#10717: fannkuch-redux allocations increase by factor of 10000 between 7.4.2 and 7.6.3 -------------------------------------+------------------------------------- Reporter: bgamari | Owner: Type: bug | Status: new Priority: normal | Milestone: 7.12.1 Component: Compiler | Version: 7.6.3 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Runtime | Unknown/Multiple performance bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Revisions: -------------------------------------+------------------------------------- Comment (by bgamari): I'm now looking at the ticky output from the testcase run with argument `11` after having confirmed that compiling with `-prof` kills the effect (both compilers produce executables which allocate heavily). The ticky output shows a pretty clear difference. == 7.6 == {{{ ENTERS: 1178454454 of which 1178454454 (100.0%) direct to the entry code [the rest indirected via Node's info ptr] 36288010 ( 3.1%) thunks 0 ( 0.0%) data values 0 ( 0.0%) normal indirections 0 ( 0.0%) permanent indirections ... RETURNS: 354136250 36288000 ( 10.2%) from entering a new constructor [the rest from entering an existing constructor] UPDATE FRAMES: 36288007 (0 omitted from thunks) ... Entries Allocs Arity Stack Kinds Function -------------------------------------------------------------------------------- ... 39916804 108864012 4 0 iiiA $wa3{v s3Cl} (main:Main) }}} == 7.4 == {{{ ENTERS: 1142166456 of which 1142166456 (100.0%) direct to the entry code [the rest indirected via Node's info ptr] 10 ( 0.0%) thunks 0 ( 0.0%) data values 0 ( 0.0%) normal indirections 0 ( 0.0%) permanent indirections ... RETURNS: 317848252 0 ( 0.0%) from entering a new constructor [the rest from entering an existing constructor] UPDATE FRAMES: 7 (0 omitted from thunks) ... Entries Allocs Arity Stack Kinds Function -------------------------------------------------------------------------------- ... 39916804 12 4 0 iiiA $wa3{v s3ad} (main:Main) }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10717#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler