Poor PPP performance in 2.2.x

Stephen Foskett (sfoskett@slf.gweep.net)
Tue, 02 Feb 1999 11:32:59 -0600

There was some discussion of poor PPP performance in the 2.2.x kernels here
last week. The suggested solution was to disable DMA on the hard disk.

I have a Toshiba Portege 3015CT running Debian Slink. I compiled the 2.2.0
and 2.2.1 kernels and they run great... EXCEPT that I still have the PPP
problem. This machine does have a UDMA hard disk, so I tried disabling DMA
on the disk. This did not fix the problem. I tried the other settings
with hdparm, too, turning everything off and leaving the readahead at just
2. This did not help at all. I recompiled the kernel to not automatically
turn on DMA as well. The next step would be to disable DMA entirely in the
kernel, I suppose, but it doesn't look like this DMA thing is the answer,
at least for me.

Has anyone got another idea? I am getting the same bytes in the log from
pppd as described previously. I too am seeing lots of errors with "netstat
ppp0". This all worked find with 2.1.125 and 2.0.36. Is it a problem with
pppd? With pcmcia? With the kernel?

Thanks for any suggestions,
Stephen

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