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

["Ville Syrjälä" <syrjala@sci.fi>]

On Wed, Dec 12, 2007 at 01:57:01PM +0200, Ville Syrjälä wrote:
> On Wed, Dec 12, 2007 at 12:31:18AM +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.
> 
> vendor_id       : GenuineIntel
> cpu family      : 6
> model           : 15
> model name      : Intel(R) Core(TM)2 CPU          6600  @ 2.40GHz
> stepping        : 6
> 
> cpu MHz         : 2394.000
> cycles: out 1830, in 1166
> 
> cpu MHz         : 1596.000
> cycles: out 1925, in 1266

BTW that was my home desktop. I just noticed that my work desktop gives out
significantly different results.

vendor_id       : GenuineIntel
cpu family      : 6
model           : 15
model name      : Intel(R) Core(TM)2 CPU          6700  @ 2.66GHz
stepping        : 6

cpu MHz         : 2667.000
cycles: out 4263, in 2487

cpu MHz         : 1600.000
cycles: out 4391, in 2623

There seems to be more variation in the results between runs on this system
too. I suppose the difference must be up to the chipset.

My home system:
00:00.0 Host bridge: Intel Corporation 82P965/G965 Memory Controller Hub (rev 02)
00:1f.0 ISA bridge: Intel Corporation 82801HB/HR (ICH8/R) LPC Interface Controller (rev 02)

My work system:
00:00.0 Host bridge: Intel Corporation 82975X Memory Controller Hub
00:1f.0 ISA bridge: Intel Corporation 82801GB/GR (ICH7 Family) LPC Interface Bridge (rev 01)

-- 
Ville Syrjälä
syrjala@sci.fi
http://www.sci.fi/~syrjala/