On Mon, 24 Feb 1997, Bartholomew Niswonger wrote:

> > Did anybody else notice that put is about half the speed of get when
> > doing ftp transfers?
>
> I notice the same behavior with 1.1 & an i486DX4/133 over ppp (though
> I dont get anywhere near 2.2 Mb/sec)

In the case of a ppp link and the port-i386, this behavior is related to
the poor com driver and too-small buffers in the tty subsystem. At high or
even high-ish speeds, one or two outgoing bytes of data are dropped
whenever the modem asserts flow control, causing lots of outgoing
packets to disappear because of failed checksums. Unlike the other
problems with serial devices, this one doesn't require fancy modifications
to the com driver. Try:

sys/kern/tty.c: change 3 clalloc()s in ttymalloc() to 4k.
sys/sys/tty.h: change TTYHOG to 4k.

And, if your system is like mine, these problems will disappear. 

Presumably this has nothing to do with Matthias' problems, which appear on
a real network device.

nath