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Re: K6-II+, persistent strange test results of glibc-2.2.3
- To: Byeong-ryeol Kim <jinbo21 at hananet dot net>
- Subject: Re: K6-II+, persistent strange test results of glibc-2.2.3
- From: Andreas Jaeger <aj at suse dot de>
- Date: 29 Apr 2001 11:25:26 +0200
- Cc: Ulrich Drepper <drepper at cygnus dot com>, <libc-alpha at sourceware dot cygnus dot com>
- References: <Pine.LNX.4.33.0104290346500.13290-100000@progress.plw.net>
Byeong-ryeol Kim <jinbo21@hananet.net> writes:
> On 28 Apr 2001, Ulrich Drepper wrote:
>
> > Byeong-ryeol Kim <jinbo21@hananet.net> writes:
> >
> > > is: -2.48292386531829833984e-01 -0x1.fc80b800000000000000p-3
> > > should be: -2.51362651586532592773e-01 -0x1.01653600000000000000p-2
> > > difference: 3.07026505470275878906e-03 0x1.926d0000000000000000p-9
> > > ulp : 103021.0000
> > > max.ulp : 1.0000
> > > Maximal error of `yn'
> > > is : 103021.0000 ulp
> > > accepted: 3.0000 ulp
> >
> > This normally would suggest that the compiler is broken and you should
> > use a better one.
> ....
>
> I'll try to test with latest gcc 3.1 pre-release, later.
>
> > If you say that running the same binary produces different results
> > (and since this is not the case anywhere else) it's either a kernel or
> > a CPU problem. AMD's FPU is lousy and I wouldn't be surprised at all.
> ...
> If these problems were related with kernel, which version of kernel
> would be adequate for glibc-2.2.3?
>
> Yes, I know, AMD CPUs prior to Athlons have deficiency in FPU-intensive
> work, and I admit my CPU has serious problem, prepared to give up this
> CPU.
Please run the same binary (with the same libm and libc) on another
machine to check whether the CPU or the compiler is broken.
> But, why problems I mentioned in previous mail appear these
> days(2.2.3preX era), are newly added math functions revealing the
> workarounded CPU problems explicitly?
> If those were due to the deficiency of FPU of AMD CPUs, is this
> statement interpretable that AMD CPUs(though not all) are not adequate
> for FPU-intensive work or development platform of FPU-intensive programs?
> If so, How about Athlon or Duron family?
I don't have problem with the gcc 3.0 branch on athlons.
Andreas
--
Andreas Jaeger
SuSE Labs aj@suse.de
private aj@arthur.inka.de
http://www.suse.de/~aj