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

[Geert Bevin <gbevin@uwyn.com>]

What were you benchmarking since you never even mentioned that, the
compilation of the software or the resulting executable's performance.
The first one seems pretty useless to me, while the latter does make
sense.

On Mon, 2002-04-08 at 04:46, Spider wrote:
> 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...)
> > 
> 
> 
> --
> begin  happy99.exe
> This is a .signature virus! Please copy me into your .signature!
> See Microsoft KB Article Q265230 for more information.
> end
-- 
Geert Bevin             Uwyn
"Use what you need"     Lambermontlaan 148
http://www.uwyn.com     1030 Brussels
gbevin@uwyn.com         Tel & Fax +32 2 245 41 06