Article View: comp.os.linux.misc
Article #563Re: Slow Performance froma "Fast Serial Card"?
From: Chris
Date: Tue, 25 Mar 1997 00:00
Date: Tue, 25 Mar 1997 00:00
50 lines
3166 bytes
3166 bytes
Nils Faerber wrote:
>
> fwtk@niw.cerberus.navy.gov.au wrote:
> : Can anyone offer me some pointers on this one please?
> I hope so ...
>
> : I am using a Linux box as an Internet gateway for a LAN and some dial-in
> : lines. The box has two internal 14.4kbps modems and one external 28.8
> : kbps modem. Two lines are for dialling in and on to dial out to the
> : ISP.
> : If I use one of the 14.4 kbps modems to dial the ISP I get a download
> : speed of around 1000-1300 bytes/sec. I think this is pretty
> : reasonable. However, when I try to use the 28.8 kbps modem to dial the
> : ISP (preferable) the download speed drops to between 100-200 bytes/sec!
> : ie, about 10 times SLOWER :-(
> : I think it must be the serial card, but it is a new serial card with
> : 16550 UARTS. I have tried configuring it at boot time with:
> This sounds like an interrupt conflict to me. More than two serial ports, and
> an internal modem is a serial port, are always difficult (there recently was
> a thread about this somewhere in comp.os.linux.* land). So check your
> interrupt settings. If you use standard settings you will probably have
> ttyS0 IRQ 4
> ttyS1 IRQ 3
> ttyS2 IRQ 4 (!!!)
> Most PC cards are not designed to share interrupts, but it is possible
> though. If you can avoid shared interrupt whereever possible.
You might also want to make sure you're running
'setserial' at boot time. I've got 4 serial ports,
at IRQ 4, 3, 7, and 11. Even though they're all
on separate IRQs I was getting miserable results
until I ran setserial set to autoprobe everything
in my /etc/rc.d files (slackware distribution).
Once setserial ran everything was peachy-keen.
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X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 1103af,d120540d33c72067 X-Google-Attributes: gid1103af,public X-Google-Thread: f9b51,d120540d33c72067 X-Google-Attributes: gidf9b51,public X-Google-Thread: 10669a,d120540d33c72067 X-Google-Attributes: gid10669a,public X-Google-Thread: 102983,d120540d33c72067 X-Google-Attributes: gid102983,public From: Chris <harshman@paradigm.uor.edu> Subject: Re: Slow Performance froma "Fast Serial Card"? Date: 1997/03/25 Message-ID: <33383F2A.52803703@paradigm.uor.edu> X-Deja-AN: 228691746 References: <33308CB0.170C@niw.cerberus.navy.gov.au> <5h0noc$1su@asgard.si.sub.de> Organization: Enterprise for Economic Excellence Newsgroups: comp.os.linux.misc,comp.os.linux.networking,comp.os.linux.setup,aus.computers.linux