[Mageia-dev] i686 must be Pentium II ?

[Florian Hubold]

  Am 25.09.2010 17:53, schrieb Giuseppe Ghibò:
> IMHO the problem is not finding an architecture to fit the i586 or i686 rpm 
> flags, rather to find the minimum CPU and memory requirement worthwhile for a 
> decent usage. With KDE if we look at the Mandriva 2010.1, it's barely usable 
> on a P4-3000 with 1-2GB RAM, or a AMD Barton 2500. Barely means that windows 
> and applications are pretty slow to open, switching is slow, etc.; since 
> netbook are so popular we can consider the minimum requirements as those of a 
> typical 2010 netbook, which has ATOM 1.6Ghz processor and 1GB memory. In 
> other words we can consider as default the presence of the SSE instruction 
> set. ATOM has even the SSE2, which would be even better, but that would left 
> out some AMD CPU (some older AMD, like 1.2Ghz has only the 3DNow and not 
> SSE). I would drop compiling for old ISA drivers in kernel (think to some old 
> ISA 3com card, like 3C505, etc.).
>
If you have a P4 with 2GB RAM, and that is slow/sluggish with KDE4,
i think you definitely should pay more attention to KDE configuration.
We have some forum users at mandrivauser.de who run KDE4 on
machines that have less than half of the power of the machines you
describe, there it is sluggish, but still usable.
My laptop has a P4 2.8GHz with originally 512 MB RAM, it will swap
out mostly all the time if you have more openend than a browser,
but it's not slow/sluggish, and definitely usable.

More on-topic, at mandrivauser.de, some years ago we did hand-
optimized packages for i686 and Pentium M, for some bigger apps
like OpenOffice, and if you fine-tune compiler and linker flags
for every package and every arch you support, there is definitely
a measurable performance gain, sometimes as big as 15-40%,
f.ex. startup time for OOo, but not in general.

The downside of that is, optimizing compiler flags is really risky
and can't be done in general, at least not those optimizations
that really make the difference. -Os vs. -O2 is not, what i'm talking about,
it's more stuff like -funroll-loops, -ffast-math and the like.
But even Gentoo recommendations say those should be avoided,
and you have to do them on a per-package-basis.

I think we should stay with plain old i586, but the mageia-light
thing sounds like a nice idea, i must say. We should not do what fedora
has done and abandon support for those older cpus at the cost
of what? 1% performance gain? C'mon ...



PS: Sorry, wanted to get this mail out yesterday, but Thunderbird didn't want to :(