.txt

Converting 27 images from HEIC to JPEG using imagemagick's convert.
-------------------------------------------------------------------

* Serial (Control.Monad.mapM)

         638,360 bytes allocated in the heap
         563,056 bytes copied during GC
          59,256 bytes maximum residency (28 sample(s))
          29,168 bytes maximum slop
               6 MiB total memory in use (0 MiB lost due to fragmentation)

                                     Tot time (elapsed)  Avg pause  Max pause
  Gen  0         0 colls,     0 par    0.000s   0.000s     0.0000s    0.0000s
  Gen  1        28 colls,     0 par    0.013s   0.013s     0.0005s    0.0008s

  TASKS: 4 (1 bound, 3 peak workers (3 total), using -N1)

  SPARKS: 0 (0 converted, 0 overflowed, 0 dud, 0 GC'd, 0 fizzled)

  INIT    time    0.001s  (  0.002s elapsed)
  MUT     time    0.029s  ( 54.509s elapsed)
  GC      time    0.013s  (  0.013s elapsed)
  EXIT    time    0.000s  (  0.007s elapsed)
  Total   time    0.044s  ( 54.530s elapsed)

  Alloc rate    21,872,924 bytes per MUT second

  Productivity  66.8% of total user, 100.0% of total elapsed

-----------------
real    0m54.793s
-----------------


user    1m2.535s
sys     0m11.057s

* Parallel (Control.Monad.Parallel.mapM)

       1,474,456 bytes allocated in the heap
          92,680 bytes copied during GC
         946,880 bytes maximum residency (3 sample(s))
          29,216 bytes maximum slop
               7 MiB total memory in use (0 MiB lost due to fragmentation)

                                     Tot time (elapsed)  Avg pause  Max pause
  Gen  0         0 colls,     0 par    0.000s   0.000s     0.0000s    0.0000s
  Gen  1         3 colls,     0 par    0.009s   0.045s     0.0151s    0.0439s

  TASKS: 30 (1 bound, 29 peak workers (29 total), using -N1)

  SPARKS: 0 (0 converted, 0 overflowed, 0 dud, 0 GC'd, 0 fizzled)

  INIT    time    0.000s  (  0.000s elapsed)
  MUT     time    0.030s  ( 12.520s elapsed)
  GC      time    0.009s  (  0.045s elapsed)
  EXIT    time    0.004s  (  0.004s elapsed)
  Total   time    0.044s  ( 12.570s elapsed)

  Alloc rate    48,486,720 bytes per MUT second

  Productivity  69.8% of total user, 99.6% of total elapsed

-----------------
real    0m12.608s
-----------------


user    4m19.597s
sys     0m18.936s