Messages in this thread |  | | From | Markus Gutschke <> | Subject | Re: new NTP/PPS patch available | Date | 9 Dec 1996 17:39:10 +0100 |
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"Theodore Y. Ts'o" <tytso@mit.edu> writes: > I'm assuming here that the irq isn't being shared with any other serial > port, and is only being used for the radio clock. In that case, you're > going to be have to read the time from the counter, etc. in any case. > The only question is where you do it. You might as well do it as close > to the beginning of the interrupt processing as possible. > > Note that this is on a per-IRQ basis only! And I think it's reasonable > to assume that you won't be trying to share the serial port with any > other ports, since that's when you get into lots of problems with > variable amounts of time needed to poll several UARTs.
Actually, sharing interrupts is exactly what I do here. Due to lack of free interrupts, my system has an AST 4-port card for its serial lines. As my mainboard's clock is off by several seconds a day, I installed a radio controlled PPS signal that adjusts the system time. I currently use Harald's patches for generating time-stamped events and I installed his "dcf" program for evaluating the data. I do not care very much about absolute accuracy, but I would be very annoyed if the system load was increased because of time-stamping each event on any of my four serial ports. Please consider this application, when designing the new code for the serial ports.
Markus
-- Markus Gutschke Internet: gutschk@math.uni-muenster.de Schlage 5a D-48268 Greven-Gimbte Germany
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