leaky: Robust space leak, and its strictification

[ bsd3, program, testing ] [ Propose Tags ]

Robust space leak, and its strictification, for testing deepseq-bounded and seqaid.

See also the project homepage for more information.

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Dependencies base (>=4.0 && <5.0), deepseq-bounded, deepseq-generics, generics-sop, ghc-prim, random, seqaid, template-haskell [details]
License BSD-3-Clause
Author Andrew Seniuk
Maintainer rasfar@gmail.com
Category Testing
Home page http://www.fremissant.net/leaky
Uploaded by AndrewSeniuk at Fri Dec 19 16:57:31 UTC 2014
Distributions NixOS:
Executables leaky
Downloads 6832 total (212 in the last 30 days)
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Docs not available [build log]
All reported builds failed as of 2016-12-12 [all 7 reports]



Only when True, provide the options to enable the seqaid preprocessor and GHC plugin.


Blanket seqaid harness at subexpressions of all possible types.

Shouldn't need a Cabal flag for this, but it's the same problem of casing over integer values for a macro (in a .cabal file). So this need not be orthogonal to FORCING_STRATEGY, but this way it is ... which is okay, actually. (Can then test interactions with other FS=0..6.)


Finally crumbed and availed myself of -F -pgmF, although only for things which are fairly safe via regex (injecting imports, top-level splices, "deriving instance" statements, LANGUAGE pragmas, etc.). (Later: You can't really do without this anymore, although with FORCING_STRATEGY=4 it is possible.)


Dump periodic stats lines, for FORCING_STRATEGY that need it.


I use them, but it's not default because it makes for much longer initial build, as all the dependencies (except base libs) need first to be installed (into the sandbox).


Temporary for testing... (Later: Sadly this is not so temporary. There is some kind of interference between SOP.TH and Seqaid.TH splices which is still unresolved. So, types needing NFDataP (etc.) instances will need to live in a module which is not being harnessed.)


Enable profiling


The problem with using a growing list is, it itself is a leak (as it were), so it's hard to see you've plugged anything. However, the slowdown of "force" relative to "forcep" will be noticed! Alternative to GROWING is FIXED (is at length 10000 at the moment). Fixed list is infinite if INFINITE set below. (INFINITE has no effect when GROWING set.)


XXX For some reason, memory is being retained when REDUCTION is enabled. (Later: Is this still the case? I see it's been set to True throughout development...).


To show DeepSeq.force (FORCING_STRATEGY=1) at its worst.


Put some weighty strict subtrees in the test data structure, so can showcase forcep's specificity relative to forcen.


Use -f <flag> to enable a flag, or -f -<flag> to disable that flag. More info


Maintainer's Corner

For package maintainers and hackage trustees

Readme for leaky-

[back to package description]

This leaky mini-project provides a Haskell program exhibiting classic
space leak behaviour.  It leaks in GHC 7.8.3 (and lower), even when
compiled -O2.

leaky-min-cppd.hs  - a tiny Haskell program that leaks in GHC 7.8.3 -O2
leaky-min.hs       - like leaky-min-cppd.hs, with some alternatives
leaky.hs           - a similar but elaborated example, with .cabal flags

In addition to the source files, more information can be found
at the http://www.fremissant.net/leaky project homepage,
including discussion links (cafe, reddit, etc.).

There may also be a community-editable version at the
https://www.haskell.org/haskellwiki/Space_Leak wiki page.

Configure and build in place:

 >  cabal get leaky                     # download and unpack leaky
 >  cd leaky-                    # (or whatever version it is)
 >  cabal configure && cabal build      # build in place

Run by supplying a seed for the random number generator:

 >  ./dist/build/leaky/leaky 123

Or you may prefer to build in a sandbox:

 >  cabal get leaky
 >  cd leaky-
 >  cabal sandbox init
 >  cabal install --only-dependencies
 >  cabal install

And to run:

 >  ./.cabal-sandbox/bin/leaky 123

NOTE: If you don't build with Cabal, you will need to
put options from leaky.cabal into your command line.

Anyway, seqaid uses both the Cabal library and
the cabal executable, meaning that only FORCING_STRATEGY
from 0 through 3 (refer to leaky.cabal) can work
wtihout the presence of the leaky.cabal file.

The output is explained at http://www.fremissant.net/leaky/output.html
or in the corresponding local document ./HTML/output.html.

The FORCING_STRATEGY CPP macro currently controls the leak and plug
variants, which are best set by editing the leaky.cabal file,reconfiguring
and rebuilding (or reinstalling in the case of a sandbox).  See the
included file rough-fs-twiddling-guide.txt for more details.

There are also some constants in leaky.hs you may like to adjust.

If you have a version of the compiler that does not leak for
the default variant of leaky, please let me know at rasfar@gmail.com,
on in the haskell-cafe thread


announcing leaky.  Also, any discussion whatsoever is most welcome.

Sept. 20, 2014
Andrew Seniuk
rasfar on #haskell