Date: Thu, 16 Nov 1995 13:28:12 +1100 From: Bruce Evans <bde@zeta.org.au> To: bde@zeta.org.au, hsu@cs.hut.fi Cc: current@FreeBSD.ORG, j@uriah.heep.sax.de Subject: Re: ISP state their FreeBSD concerns Message-ID: <199511160228.NAA29871@godzilla.zeta.org.au>
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>Could it be sensible to make RS_IBUFSIZE ((TTYHOG)/4) ? This would allow >tuning TTYHOG value only. It would be a kludge, though. Maybe serial Not very. RS_IBUFSIZE is the fundamental quantity. It should depend on the driver and on the line speed and TTYHOG should depend on RS_IBUFSIZE and the system load. All the values should be variables but there has to be some limit to stop unread input filling up all of memory. > > RS_IBUFSIZE - 11520 * (1.0/hz + max_softtty_interrupt_latency) >= 0 >Btw, lots of ISDN "modems" like ZyXEL's are connected with overclocked >16650/16550 serial ports. I have one at 460.8k. Does it have a higher clock speed or extra clocks? Extra clocks aren't supported (just as well they aren't as necessary as extra video clocks) and you would have to increase various constants for flow control to work and for good performance (output buffer sizes are a bit low but can't be increased much because some of the buffers are on the kernel stack...). Bruce
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