id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc	os	architecture	failure	difficulty	testcase	blockedby	blocking	related
3110	Setting the hard maximum heap size no longer works	dons		"
Take this source:

{{{
main = do print (product [1..])
}}}

Compile it:

{{{
$ ghc -O2 A.hs --make -o A -fforce-recomp
[1 of 1] Compiling Main             ( A.hs, A.o )
Linking A ...
}}}

Set a small maximum heap size, run the program, then kill it after a few seconds:

{{{
$ time ./A +RTS -M1M -sstderr
./A +RTS -M1M -sstderr 
^C      20,177,576 bytes allocated in the heap
          32,352 bytes copied during GC
          18,840 bytes maximum residency (1 sample(s))
          20,888 bytes maximum slop
             682 MB total memory in use (116 MB lost due to fragmentation)

  Generation 0:    38 collections,     0 parallel,  0.00s,  0.02s elapsed
  Generation 1:     1 collections,     0 parallel,  0.00s,  0.00s elapsed

  INIT  time    0.00s  (  0.00s elapsed)
  MUT   time    4.62s  (  5.24s elapsed)
  GC    time    0.00s  (  0.02s elapsed)
  EXIT  time    0.00s  (  0.00s elapsed)
  Total time    4.62s  (  5.26s elapsed)

  %GC time       0.1%  (0.4% elapsed)

  Alloc rate    4,370,879 bytes per MUT second

  Productivity  99.9% of total user, 87.8% of total elapsed


./A +RTS -M1M -sstderr  4.62s user 0.61s system 98% cpu 5.314 total
}}}

Far more memory has been allocated in the heap than the 1M max limit.

GHC 6.10.1 on Linux x86_64."	bug	closed	normal		Runtime System	6.10.1	invalid			Unknown/Multiple	Unknown/Multiple