Re: RFC: outb 0x80 in inb_p, outb_p harmful on some modern AMD64 with MCP51 laptops

Paul Rolland
2007-12-11T15:38:18Z

Hello,

On Tue, 11 Dec 2007 16:28:56 +0100
Rene Herman <rene.herman@keyaccess.nl> wrote:

> On 11-12-07 15:15, Rene Herman wrote:
>
> > On 11-12-07 14:32, Paul Rolland wrote:
> >
> This might be a bit more constant, I suppose. This serialises with cpuid.
> Don't see a difference locally, but perhaps you do.
Well, yes, at least on the PIII and the Opteron... Core2 is still changing
a lot...

> On a Duron 1300 with an actual ISA bus, "out" is between 1300 and 1600 for
> me and "in" between 1200 and 1500 with a few flukes above that which will I
> suppose be caused by the bus (ISA _or_ PCI) being momentarily busy or some
> such...
The results :

Core 2Duo 1.73 GHz :
[root@tux tmp]# ./in2
out: 2777
in : 2519
[root@tux tmp]# ./in2
out: 2440
in : 2391
[root@tux tmp]# ./in2
out: 2460
in : 2388

Pentium III :
[root@www-dev /tmp]# ./in2
out: 746
in : 747
[root@www-dev /tmp]# ./in2
out: 746
in : 747
[root@www-dev /tmp]# ./in2
out: 746
in : 745

AMD Opteron 150 :
-bash-3.1# ./in2
out: 4846
in : 4845
-bash-3.1# ./in2
out: 4846
in : 4846
-bash-3.1# ./in2
out: 4846
in : 4845

Paul