speculation/speculation.cabal

name:           speculation
version:        1.2.0.2
license:        BSD3
license-file:   LICENSE
author:         Edward A. Kmett
maintainer:     Edward A. Kmett <ekmett@gmail.com>
stability:      experimental
homepage:       http://github.com/ekmett/speculation
category:       Concurrency
copyright:      (c) 2010 Edward A. Kmett
build-type:     Custom
cabal-version:  >=1.6
tested-with:    GHC==6.12.1
synopsis:       A framework for safe, programmable, speculative parallelism
description:
 A framework for safe, programmable, speculative parallelism, loosely based on:
 .
 *  Prakash Prabhu, G. Ramalingam, and Kapil Vaswani, \"/Safe Programmable Speculative Parallelism/\",
    In the proceedings of Programming Language Design and Implementation (PLDI) Vol 45, Issue 6 (June 2010) pp 50-61.
    <http://research.microsoft.com/pubs/118795/pldi026-vaswani.pdf>
 .
 This package provides speculative function application and speculative folds. Speculative STM transactions take the place
 of the transactional rollback machinery from the paper.
 .
 For example:
 . 
 @'spec' g f a@ evaluates @f g@ while forcing @a@, if @g == a@ then @f g@ is returned, otherwise @f a@ is evaluated and returned. Furthermore, if the argument has already been evaluated, we skip the @f g@ computation entirely. If a good guess at the value of @a@ is available, this is one way to induce parallelism in an otherwise sequential task. However, if the guess isn\'t available more cheaply than the actual answer, then this saves no work and if the guess is wrong, you risk evaluating the function twice. Under high load, since 'f g' is computed via the spark queue, the speculation will be skipped and you will obtain the same answer as 'f $! a'.
 .
 The best-case timeline looks like:
 .
 > foreground: [----- a -----]
 > foreground:               [-]    (check g == a)
 > spark:         [----- f g -----]
 > overall:    [--- spec g f a ---]
 .
 The worst-case timeline looks like:
 .
 > foreground: [----- a -----]
 > foreground:               [-]               (check g == a)
 > foreground:                 [---- f a ----]
 > spark:         [----- f g -----]
 > overall:    [-------- spec g f a ---------]
 .
 Note that, if @f g@ takes longer than a to compute, in the HEAD release of GHC, @f g@ will be collected and killed during garbage collection.
 .
 > foreground: [----- a -----]
 > foreground:               [-]               (check g == a)
 > foreground:                 [---- f a ----]
 > spark:         [---- f g ----######         (#'s mark when this spark is collectable)
 > overall:    [--------- spec g f a --------]
 . 
 Under high load:
 .
 > foreground: [----- a -----]
 > foreground:               [-]               (check g == a)
 > foreground:                 [---- f a ----]
 > overall:    [-------- spec g f a ---------]
 .
 Compare these to the timeline of @f $! a@:
 .
 > foreground: [----- a -----]
 > foreground:               [---- f a ----]
 > orverall:   [---------- f $! a ---------]
 .
 'specSTM' provides a similar time table for STM actions, but also rolls back side-effects. The one unfortunate operational distinction is that it is forced to compute 'a' in the background thread and therefore degrades slightly less gracefully under load, although we mitigate this effect by only enqueuing if the number of sparks for the current capability is lower than the total number of capabilities, to try to avoid wasting time when all computational resources are in use.

extra-source-files: 
    README.markdown
    CHANGELOG.markdown
    ISSUES.markdown

source-repository head
  type:     git
  location: http://github.com/ekmett/speculation.git
  branch:   master

flag HasNumSparks
  description: RTS provides GHC.Conc.numSparks
  default: True
  manual: False

flag tests
  description: Build the tests
  default:     False

flag benchmarks
  description: Build the benchmarks
  default:     False

flag optimize
  description: Enable optimizations for the library and benchmarks
  default:     True

flag hpc
  description: Use HPC for tests
  default:     True

library
  ghc-options: -Wall
  if flag(optimize)
    ghc-options: -funbox-strict-fields -O2 -fspec-constr -fdicts-cheap
  if flag(HasNumSparks)
    cpp-options: -DHAS_NUM_SPARKS
    build-depends: base >= 4.3 && < 6
  else
    build-depends: base >= 4 && < 4.3

  build-depends:
    ghc-prim >= 0.2 && < 0.4,
    tag-bits >= 0.1 && < 0.2,
    transformers >= 0.2.2.0 && < 0.3,
    stm >= 2.1 && < 2.3

  exposed-modules:
    Data.Speculation
    Data.Speculation.Cont
    Data.Speculation.Morphism
    Data.Speculation.Foldable
    Data.Speculation.Traversable
    Data.Speculation.List
  other-modules:
    Data.Speculation.Internal

executable test-speculation
  main-is: Test.hs
  if !flag(tests)
    buildable: False
  else
    if flag(hpc)
      ghc-options: -fhpc
      x-hpc: true
    ghc-options: -Wall
    if flag(HasNumSparks)
      cpp-options: -DHAS_NUM_SPARKS
      build-depends: base >= 4.3 && < 6
    else
      build-depends: base >= 4 && < 4.3
    build-depends:
      ghc-prim >= 0.2 && < 0.4,
      tag-bits >= 0.1 && < 0.2,
      stm >= 2.1 && < 2.3,
      transformers >= 0.2.2.0 && < 0.3,
      containers >= 0.3.0 && < 0.5,
      test-framework >= 0.2.4 && < 0.3,
      test-framework-quickcheck >= 0.2.4 && < 0.3,
      test-framework-hunit >= 0.2.4 && < 0.3, 
      QuickCheck >= 1.2.0.0 && < 1.3,
      HUnit >= 1.2.2.1 && < 1.3
    other-modules:
      Data.Speculation
      Data.Speculation.Cont
      Data.Speculation.Morphism
      Data.Speculation.Foldable
      Data.Speculation.Traversable
      Data.Speculation.List
      Data.Speculation.Internal

executable benchmark-speculation
  main-is: Benchmark.hs
  if !flag(benchmarks)
    buildable: False
  else
    ghc-options: -Wall -threaded
    if flag(optimize)
      ghc-options: -O2 -fspec-constr -funbox-strict-fields -fdicts-cheap
    if flag(HasNumSparks)
      cpp-options: -DHAS_NUM_SPARKS
      build-depends: base >= 4.3 && < 6
    else
      build-depends: base >= 4 && < 4.3
    build-depends:
      ghc-prim >= 0.2 && < 0.4,
      transformers >= 0.2.2.0 && < 0.3,
      tag-bits >= 0.1 && < 0.2,
      stm >= 2.1 && < 2.3,
      containers >= 0.3.0 && < 0.5,
      criterion >= 0.5 && < 0.6
    other-modules:
      Data.Speculation
      Data.Speculation.Cont
      Data.Speculation.Morphism
      Data.Speculation.Foldable
      Data.Speculation.Traversable
      Data.Speculation.List
      Data.Speculation.Internal