#7258: Compiling DynFlags is jolly slow
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Reporter: simonpj | Owner: simonpj
Type: bug | Status: new
Priority: normal | Milestone: 7.8.1
Component: Compiler | Version: 7.6.1
Keywords: | Os: Unknown/Multiple
Architecture: Unknown/Multiple | Failure: None/Unknown
Difficulty: Unknown | Testcase:
Blockedby: | Blocking:
Related: |
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Comment(by simonpj):
OK I have verified that the changes to the occurrence analyser (above)
make essentially zero different to nofib numbers. It's a very worthwhile
simplification, because it completely gets rid of the `getProxies` stuff
that was eating all the time before.
Alas, compiling W2 is still non-linear. Here's the allocation by the
stage-2 compiler
* 50 fields: 1.01 Gbyte
* 100 fields: 2.98 Gbyte
* 200 fields: 9.64 Gbyte
This is after including the improvements to the derived `Read` code in
#7450.
So something is still wrong. Need to do some profilling to find out.
There are some very deeply nested lambdas, which lead to SRTs of ever-
increasing size, so there is definitely a quadratic effect there. But I'm
not sure that is all.
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7258#comment:12>
GHC <http://www.haskell.org/ghc/>
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