silo overflows and ppp ierrs

[Jim Rees <rees@umich.edu>]

I get terrible ppp performance on my 486 running 2.2.  The line is at 57600,
with a 550 uart and a 38.4 modem.  I'm getting way more ppp errors than silo
overflows:

pccom1 at isa0 port 0x2f8-0x2ff irq 3: ns16550a, working fifo
pccom1: 14 silo overflows

ooty# netstat -i
Name    Mtu   Network     Address              Ipkts Ierrs    Opkts Oerrs  Coll
ppp0    1500  <Link>                           48964  2523    50733     0     0

The other side is a Pentium running the same kernel, and it seems to be ok:

% netstat -i
Name    Mtu   Network     Address              Ipkts Ierrs    Opkts Oerrs  Coll
ppp0    1500  <Link>                            2654     2     2485     0     0

Am I doing something wrong?  Shouldn't a 486 be able to keep up?