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name: speculation
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version: 0.8.0
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license: BSD3
license-file: LICENSE
author: Edward A. Kmett
maintainer: Edward A. Kmett <ekmett@gmail.com>
stability: experimental
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homepage: http://github.com/ekmett/speculation
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category: Concurrency
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copyright: (c) 2010 Edward A. Kmett
build-type: Custom
cabal-version: >=1.6
tested-with: GHC==6.12.1
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synopsis: A framework for safe, programmable, speculative parallelism
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description:
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A framework for safe, programmable, speculative parallelism, loosely based on:
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.
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* 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
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of the transactional rollback machinery from the paper.
.
For example:
.
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@'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.
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.
The best-case timeline looks like:
.
> [---- f g ----]
> [----- a -----]
> [-- spec g f a --]
.
The worst-case timeline looks like:
.
> [---- f g ----]
> [----- a -----]
> [---- f a ----]
> [------- spec g f a -----------]
.
Compare these to the timeline of @f $! a@:
.
> [---- a -----]
> [---- f a ----]
.
'specSTM' provides a similar time table for STM actions, but also rolls back side-effects.
.
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/Changes in 0.8.0:/
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.
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* Test suite, code coverage, and benchmark suite added
extra-source-files:
README.markdown
source-repository head
type: git
location: http://github.com/ekmett/speculation.git
branch: master
flag optimize
description: Enable optimizations
default: True
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flag tests
description: Build the tests
default: True
flag benchmarks
description: Build the benchmarks
default: False
flag hpc
description: Use HPC for tests
default: True
flag nolib
description: Don't build the library. Useful for speeding up the modify-build-test cycle.
default: False
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library
ghc-options: -Wall
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if flag(optimize)
ghc-options: -funbox-strict-fields -O2 -fspec-constr -fdicts-cheap
if flag(nolib)
buildable: False
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build-depends:
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base >= 4 && < 6,
parallel >= 2.2 && < 2.3,
stm >= 2.1 && < 2.2
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exposed-modules:
Control.Concurrent.Speculation
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Data.Foldable.Speculation
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executable test-speculation
main-is: Test.hs
if !flag(tests)
buildable: False
else
if flag(hpc)
ghc-options: -fhpc
ghc-options: -Wall
build-depends:
base >= 4 && < 6,
stm >= 2.1 && < 2.2,
containers >= 0.3.0 && < 0.4,
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:
Control.Concurrent.Speculation
Data.Foldable.Speculation
executable benchmark-speculation
main-is: Benchmark.hs
if !flag(benchmarks)
buildable: False
else
ghc-options: -Wall
if flag(optimize)
ghc-options: -O2 -fspec-constr -funbox-strict-fields -fdicts-cheap
build-depends:
base >= 4 && < 6,
stm >= 2.1 && < 2.2,
containers >= 0.3.0 && < 0.4,
criterion >= 0.5 && < 0.6
other-modules:
Control.Concurrent.Speculation
Data.Foldable.Speculation