Turning on -funbox-small-strict-fields by default in GHC 7.8

Austin Seipp aseipp at pobox.com
Fri Apr 26 20:13:14 CEST 2013


+1 from me.

On Fri, Apr 26, 2013 at 1:00 PM, Johan Tibell <johan.tibell at gmail.com> wrote:
> On Thu, Apr 25, 2013 at 9:56 AM, Johan Tibell <johan.tibell at gmail.com>
> wrote:
>>
>>
>> Benchmark some large program that isn't carefully tuned by using
>> strictness in just the right places (like our core libraries tend to be), to
>> make sure this change doesn't hurt performance there. I nomiate GHC as the
>> candidate program for this test.
>
>
> Here are the nofib compile times of unmodified GHC vs GHC compiled with
> -funbox-strict-fields:
>
>         -1 s.d.                -----           -3.3%
>         +1 s.d.                -----           +2.5%
>         Average                -----           -0.4%
>
> (I compiled GHC by adding the flag to GhcStage2HcOpts and GhcLibHcOpts.)
>
> I can't tell if this is noise or not. At least the compile times seem to
> have gone down every so slightly.
>
> With these three tests out of the way, are people happy with me turning on
> the flag by default for the 7.8 release?
>
>
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-- 
Regards,
Austin - PGP: 4096R/0x91384671



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