memory slop

[Simon Marlow]

On 19/04/2011 14:41, Tim Docker wrote:
>
> On 14/04/2011, at 6:24 PM, Simon Marlow wrote:
>
>>
>> I made some changes to the storage manager in the runtime today, and
>> fixed the slop problem with your program. Here it is after the changes:
>>
>> 14,928,031,040 bytes allocated in the heap
>> 313,542,200 bytes copied during GC
>> 18,044,096 bytes maximum residency (7 sample(s))
>> 294,256 bytes maximum slop
>> 37 MB total memory in use (0 MB lost due to fragmentation)
>>
>> INIT time 0.00s ( 0.00s elapsed)
>> MUT time 6.38s ( 6.39s elapsed)
>> GC time 1.26s ( 1.26s elapsed)
>> EXIT time 0.00s ( 0.00s elapsed)
>> Total time 7.64s ( 7.64s elapsed)
>>
>> I think this is with a different workload than the one you used above.
>> Before the change I was getting
>>
>> 15,652,646,680 bytes allocated in the heap
>> 312,402,760 bytes copied during GC
>> 17,913,816 bytes maximum residency (9 sample(s))
>> 111,424,792 bytes maximum slop
>> 142 MB total memory in use (0 MB lost due to fragmentation)
>>
>> INIT time 0.00s ( 0.00s elapsed)
>> MUT time 8.01s ( 8.02s elapsed)
>> GC time 16.86s ( 16.89s elapsed)
>> EXIT time 0.00s ( 0.00s elapsed)
>> Total time 24.88s ( 24.91s elapsed)
>>
>> (GHC 7.0.3 on x86-64/Linux) So, a pretty dramatic improvement. I'm
>> validating the patch right now, it should be in 7.2.1.
>>
>
> This looks really promising. Let me know when the patch is available,
> and I'll try it out on my real code.

The change is already in:

 
http://hackage.haskell.org/trac/ghc/changeset/cc2ea98ac4a15e40a15e89de9e47f33e191ba393

You can build GHC yourself from the git repositories, download a 
snapshot, or wait for 7.2.1.

Cheers,
	Simon