[GHC] #11542: Profiling call count frequently 0 when it shouldn't be

[GHC]

#11542: Profiling call count frequently 0 when it shouldn't be
-------------------------------------+-------------------------------------
        Reporter:  augustss          |                Owner:
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Profiling         |              Version:  7.8.3
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------

Comment (by nad):

 I don't know if this is related, but I've encountered an example where the
 entries count is 0, but the ''individual'' %time and %alloc numbers are
 substantial. This is using GHC 7.10.3.

 I found a report of a similar problem: Profiling trouble by Ferenc Wagner
 (https://mail.haskell.org/pipermail/glasgow-haskell-
 users/2003-January/004727.html).

 The code attached to the report compiles if you modify some haskell98
 imports:
 {{{
 sed -ri -e 's/import Complex/import Data.Complex/' -e 's/import qualified
 List/import qualified Data.List as List/' *hs
 ghc --make Show2.hs -O -auto-all -prof
 ./Show2 +RTS -p
 }}}

 When I ran this sequence of commands now I obtained a profiling report
 with the following line:
 {{{
  main                           Main                    109           0
 10.5    0.8    10.5    0.8
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11542#comment:3>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler