#5100: Stack space overflow when using -N2 and not with -N1
-------------------------------+--------------------------------------------
Reporter: mitar | Owner:
Type: bug | Status: new
Priority: normal | Component: Compiler
Version: 7.1 | Keywords:
Testcase: | Blockedby:
Os: Linux | Blocking:
Architecture: x86_64 (amd64) | Failure: None/Unknown
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I get a stack space overflow error when using -N2 (or -N4), but the
program works with -N1. The program is my test and benchmarking program
for [http://hackage.haskell.org/package/Etage-Graph Etage-Graph] package.
So this works normally: `./etage-graph-test -s 10 +RTS -N1`
{{{
Generating a random graph of size 10.
Graph contains 10 nodes.
Dijkstra search time for shortest paths: 0.000875s
Etage search time for shortest paths: 0.010341s (0.5s timeout)
Found 100.00 % shortest paths.
etage-graph-test: DissolvingException "()"
}}}
But this does not: `./etage-graph-test -s 10 +RTS -N2`
{{{
Generating a random graph of size 10.
Graph contains 10 nodes.
Stack space overflow: current size 8388608 bytes.
Use `+RTS -Ksize -RTS' to increase it.
}}}
The most interesting thing is that this happens only for graph sizes (-s
parameter) between (including) 1-19. For larger sizes it works without
problems. What means that the problem is this line:
{{{
map spFromSource (nodes graph) `using` parListChunk (noNodes graph `div`
(numCapabilities * 10)) rdeepseq
}}}
Yes. So also `/etage-graph-test -s 5 +RTS -N1` fails. OK, so
`parListChunk` with 0 as an argument is not well defined, or it is defined
to diverge. Is this a wanted feature or it is a bug?
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/5100>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
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