| Date | Wed, 12 Dec 2007 18:06:46 -0800 | From | "H. Peter Anvin" <> | Subject | Re: [RFT] Port 0x80 I/O speed |
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Jan Engelhardt wrote: > On Dec 12 2007 00:31, Rene Herman wrote: >> 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. >> > > Transmeta TM5800 CPU with nominal frequency 933 MHz, but it has a > hardware(!) 'ondemand' governor over the range of frequencies that > the user allowed scaling over, irrespective of the software governor. > (That is, if the CPU can do 300,533 and 933 MHz, and setting the > min/max to 300/533 will cause the hardware to 'ondemand' between 300 > and 533 only. And that even if 'performance' is set on the software > side - so the only way to enforce 'performance' is to actually set > min=933.) >
Actually it has two different ones (economy and performance), you can use the "longrun" utility to select which one.
Either way, all Transmeta processors have a fixed TSC, so there is no issue.
-hpa
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