Re: bad PPP Performance (with and without IRQTUNE)

D. Chiodo (
Thu, 5 Sep 1996 13:34:23 -0400 (EDT)

The only thing I see that might be relevance is the "USR Sportster"..

I run an ISP, and almost all problems related to getting a connection or
staying connected that our customers have, turn out to be related to the
fact that they have a USR Sportster.. Other customers do not have any

I would stronly suggest taking the USR back where you got it, and getting
something else.

The main decision point would be if your setup had worked previosly with
different kernel/software/libraries/etc.. If this is a new setup, lose the


On Wed, 4 Sep 1996, Michael Neuffer wrote:

> Date: Wed, 4 Sep 1996 12:47:46 +0200 (MET DST)
> From: Michael Neuffer <>
> To:
> Cc:
> Subject: bad PPP Performance (with and without IRQTUNE)
> Hi Mike,
> Would you please forward this to the Linux-kernel list?
> ----------------------------------------------------------------------------
> I am suffering (among other things) from a horrendously slow PPP performance.
> Kernel is 2.0.15 + the last two Linus patches.
> MB is P6/200 board with 64MB RAM, AHA2940U, 2IDE drives, IDE CD, NE2000 clone,
> SB16 clone card (inactive - another issue) and (optionally) a 16550 UART card.
> Symptoms: system is normally lightning FAST. Compiles a complete kernel, on
> an Iomega Jaz drive in about 3-4 minutes (distclean, depend, make, zlilo,
> modules, modules_install).
> PPP is on either Motorola BitSRFR PRO (115,200 on one B channel) or a new USR
> Sportster ``33.6 capable'', again, at 115,200.
> setserial /dev/cua{1,2} spd_vhi is done on both.
> Using CU, either on the built-in UARTs or the external one, serial I/O is FAST.
> Hard to measure but flies on the screen, with the ISDN linke visibly faster.
> Running PPP (pppd 2.2.0f) disconnects two/three times upon dialup from
> either line. Once connection is established, performance is horrendous.
> Typically ftp will do 800 bytes/sec on the ISDN line. Less on the
> modem.
> When downloading a file, one can observe the receive LED on the modem/NT
> to glow steady and bright with a blip in the other direction every 5
> seconds or less. If you abort a transfer, the line remains active for
> 20-30 seconds (way too long).
> Also, while any transfer is occuring, the link is totally dominated by that
> transfer; while FTP, if yoy try to type into a telnet session, the aparent
> baud rate is less than 1. Way to severe.
> The same was confirmed with a P5-90, similarly configured.
> I installed IRQTUNE and followed the directions well. Some improvement in
> throughput was observe; We now can do almost 1KB/sec on a 64Kbps line.
> However, my overpriced P6/200 was transformed into a 386SX, minus the 387,
> running over Starlan; Very very slow everything, even when NO serial traffic
> was evidenced.
> Ethernet traffic on the systems is fine, fast and stable. So it does not
> appear to be an IP problem.
> Any help will be appreciated.
> Please respond to me by email, as I am not in a position to download mailing
> list traffic.
> Thanx, Simon <>