- jhc - Haskell.org

darcs patch: Fix bug in E.Subst.
by Lemmih 23 Feb '08

23 Feb '08

Sat Feb 23 15:00:47 CET 2008 Lemmih <lemmih(a)gmail.com> * Fix bug in E.Subst.

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darcs patch: Cache a few items, this gives a 20% speed bump.
by Lemmih 22 Feb '08

22 Feb '08

Fri Feb 22 12:59:49 CET 2008 Lemmih <lemmih(a)gmail.com> * Cache a few items, this gives a 20% speed bump.

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darcs patch: Use an IdMap in E.Demand. This gives an 18% speed-up a...
by Lemmih 22 Feb '08

22 Feb '08

Fri Feb 22 03:14:45 CET 2008 Lemmih <lemmih(a)gmail.com> * Use an IdMap in E.Demand. This gives an 18% speed-up and smaller ho files.

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Atoms, Infos and unique ids.
by Lemmih 22 Feb '08

22 Feb '08

Hiya, TVr's can be large and are duplicated many times over. We avoid duplicating Info and type information by clearing all variables and restoring them from their binding point. Atoms are very similar to Infos in this regard: they're large enough that we don't want to keep multiple copies around. However, atoms are currently dealt with in an unsafe (see 'getMap') and inefficient manner (10mb (40%) in base-1.0.hl is wasted on duplicate strings). It is my understanding that atoms could be stored exactly like Infos. I tried to implement this but, unfortunately, atoms are frequently being relied on for unique ids. Some cases are easy to fix, others less so. John, do you have time to document the intended behavior in the difficult cases? -- Cheers, Lemmih

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jhc backend
by Csaba Hruska 20 Feb '08

20 Feb '08

Hi! Will jhc strictly generate only c code ? I know the llvm compiler framework (llvm.org) and what do you think of using llvm for (imperative) backend instead of current c backend. LLVM can generate c code too and it supports many platforms (X86, IA64, SPARC, ARM, MIPS, SPU, POWERPC) and also handles all platform specific stuff. LLVM uses an intermediate language (typed risk lile language), and uses SSA form. Many optimizations can be done via llvm. and llvm supports JIT (Just In Time ) compilationm, taht can be useful for interactive (interpreters) use of haskell. any opinion ? Cheers, Csaba Hruska P.S.: I'm new here so let me to introduce: My name is Csaba Hruska, i'm in the 5th year in university (BME budapest, hungary). i'm studiyng computer science.

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darcs patch: Makefile wibbles for jhcp and *.hsc
by Lemmih 20 Feb '08

20 Feb '08

Wed Feb 20 19:49:10 CET 2008 Lemmih <lemmih(a)gmail.com> * Makefile wibbles for jhcp and *.hsc

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darcs patch: Cache scoping info, avoid unnecessary maps. (and 2 more)
by Lemmih 20 Feb '08

20 Feb '08

Tue Feb 19 16:14:10 CET 2008 Lemmih <lemmih(a)gmail.com> * Cache scoping info, avoid unnecessary maps. Tue Feb 19 16:15:54 CET 2008 Lemmih <lemmih(a)gmail.com> * Remove debug code. Wed Feb 20 19:40:27 CET 2008 Lemmih <lemmih(a)gmail.com> * Add a comment describing the function of E.Subst.

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Hotspots.
by Lemmih 20 Feb '08

20 Feb '08

Greetings, I've found a few hotspots that'll be working on. I'd be very interested in discussing solutions. Performance flaws: * IdMaps are used to generate new ids. * Ho files contain huge amounts of duplicate information. * Ho files aren't saved lazily. * C code is used for generating atoms. Repeatedly mapping variables to 'const Nothing' is very expensive. It is currently the most expensive procedure in Jhc, taking ~20% CPU time when compiling the base library. The base library contains 65 megabytes of uncompressed data. Most of that is duplicate information that disappears when it is compressed. However, parsing that amount of data takes considerable time. Ho files are completely serialized before they're written to disk. Using C code for generating atoms results in no performance improvement. There are only a few cases where using C is beneficial and this is not one of them. -- Cheers, Lemmih

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Infos.
by Lemmih 20 Feb '08

20 Feb '08

Hi, In Ho/Build.hs, TVr's are stripped of Type and Info information before the Ho files are saved. I experimented with omitting Info information when saving TVr's and everything appeared to work as expected. Is there some corner case where saving the Info list is necessary? -- Cheers, Lemmih

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Optimization.
by Lemmih 19 Feb '08

19 Feb '08

Greetings, The attached patch is a two-step optimization: 1) Only call 'getType' 100,000,000 times instead of 600,000,000 times. 2) Greatly simplify the actual loop. Without this patch, compiling base-1.0.hl takes 19 minutes. With this patch, compile time is down to 11 minutes. Feedback would be greatly appreciated. -- Cheers, Lemmih

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