[GHC] #698: allocaBytes does not actually free the memory after the computation
#698: allocaBytes does not actually free the memory after the computation
---+
Reporter: guest |Owner:
Type: bug | Status: new
Priority: normal |Milestone:
Component: Compiler (FFI) | Version: 6.4.1
Severity: normal | Keywords:
Os: Linux | Difficulty: Unknown
Architecture: x86 |
---+
allocaBytes does not appear to free the memory after the computation has
completed. For example, start ghci and run:
{{{allocaBytes (100*1024*1024) $ \_ - getLine}}}
ghci's virtual memory usage will jump up by 100MB. When you press enter
however, it does not drop back down.
restart ghci and try:
{{{bracket (mallocBytes 100*1024*1024) free $ \_ - getLine}}}
This time when you press enter, the memory usage will drop back down to
its pre mallocBytes usage.
This also happens for compiled programs.
Note: the above test will only alloc virtual memory since nothing is ever
read into the malloc'd memory. The following test program will actually
force the pages to be mapped. It results in the same broken behaviour with
the addition that the resident size of ghci gets stuck high.
{{{
module Main where
import Control.Exception
import Foreign.Marshal.Alloc
import Foreign.Ptr
import Data.Word
import System.IO
import System.Mem
test :: Int - IO ()
test mb =
let size = mb * 1024 * 1024 in
do -- bracket (mallocBytes size) free $ wait size -- this version
works
allocaBytes size $ wait size -- this version does not free the
memory afterwards
performGC
wait :: Int - Ptr Word8 - IO ()
wait size p =
bracket (openBinaryFile /dev/scsi/host0/bus0/target0/lun0/part1
ReadMode) (hClose) (\h - hGetBuf h p size putStrLn waiting...
getLine return ())
main =
do test 150
putStrLn is it free?
getLine
return ()
}}}
--
Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/698
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Re: [Haskell] compares :: Ord a = a - a - Ordering - Ordering
On Wed, Feb 15, 2006 at 01:17:43AM +, Ben Rudiak-Gould wrote:
I just realized that the class Ord should have an additional method:
class Eq a = Ord a where
compares :: a - a - Ordering - Ordering
compares x y d = case compare x y of { EQ - d ; o - o }
...
This would make writing Ord instances much easier:
instance (Ord a, Ord b, Ord c, Ord d) = Ord (a,b,c,d) where
compares (a1,b1,c1,d1) (a2,b2,c2,d2) =
compares a1 a2 . compares b1 b2 . compares c1 c2 . compares d1 d2
This does the same thing:
import Data.Monoid
instance (Ord a, Ord b, Ord c, Ord d) = Ord (a,b,c,d) where
compare (a1,b1,c1,d1) (a2,b2,c2,d2) =
compare a1 a2 `mappend` compare b1 b2 `mappend`
compare c1 c2 `mappend` compare d1 d2
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[Haskell] Datatype-generic programming 2006, registration now open
[Apologies for multiple copies] == Registration for DGP 2006 is now open. Please visit the web site for instructions. Spring School on Datatype-Generic Programming http://www.cs.nott.ac.uk/ssdgp2006/ University of Nottingham, UK 24-27 April 2006 Background and objectives Generic programming is a thriving research area aimed at making programming more effective by making it more general. This school aims to give participants insights into the applications of datatype-generic programming and the current research challenges in the area. This school is a successor to the Summer School and Workshop on Generic Programming, held in Oxford in August 2002 (lecture notes appeared as volume 2793 of LNCS). Technical programme The lectures will be tutorial-style (as opposed to conference-style) and will be accessible to beginning computing science postgraduates. The scientific programme consists of six courses given by renowned specialists, and a student session. The list of courses is the following: * Thorsten Altenkirch (University of Nottingham): (in collaboration with Conor McBride and Peter Morris) Generic programming with dependent types * Jeremy Gibbons (University of Oxford): Design Patterns as Higher-Order Datatype-Generic Programs * Ralf Hinze (Universitat of Bonn): Generic Programming, Now! (in collaboration with Andres Loeh) * Johan Jeuring (Universiteit Utrecht): Comparing Approaches to Generic Programming (in collaboration with Ralf Hinze and Andres Loeh) * Ralf Laemmel (Microsoft) The next 700 traversal approaches * Tim Sheard (Portland State University): Putting the Curry-Howard Isomorphism to work. Copies of the draft lecture notes will be provided to all participants. The purpose of the student session is to give students an opportunity to present their work and get feedback. Registrants are invited to propose short talks (15-20 min). The selection will be based on abstracts of 150-400 words. Social programme A conference dinner will be organised (attendance at which will be charged separately). Co-location The Symposium on Trends in Functional Programming (TFP 2006), and the Conference of the Types Project (TYPES 2006) will be held in Nottingham the week before this spring school. Accommodation Information about accommodation is available at the School's web site. APPSEM This is an APPSEM-affiliated event. APPSEM funds can be used to support participants from APPSEM-affiliated sites. This message has been checked for viruses but the contents of an attachment may still contain software viruses, which could damage your computer system: you are advised to perform your own checks. Email communications with the University of Nottingham may be monitored as permitted by UK legislation. ___ Haskell mailing list Haskell@haskell.org http://www.haskell.org/mailman/listinfo/haskell
[Haskell] Re: compares :: Ord a = a - a - Ordering - Ordering
Ben Rudiak-Gould wrote:
I just realized that the class Ord should have an additional method:
class Eq a = Ord a where
compares :: a - a - Ordering - Ordering
compares x y d = case compare x y of { EQ - d ; o - o }
...
How about:
instance (Ord a, Ord b, Ord c, Ord d) = Ord (a,b,c,d) where
compare (a1,b1,c1,d1) (a2,b2,c2,d2) =
compare ((a1,b1,c1),d1) ((a2,b2,c2),d2)
or another tuple nesting)
Christian
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Re: [Haskell] Re: compares :: Ord a = a - a - Ordering - Ordering
Christian Maeder wrote:
Ben Rudiak-Gould wrote:
I just realized that the class Ord should have an additional method:
class Eq a = Ord a where
compares :: a - a - Ordering - Ordering
compares x y d = case compare x y of { EQ - d ; o - o }
...
How about:
instance (Ord a, Ord b, Ord c, Ord d) = Ord (a,b,c,d) where
compare (a1,b1,c1,d1) (a2,b2,c2,d2) =
compare ((a1,b1,c1),d1) ((a2,b2,c2),d2)
or another tuple nesting)
Christian
That works, but...
Constructing the new tuples is usually more heap allocation, and these short
lived data items can make the garbage collection load higher.
The `mappend` method avoids this pitfall.
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[Haskell] Haskell Workshop 2006 Call for papers
Apologies for multiple copies; feel free to distribute further. Cheers, Andres ACM SIGPLAN 2006 Haskell Workshop Call for Papers Portland, Oregon 17 September, 2006 The Haskell Workshop 2006 will be part of the 2006 International Conference on Functional Programming (ICFP) as an associated, ACM SIGPLAN sponsored workshop. Previous Haskell Workshops have been held in La Jolla (1995), Amsterdam (1997), Paris (1999), Montreal (2000), Firenze (2001), Pittsburgh (2002), Uppsala (2003), Snowbird (2004), and Tallinn (2005). Topics The purpose of the Haskell Workshop is to discuss experience with Haskell, and possible future developments for the language. The scope of the workshop includes all aspects of the design, semantics, theory, application, implementation, and teaching of Haskell. Topics of interest include, but are not limited to, the following: * Language Design, with a focus on possible extensions and modifications of Haskell as well as critical discussions of the status quo; * Theory, in the form of a formal treatment of the semantics of the present language or future extensions, type systems, and foundations for program analysis and transformation; * Implementations, including program analysis and transformation, static and dynamic compilation for sequential, parallel, and distributed architectures, memory management as well as foreign function and component interfaces; * Tools, in the form of profilers, tracers, debuggers, pre-processors, and so forth; * Applications, Practice, and Experience with Haskell for scientific and symbolic computing, database, multimedia and Web applications, and so forth as well as general experience with Haskell in education and industry; * Functional Pearls being elegant, instructive examples of using Haskell. Papers in the latter two categories need not necessarily report original research results; they may instead, for example, report practical experience that will be useful to others, re-usable programming idioms, or elegant new ways of approaching a problem. The key criterion for such a paper is that it makes a contribution from which other practitioners can benefit. It is not enough simply to describe a program! Submission details Submission deadline: 2 June 2006 Notification:3 July 2006 Submitted papers should be in postscript or portable document format, formatted using the ACM SIGPLAN style guidelines. The length should be restricted to 12 pages. Detailed submission instructions will be available at http://haskell.org/haskell-workshop/2006. Accepted papers will be published by the ACM and will appear in the ACM Digital Library. If there is sufficient demand, we will try to organise a time slot for system or tool demonstrations. If you are interested in demonstrating a Haskell related tool or application, please send a brief demo proposal to Andres Loeh ([EMAIL PROTECTED]). Programme Committee Koen Claessen, Chalmers University, Sweden Bastiaan Heeren, Universiteit Utrecht, The Netherlands Paul Hudak, Yale University, US Isaac Jones, Galois Connections, US Gabriele Keller, University of New South Wales, Australia Oleg Kiselyov, FNMOC, US Andres Loeh (chair), Universitaet Bonn, Germany Conor McBride, University of Nottingham, UK Shin-Cheng Mu, Academia Sinica, Taiwan Andrew Tolmach, Portland State University, US ___ Haskell mailing list Haskell@haskell.org http://www.haskell.org/mailman/listinfo/haskell
[Haskell] Question for the haskell implementors: Arrays, unsafePerformIO, runST
So, I finally decided that jhc needs real arrays, but am running into an issue and was wondering how other compilers solve it, or if there is a general accepted way to do so. here is what I have so far -- The opaque internal array type data Array__ a -- the array transformer quasi-monad newtype AT a = AT (Array__ - Array__) seqAT__ :: AT a - AT a - AT a seqAT__ (AT a1) (AT a2) = AT $ \a - a2 (a1 a) doneAT__ :: AT a doneAT__ = AT id newAT__ :: Int - AT a - Array__ a newAT__ n (AT a1) = a1 (prim_newAT__ n) writeAT__ :: Int - a - AT a writeAT__ i x = AT $ \a - prim_writeAT__ i x a -- none of these routines have run-time checks foreign import primitive prim_newAT__ :: Int - Array__ -- performs *update-in-place* foreign import primitive prim_writeAT__ :: Int - a - Array__ - Array__ foreign import primitive unsafeAt__ :: Array__ a - Int - a -- example use newArray :: [a] - Array__ a newArray xs = newAT__ (length as) $ foldr assign doneAT (zip [0..] xs) where assign (i,v) rs = writeAT__ i v `seqAT__` rs now, the problem occurs in newAT__ newAT__ :: Int - AT a - Array__ a newAT__ n (AT a1) = a1 (prim_newAT__ n) ^ this gets floated out as a CAF. it all seems good, but the call to (prim_newAT__ n) is a constant and hence gets pulled to the top level and all arrays end up being the same array! this is no good. I always knew in the back of my mind that 'unsafePerformIO' had the same problem, but sort of punted solving it since unsafePerformIO is not really used in any critical paths. However, it pretty much fundamentally breaks arrays! I imagine the same issue would arise with runST. so, any idea how to solve it? I could brute force it and make the compiler recognize calles to prim_newAT__ as special, but I really don't like that idea. it is hard to guarentee such things across all possible optimizations and I'd like a general solution rather than hardcoding a bunch of routines as special. So far, my best idea though I don't know if it will work is adding a primitive: foreign import primitive prim_newWorld__ :: forall a . a - World__ which will throw away its argument and produce a World__. but since it is primtive, the compiler will assume the world it returns might depend on its argument. then I could do something like: foreign import primitive prim_newAT__ :: World__ - Int - Array__ newAT__ :: Int - AT a - Array__ a newAT__ n (AT a1) = a1 (prim_newAT__ (prim_newWorld__ a1) n) so the initial call to newAT__ now depends on the array transformer and can't be floated out as a CAF. I have reduced several magic primitives to just one, the world creation one. but I am still not sure how happy I am about it and wanted to know what other compilers did. John -- John Meacham - ⑆repetae.net⑆john⑈ ___ Haskell mailing list Haskell@haskell.org http://www.haskell.org/mailman/listinfo/haskell
Re: [Haskell] Question for the haskell implementors: Arrays, unsafePerformIO, runST
On 2/15/06, John Meacham [EMAIL PROTECTED] wrote: foreign import primitive prim_newWorld__ :: forall a . a - World__ which will throw away its argument and produce a World__. but since it is primtive, the compiler will assume the world it returns might depend on its argument. then I could do something like: GHC uses ST, which uses RealWorld#... -- Taral [EMAIL PROTECTED] Computer science is no more about computers than astronomy is about telescopes. -- Edsger Dijkstra ___ Haskell mailing list Haskell@haskell.org http://www.haskell.org/mailman/listinfo/haskell
Re: [Haskell-cafe] Haskell XSLT interpreter?
Has anyone written a pure haskell xslt interpreter? If not, how difficult would it be to do so? A master student of mine implemented XSLT in Haskell a couple of years ago. I've uploaded his thesis on http://www.cs.uu.nl/~johanj/MSc/danny.pdf If you're interested in the code, mail me. His implementation is partially in Haskell, partially in attribute grammar code (which generates Haskell using the Utrecht AG system). The code hasn't been used since 2001, so it might contain some bitrot. -- Johan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Layout processing
Hi,
Is it possible to ask GHC or other Haskell compiler to generate a
Haskell source file just after the processing of layout? I.e., I would
like to see this:
main = do
a - some_function
Transformed into this:
main = do {a - some_function;
I thought that would be usefull to understand better how layout works.
Thanks,
Maurício
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[Haskell-cafe] Haskell as scripting language?
Is there a way to use haskell as scripting language in a) your own project? b) other projects such as vim (beeing written in C)? At the moment I'm interested, I don't have any real project.. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: strict Haskell dialect
John Meacham [EMAIL PROTECTED] writes: there are actually several ways to implement IO. There is a paper about it somewhere that explores various methods, but I can't seem to find it, does anyone know which one i am thinking of? I know it at least explores the state and continuation versions as well as some that don't use monads I thought. It was either part of a general paper on monads or something specific to doing IO... This one? http://research.microsoft.com/~simonpj/Papers/imperative.ps.Z ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Haskell as scripting language?
For scenario (a) you can use hs-plugins and ghc http://www.cse.unsw.edu.au/~dons/hs-plugins/ With hs-plugins you can get an eval command, or you can dynamically load Haskell modules (from source or pre-compiled .o files). GHC (= 6.5) has an API that you can access from Haskell programs: http://www.haskell.org/haskellwiki/GHC/As_a_library I was wondering if the new GHC API gives you everything hs-plugins does? If not will it ultimately do what hs-plugins does and replace it, in the future? Jared. On 2/15/06, Marc Weber [EMAIL PROTECTED] wrote: Is there a way to use haskell as scripting language in a) your own project? b) other projects such as vim (beeing written in C)? At the moment I'm interested, I don't have any real project.. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe -- http://www.updike.org/~jared/ reverse )-: ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Hashtable woes
On Wed, Feb 15, 2006 at 09:42:10AM +0100, Ketil Malde wrote: Not sure how relevant this is, but I see there is a recently released hash library here that might be a candidate for FFIing? https://sourceforge.net/projects/goog-sparsehash/ | An extremely memory-efficient hash_map implementation. 2 bits/entry | overhead! The SparseHash library contains several hash-map | implementations, including implementations that optimize for space | or speed. If we want really fast maps, we should be using this. it beats the competition by far: http://judy.sourceforge.net/ John -- John Meacham - ⑆repetae.net⑆john⑈ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Hashtable woes
On Feb 15, 2006, at 3:42 AM, Ketil Malde wrote: Not sure how relevant this is, but I see there is a recently released hash library here that might be a candidate for FFIing? https://sourceforge.net/projects/goog-sparsehash/ The real issue isn't the algorithms involved; I saw the best performance from the stupidest hash algorithm (well, and switching to multiplicative hashing rather than mod-k). The problem is GC of hash table elements. FFI-ing this library would give us really good algorithms, but the GC would all indirect through the FFI and I'd expect that to make things *worse*, not better. -Jan | An extremely memory-efficient hash_map implementation. 2 bits/entry | overhead! The SparseHash library contains several hash-map | implementations, including implementations that optimize for space | or speed. -k -- If I haven't seen further, it is by standing in the footprints of giants ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: strict Haskell dialect
On Wed, Feb 15, 2006 at 04:58:34PM +0100, Johan Bockgård wrote: John Meacham [EMAIL PROTECTED] writes: there are actually several ways to implement IO. There is a paper about it somewhere that explores various methods, but I can't seem to find it, does anyone know which one i am thinking of? I know it at least explores the state and continuation versions as well as some that don't use monads I thought. It was either part of a general paper on monads or something specific to doing IO... This one? http://research.microsoft.com/~simonpj/Papers/imperative.ps.Z Ah, yes. perhaps we could get a local copy of every paper somewhere on haskell.org so we can do a scholar.google.com search with site:haskell.org to get full text search of all relevant haskell papers. John -- John Meacham - ⑆repetae.net⑆john⑈ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Haskell as scripting language?
jupdike: For scenario (a) you can use hs-plugins and ghc http://www.cse.unsw.edu.au/~dons/hs-plugins/ With hs-plugins you can get an eval command, or you can dynamically load Haskell modules (from source or pre-compiled .o files). GHC (= 6.5) has an API that you can access from Haskell programs: http://www.haskell.org/haskellwiki/GHC/As_a_library I was wondering if the new GHC API gives you everything hs-plugins does? If not will it ultimately do what hs-plugins does and replace it, in the future? It doesn't have the high level api. Sean Seefried actually implemented an hs-plugins-like interface to some bits of GHC, and I'd expect that hs-plugins 2 will just be a layer over ghc-api (or maybe part of ghc-api). Certainly the object loading and (ghci-based) evaluation could be moved from hs-plugins to ghc-api. The file merging operations, and possibly the native-code evaluation would require adding a layer over ghc-api. -- Don ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Haskell' Status
I'll try to occasionally post an announcement of the the status of Haskell'[1], the next Haskell standard, so that you can all be aware of my thinking, and our current place in the timeline. There is a list of proposals and a strawman categorization of them on the wiki[2]. The categorization reflects someone's current thinking about what's in and out, but it's really just for discussion at this phase. The timeline for this effort is also on the wiki[4]. You'll notice that it's very aggressive; we plan to announce something at the next Haskell Workshop in September. Our current spot in the timeline is that we're meant to be brainstorming, discussing, and refining proposals. I've just posted some leading questions [3] in order to focus the discussion a bit. I can't help but notice that there is a lot of excitement (and support?) for a larger standard; one that would have a bigger impact. I think that part of the Haskell' effort should be to make a plan for moving forward. At the very least we should have a set of recommendations for what the community needs to work on between this and the next standard; what are the most promising proposals and what needs to happen to make them a reality. I think that the wiki will be a great resource for any future standard, and we should work to make it as nice as possible. Please reply to the Haskell' mailing list, and email me if you have any questions. peace, isaac [1] Haskell' Wiki: http://hackage.haskell.org/trac/haskell-prime [2] list of proposals and strawman categorization: http://hackage.haskell.org/trac/haskell-prime/report/9 [3] plan for moving discussion forward http://www.haskell.org//pipermail/haskell-prime/2006-February/000582.html [4] The TimeLine is here. Ascii text of the timeline follows (might not make sense unless you use a proportional font: http://hackage.haskell.org/trac/haskell-prime/wiki/TimeLine Write ReportReview | | Edit| Discuss / Refine--|--| | | | || | brainstorm--- | || | | | | | || | setup | | | || | | | | | || | --- 10 | 11 | 12 | 01 | 02 | 03 | 04 | 05 | 06 | 07 | 08 | 09 | 10 | 11 2005 2006 --- | | | | | | Face-To-Face? | StrawmanTrial Decision Announce @HW ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Code completion? (IDE)?
vim7 has introduced omni-completion... So I'm interested wether there are any projects which support any kind of completion.? I've read the thread about Eclipse IDE haskell plugin. Would you recommend picking up code from a haskell compiler and adapt it for this purpose? I'm interested but don't plan to implement this in the near future. Marc ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: Associated Type Synonyms question
Niklas Broberg [EMAIL PROTECTED] wrote:: On 2/10/06, Ross Paterson [EMAIL PROTECTED] wrote: On Fri, Feb 10, 2006 at 05:20:47PM +0100, Niklas Broberg wrote: - when looking at the definition of MonadWriter the Monoid constraint is not strictly necessary, and none of the other mtl monads have anything similar. Is it the assumption that this kind of constraint is never really necessary, and thus no support for it is needed for ATS? I think that's right -- it's only needed for the Monad instance for WriterT. But it is a convenience. In any instance of MonadWriter, the w will be a monoid, as there'll be a WriterT in the stack somewhere, so the Monoid constraint just saves people writing general functions with MonadWriter from having to add it. Sure it's a convenience, and thinking about it some more it would seem like that is always the case - it is never crucial to constrain a parameter. But then again, the same applies to the Monad m constraint, we could give the same argument there (all actual instances will be monads, hence...). So my other question still stands, why not allow constraints on associated types as well, as a convenience? Manuel (Chakravarty) and I agree that it should be possible to constrain associated type synonyms in the context of class definitions. Your example shows that this feature is actually needed. I will integrate it into phrac within the next few days. Stefa ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
