On Wed, 12 Dec 2007 00:31:18 +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!
(-m32 build on x86_64)
midway:/home/rddunlap/src # ./port80
cycles: out 2702, in 1903
midway:/home/rddunlap/src # ./port80
cycles: out 2688, in 1893
midway:/home/rddunlap/src # ./port80
cycles: out 2703, in 1909
midway:/home/rddunlap/src # ./port80
cycles: out 2687, in 1893
midway:/home/rddunlap/src # ./port80
cycles: out 2687, in 1893
midway:/home/rddunlap/src # ./port80
cycles: out 2701, in 1907
midway:/home/rddunlap/src # ./port80
cycles: out 2701, in 1919
midway:/home/rddunlap/src # ./port80
cycles: out 2687, in 1893
midway:/home/rddunlap/src # ./port80
cycles: out 2701, in 1909
midway:/home/rddunlap/src # ./port80
cycles: out 2706, in 1906
/proc/cpuinfo says CPU speed is
processor : 0
vendor_id : GenuineIntel
cpu family : 15
model : 4
model name : Intel(R) Pentium(R) D CPU 3.00GHz
stepping : 4
cpu MHz : 2999.988
---
~Randy
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