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Re: -mtune=generic for i386 backend
- From: Andi Kleen <ak at suse dot de>
- To: Jan Hubicka <jh at suse dot cz>
- Cc: gcc-patches at gcc dot gnu dot org
- Date: 18 Jan 2006 04:10:47 +0100
- Subject: Re: -mtune=generic for i386 backend
- References: <20060117232507.GK26136@kam.mff.cuni.cz.suse.lists.egcs-patches>
Jan Hubicka <jh@suse.cz> writes:
>
> Results relative to current defaults (i686 for 32bit, Opteron for 64bit)
> SPECint SPECfp
> Opteron 64bit +1.2% -1.4%
> Prescott 64bit +1.7% +28%
That's an impressive result.
> Opteron 32bit +1.0% +0.2%
> Dothan 32bit +1.6% +0.1%
> Northwood 32bit +1.1% +0.4%
> Prescott 32bit +1.6% +2.3%
> Yonath 32bit +1.5% +0.3%
>
> For prescott/nocona we also get results better than -march=prescott/nocona. H.
> J. is going to send improvents to P4 tunnings in separate patch. In both 32bit
> and 64bit mode the generic costs extra roughly 20k over default setting.
20k what? Bigger code size? If yes measured how? Did you do any
further measurements on how code size is impact from this?
Thanks,
-Andi (looking forward to using this switch in the future)