Messages in this thread | | | Subject | Re: 2.0.30 serial.c, ppp.c and pppd-2.2 questions | Date | Tue, 22 Jul 1997 21:59:19 +0200 (MET DST) | From | (Rogier Wolff) |
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Theodore Y. Ts'o wrote:
> Rob, what else do you have on your system? Although I haven't done the > test in a while, the serial driver was originally written to be able to > support 115kbaud on a 386/40. (Granted this was a kermit transfers, not > PPP; but it was a looped back 115kbaud transfer where the transmitting > and receiving ports were on the same CPU, doubling the work.)
This is a bad test. Why? Because if the recieving end stops working for a tenth of a second, the transmitting end will too. No overruns/anything.
My Specialix card also loops back just fine at 115k. It just doesn't talk to a modem at 115k. This time it's probably a baud-rate incompatibility: The specialix card can only do 111k6 due to "clock divider" issues.
> The fact that your 486/66 isn't keeping up makes me wonder what other > sources of interrupts you are having on your system.
I too have a 486/66, this time the serial ports are on a specialix card, not the standard serial ports. The flip buffers overflow when I get the machine paging heavily. It'll be doing a few hundred IDE interrupts per second around that time.....
The specialix has an 8byte FIFO, interrupt theshold is set at 6. I seem to have overrun reporting on this thing turned off. But wouldn't ppp report bad packets if that happened?
% cat /proc/net/dev Inter-| Receive | Transmit face |packets errs drop fifo frame|packets errs drop fifo colls carrier ppp0: 1488 0 0 0 0 1387 0 0 0 0 0
Alas, the counters probably get reset on every session, and I didn't get any flip buffer overrun last session.
Roger.
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