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

Paul Rolland
2007-12-11T13:33:29Z

Hello,

On Tue, 11 Dec 2007 14:16:01 +0100
Rene Herman <rene.herman@keyaccess.nl> wrote:

> On 11-12-07 13:08, David Newall wrote:
>
> > Rene Herman wrote:

> (*) some local testing shows it to be almost exactly that for both out and
> in on my own PC -- a little over. If anyone cares, see attached little test
> program. The "little over" I don't worry about. 0 us delay is also fine for
> me and if any code was _that_ fragile it would have broken long ago.

Some results :

Core 2Duo 1.73GHz :
[root@tux tmp]# ./in
out = 2366
in = 2496
[root@tux tmp]# ./in
out = 3094
in = 2379

Plain old PIII 600 MHz:
[root@www-dev /tmp]# ./in
out = 314
in = 543
[root@www-dev /tmp]# ./in
out = 319
in = 538
[root@www-dev /tmp]# ./in
out = 319
in = 550
[root@www-dev /tmp]# ./in
out = 329
in = 531

Opteron 150 2.4GHz :
-bash-3.1# ./in
out = 4801
in = 4863
-bash-3.1# ./in
out = 5041
in = 4909
-bash-3.1# ./in
out = 4829
in = 4886

Paul