[GHC] #9315: Weird change in allocation numbers of T9203

[GHC]

#9315: Weird change in allocation numbers of T9203
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              Reporter:  nomeata     |             Owner:  simonmar
                  Type:  bug         |            Status:  new
              Priority:  normal      |         Milestone:
             Component:  Runtime     |           Version:  7.9
  System                             |          Keywords:
            Resolution:              |  Operating System:  Unknown/Multiple
Differential Revisions:              |   Type of failure:  None/Unknown
          Architecture:              |         Test Case:
  Unknown/Multiple                   |          Blocking:
            Difficulty:  Unknown     |
            Blocked By:              |
       Related Tickets:              |
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Description changed by jrp:

Old description:

> While trying to improve our handle on allocation numbers, I’m stuck with
> the test case T9203. On some machines, it allocates roughly 95747304
> bytes (this includes travis and my laptop), on others 42946176 bytes
> (e.g. on the machine where I monitor benchmark performance). All machines
> are 64 bit Linux machines.
>
> The output of `-ddump-simpl`, `-ddump-stg` and `-ddump-cmm` is identical
> (up to variable names). Even `-ddump-asm` looks the same, besides some
> jump target reordering. The binary runs too small to get a heap profile.
>
> I’m a bit stuck here: What can be the cause for these differences?
>
> (BTW, if have an up-to-date GHC tree, can you report the number you get?
> Run `make -C testsuite VERBOSE=4 TEST=9203` for that.)

New description:

 While trying to improve our handle on allocation numbers, I’m stuck with
 the test case T9203. On some machines, it allocates roughly 95747304 bytes
 (this includes travis and my laptop), on others 42946176 bytes (e.g. on
 the machine where I monitor benchmark performance). All machines are 64
 bit Linux machines.

 The output of `-ddump-simpl`, `-ddump-stg` and `-ddump-cmm` is identical
 (up to variable names). Even `-ddump-asm` looks the same, besides some
 jump target reordering. The binary runs too small to get a heap profile.

 I’m a bit stuck here: What can be the cause for these differences?

 (BTW, if have an up-to-date GHC tree, can you report the number you get?
 Run `make -C testsuite VERBOSE=4 TEST=T9203` for that.)

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9315#comment:8>
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