rc040203 at freenet.de
Fri Mar 13 06:46:14 UTC 2015
On 03/12/2015 06:16 PM, Florian Weimer wrote:
> I looked at GCC, and -mtune=atom is actually -mtune=bonnell, and there
> is now -mtune=silvermont. Bay Trail and Avoton/Rangeley, the current
> SoC families, belong to Silvermont, not Bonnell.
Well, to reach the largest possible user-groups, you need to compromise
and balance the trade-offs.
So far. -mtune=atom seems to have worked well, with many users probably
not even having noticed it.
That said, to me this would mean, you'd have to prove the other -mtune=
options provide a measurable performance increase on those cpus/SoC
without breaking backward compatibility on older HW.
As far as the switch to -mtune=atom is concerned, I don't know if was
measureable, but it wasn't user-sensible on Atoms nor on i686s.
> (And no, i686 binaries aren't just for enthusiasts. I expect that users
> who run 32-bit software with them on x86_64 installations are also
I do not agree. On the user-side, i686 binaries on x86_64 are a band-aid
to help out on x86_64s in those rare occasions, when x86_64 binaries are
not available (In most cases proprietary SW)
The major difference to users on real i686-cpus, is real i686-cpus
typically are low-end CPUs, which - in comparison to x86_64-CPUs -
suffer from lack of cpu-power. I.e. there a performance boost may play a
different, more significant role than for i686-binaries on x86_64.
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