Re: Testsuite ad RedHat 7

[Michael Meding <Michael at Meding dot net>]

Hi there,

> Note that the 2.95 branch is fairly good. It is *quite* known that gcc 2.95
> has issues with optimizations larger than -O2.

is there a paper out that, which describes or mentiones what are the
does and don'ts with gcc-2.95.2 and higher optimizations or
archichtectural optimizations ?

> 
> One goal of 3.0 is to get things more stable in that regards.
> 
> Who would dare to use large optimizations on gcc 2.95.x except for those
> daredevil linux people anyways ?

Let's put it this way, why there are people out there who are willing to
pay a more than 50percent price rise in the tag for a 5 or 10 percent
faster processor ? There is great potential in tailoring the distro's or
better to say the time critical apps to a certain extent to specific
processors and their futures. 

If I can gain 10 percent of speed if using another set of compiler
switches or another compiler, why shouldn't I do this when gaining this
percent in hardware may double the cost of the cpu ? The potential of
some cpu's on the market (i.e. athlon, duron, thunderbird) is quite huge
when the software is compiled with the right compiler and or the right
optimization switches.

As of now there is little market for distros which are allegedly faster
due to their optimization for a specific processor set. But eying the
price differences in cpu's there should and will be mor emphasiz in the
future. Gaining a couple of percent's maybe of extensive costs on the
hardware side and maybe obtained for free when using the right flags....

So why there are not more distros which ships in different cpu flavors ?
Maybe it is because at the moment the competition is not very dense.
Maybe the compiler builders are happy when they get stable code through,
not to speak of fast one.

> 
> Minor flame: in my opinion, ceasing all development on the 2.95 branch
> precipitated the problem. Not having frequent enough FSF releases is another
> part of the problem. When lots of packages have critical bugs that are only
> fixed in development versions, when actual maintainers who should know better
> brew their own major linux releases on top of development snapshots, suddenly
> the distinction between `stable' and `highly experimental' blurs.

Question in here is, of which are actually compiler related ? Which are
glibc related ?

It would have been surely nice, to have a little bit more of information
available of the pros and cons of gcc-2.91.66 or 2.95.1 or 2.95.2 . Or
more intermediate releases.

I myself haven't been able to find pages that explain the differences
between the compilers, despite looking through the mail archives. Not to
speak of compiler benchmarks tested on various platforms with various
software.

If somebody knows something about this matter and could point me to the
right pages that would be nice, if there are any pages out there
adressing those issues (for example which switches to use best on which
processor type and model, on average).


Greetings

Michael