On Wed, 2007-12-12 at 00:31 +0100, Rene Herman wrote:
> Good day.
>
> Would some people on x86 (both 32 and 64) be kind enough to compile and run
> the attached program? This is about testing how long I/O port access to port
> 0x80 takes. It measures in CPU cycles so CPU speed is crucial in reporting.
>
> Posted a previous incarnation of this before, buried in the outb 0x80 thread
> which had a serialising problem. This one should as far as I can see measure
> the right thing though. Please yell if you disagree...
>
> For me, on a Duron 1300 (AMD756 chipset) I have a constant:
>
> rene@7ixe4:~/src/port80$ su -c ./port80
> cycles: out 2400, in 2400
>
> and on a PII 400 (Intel 440BX chipset) a constant:
>
> rene@6bap:~/src/port80$ su -c ./port80
> cycles: out 553, in 251
>
> Results are (mostly) independent of compiler optimisation, but testing with
> an -O2 compile should be most useful. Thanks!
Since a lot of people reported timings for all the fancy new x86_64
hardware, I've not included those. Timings for my ancient machines still
in service:
$ gcc -o port80 -O2 port80.c
$ sudo ./port80
cycles: out 1736, in 1735
$ sudo ./port80
cycles: out 1831, in 1827
$ sudo ./port80
cycles: out 1735, in 1735
$ sudo ./port80
cycles: out 1743, in 1737
$ sudo ./port80
cycles: out 1737, in 1734
$ cat /proc/cpuinfo
processor : 0
vendor_id : AuthenticAMD
cpu family : 6
model : 6
model name : AMD Athlon(tm) MP 1800+
stepping : 2
cpu MHz : 1533.420
cache size : 256 KB
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 1
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge
mca cmov
pat pse36 mmx fxsr sse syscall mp mmxext 3dnowext 3dnow ts
bogomips : 3069.09
clflush size : 32
processor : 1
vendor_id : AuthenticAMD
cpu family : 6
model : 6
model name : AMD Athlon(tm) Processor
stepping : 2
cpu MHz : 1533.420
cache size : 256 KB
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 1
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge
mca cmov pat pse36 mmx fxsr sse syscall mp mmxext 3dnowext 3dnow ts
bogomips : 3067.07
clflush size : 32
---
# ./port80
cycles: out 812, in 354
# ./port80
cycles: out 811, in 354
# ./port80
cycles: out 811, in 354
# ./port80
cycles: out 811, in 354
# cat /proc/cpuinfo
processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 8
model name : Pentium III (Coppermine)
stepping : 1
cpu MHz : 672.071
cache size : 256 KB
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 2
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge
mca cmov pat pse36 mmx fxsr sse
bogomips : 1331.20
---
# ./port80
cycles: out 116, in 47
# ./port80
cycles: out 116, in 47
# ./port80
cycles: out 116, in 47
# ./port80
cycles: out 116, in 47
# cat /proc/cpuinfo
processor : 0
vendor_id : GenuineIntel
cpu family : 5
model : 2
model name : Pentium 75 - 200
stepping : 12
cpu MHz : 99.476
fdiv_bug : no
hlt_bug : no
f00f_bug : yes
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 1
wp : yes
flags : fpu vme de pse tsc msr mce cx8
bogomips : 198.24
P133 clocked at 100MHz
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