speculation/speculation.cabal
2010-07-05 09:53:03 -07:00

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name: speculation
version: 0.9.0.0
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'.
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The best-case timeline looks like:
.
> foreground: [----- a -----]
> foreground: [-] (check g == a)
> spark: [----- f g -----]
> overall: [--- spec g f a ---]
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The worst-case timeline looks like:
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> 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.
extra-source-files:
README.markdown
CHANGELOG.markdown
ISSUES.markdown
source-repository head
type: git
location: http://github.com/ekmett/speculation.git
branch: master
flag lib
description: Build the library. Useful for speeding up the modify-build-test cycle.
default: True
manual: True
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
if !flag(lib)
buildable: False
else
ghc-options: -Wall
if flag(optimize)
ghc-options: -funbox-strict-fields -O2 -fspec-constr -fdicts-cheap
build-depends:
base >= 4 && < 6,
ghc-prim >= 0.2 && < 0.3,
parallel >= 2.2 && < 2.3,
stm >= 2.1 && < 2.2
exposed-modules:
Control.Concurrent.Speculation
Control.Morphism.Speculation
Data.Foldable.Speculation
Data.Traversable.Speculation
Data.List.Speculation
other-modules:
Control.Concurrent.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
build-depends:
base >= 4 && < 6,
ghc-prim >= 0.2 && < 0.3,
parallel >= 2.2 && < 2.3,
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.Internal
Control.Concurrent.Speculation
Control.Morphism.Speculation
Data.Foldable.Speculation
Data.Traversable.Speculation
Data.List.Speculation
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
build-depends:
base >= 4 && < 6,
ghc-prim >= 0.2 && < 0.3,
parallel >= 2.2 && < 2.3,
stm >= 2.1 && < 2.2,
containers >= 0.3.0 && < 0.4,
criterion >= 0.5 && < 0.6
other-modules:
Control.Concurrent.Speculation.Internal
Control.Concurrent.Speculation
Control.Morphism.Speculation
Data.Foldable.Speculation
Data.Traversable.Speculation
Data.List.Speculation