[GHC] #14513: +RTS -hT does not report about SmallArray objects

23 Nov 2017


      #14513: +RTS -hT does not report about SmallArray objects
-------------------------------------+-------------------------------------
           Reporter:  akio           |             Owner:  (none)
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:
          Component:  Runtime        |           Version:  8.2.1
  System                             |
           Keywords:  profiling      |  Operating System:  Linux
       Architecture:                 |   Type of failure:  Incorrect result
  Unknown/Multiple                   |  at runtime
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
-------------------------------------+-------------------------------------
 +RTS -hT seems to ignore SmallArray# objects. Also the combination of
 SmallArray# objects and -hT causes a segfault on ghc 7.10.

 To reproduce, save the following progam as smallarray.hs

 {{{#!hs
 {-# LANGUAGE MagicHash #-}
 {-# LANGUAGE BangPatterns #-}
 {-# LANGUAGE UnboxedTuples #-}
 import GHC.Exts
 import GHC.IO (IO(..), unIO)
 import Control.Concurrent
 import Control.Monad
 import System.Mem

 main :: IO ()
 main = do
   forkIO $ forever $ performGC
   IO $ \s0 ->
     let
       !(# s01, msa #) = newSmallArray# 100# 'X' s0
       !s02 = writeSmallArray# msa 4# 'Y' s01
       !(# s1, sa #) = unsafeFreezeSmallArray# msa s02
       !(# s2, () #) = unIO (threadDelay 5000000) s1
       !(# v #) = indexSmallArray# sa 2#
       !(# s3, () #) = unIO (print v) s2
     in (# s3, () #)
 }}}

 compile it, and run it like:

 {{{
 ghc smallarray.hs -rtsopts -threaded
 ./samllarray +RTS -hT
 }}}

-- 
Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14513
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