[GHC] #11645: Heap profiling - hp2ps: samples out of sequence

[GHC]

#11645: Heap profiling - hp2ps: samples out of sequence
-------------------------------------+-------------------------------------
           Reporter:  thomie         |             Owner:
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:
          Component:  Profiling      |           Version:  8.0.1-rc2
           Keywords:                 |  Operating System:  Unknown/Multiple
       Architecture:                 |   Type of failure:  None/Unknown
  Unknown/Multiple                   |
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:  #664
Differential Rev(s):                 |         Wiki Page:
-------------------------------------+-------------------------------------
 `make TEST=hpc_fork WAY=prof` is failing, but it has nothing to do with
 `hpc`.

 {{{
 hp2ps: hpc_fork.hp, line 9, samples out of sequence
 hp2ps error when processing heap profile for hpc_fork
 }}}

 hpc_fork.hs:
 {{{
 module main where

 import system.posix.process
 import control.concurrent

 main = do
   pid1 <- forkprocess $ do threaddelay 100000
   pid2 <- forkprocess $ do threaddelay 100000
   print ()
 }}}

 To reproduce:

 {{{
 $ ghc-8.0.1 hpc_fork.hs -fforce-recomp -prof
 $ ./hpc_fork +RTS -hc
 $ hp2ps hpc_fork.hp
 }}}

 Example hpc_fork.hp:
 {{{
 JOB "hpc_fork +RTS -hc"
 DATE "Thu Feb 25 22:37 2016"
 SAMPLE_UNIT "seconds"
 VALUE_UNIT "bytes"
 BEGIN_SAMPLE 0.000000
 END_SAMPLE 0.000000
 BEGIN_SAMPLE 0.005672
 END_SAMPLE 0.005672
 BEGIN_SAMPLE 0.003167
 END_SAMPLE 0.003167
 BEGIN_SAMPLE 0.003311
 END_SAMPLE 0.003311
 }}}

 This is a regression from 7.10.3.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11645>
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