Re: [gentoo-dev] GCC 3 Vs GCC 2 and some other stuff

[Spider <spider@gentoo.org>]

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I know well that this is was completely unscientific and unreproductible
behaviour, with only one run and so on.

PDC20265: chipset revision 2
PDC20265: not 100% native mode: will probe irqs later
PDC20265: (U)DMA Burst Bit ENABLED Primary PCI Mode Secondary PCI Mode.
    ide2: BM-DMA at 0x7400-0x7407, BIOS settings: hde:DMA, hdf:pio
    ide3: BM-DMA at 0x7408-0x740f, BIOS settings: hdg:pio, hdh:pio

hde: Maxtor 5T030H3, ATA DISK drive
its an Athlon t-bird 1GHz
MemTotal:       288548 kB
(PC-100 SDRAM)

Filesystem on the drive used for compilations are ReiserFS.

Using r5 hash to sort names
ReiserFS version 3.6.25

also, the fact that I dont use the same compiler flags for both
compilers are a dead giveaway.

Better code, I can't speak for. More tests, I can, I've had to patch up
some c++ code in order to fit the stricter tests, something I consider
good.


cpu idle time doesn't matter much when diskaccess is ventured, should I
ever intend to do a good benchmark I'd use tmpfs for the whole process,
and make sure I dont run out of RAM while doing it. This is a user
comparsion, the feeling of how long things take to compile c++. 

And yes, the machine was in "normal use" at the time. Xchat, sylpheed
and some aterm's.  bad behaviour for a benchmarker. But standard for me
whenever I compile things, and thats how I wanted the comparsion done.

kernel is for once the default gentoo one, something I seldom use
normally. (I prefer -jam series)

//Spider



> 
> So, regarding your benchmarks Spider. There is something wrong,
> definately. And I think our gentoo kernel heads around here should
> take a close look at it. Sure, GCC 3.X *is* slower on compilation
> time, however, your tests show a very disturbing fact: Under some
> circumstances, your CPU seems to spend unreasonable amount of time not
> doing anything. This could be an indication of a bigger issue,
> possibly a configuration or a hardware issue. There might be an  issue
> going on with the cache or the filesystem or even the loader. How much
> memory the PC you used has and what kind of drive and filesystem did
> you use? (I hope that all this is not a side effect of one of the
> Gentoo kernel patches...)
> 


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