Re: [RFT] Port 0x80 I/O speed

[Ondrej Zary <linux@rainbow-software.org>]

On Wednesday 12 December 2007 00:31:18 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!
>
> Rene.

Cyrix MII PR300 (225MHz), i430TX:    cycles: out 263, in 93
Pentium MMX 166MHz @133MHz, VIA VPX: cycles: out 163, in 163
Celeron 433MHz, i440BX:              cycles: out 620, in 305
Celeron 1.3GHz, i440BX:              cycles: out 2114, in 849
Celeron 1.7GHz (P4-based), i845:     cycles: out 2178, in 1651
Pentium 4 3.2GHz, i925X:             cycles: out 2824, in 1899
Xeon E5310 1.6GHz, Dell PE1950       cycles: out 2631, in 1606
Xeon 3050 2.13GHz, Dell PE860        cycles: out 3367, in 1959

-- 
Ondrej Zary