[ntp:questions] Which version of Linux works best?

Terje Mathisen "terje.mathisen at tmsw.no" at ntp.org
Fri Mar 12 06:48:18 UTC 2010

unruh wrote:
> time that the serial port ioctl returned. I know on my parallel port
> interrupt, the test I ran showed that the time between activating the
> pin on the parallel port and the parallel port interrupt service routine
> timestamping the interrupt was of the order of 1usec. It would be nice
> to see what it is for the serial port. I doubt it is much more than
> that.

You might be wrong, and this is supposedly the reason phk started using 
the parallel port in the first place:

At least some serial ports will gate their interrupt signal to the 
resolution of their internal clock frequency or hw polling interval, 
which can result in multiple us's of delay.

OTOH, I have personally never seen this on any of my S1 servers which 
all use the serial port.


- <Terje.Mathisen at tmsw.no>
"almost all programming can be viewed as an exercise in caching"

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