Specifically, I was referring to the pppoe(8) man page where it states (highlights mine):
Code:
Configuring the client involves setting up the configuration file for
ppp(8). The following statements must be included in the file for the
specified system (or ``default'' if no system is specified):
set device "!/usr/sbin/pppoe"
set mtu max 1492
set mru max 1492
set speed sync
disable acfcomp protocomp
deny acfcomp
The set device line tells ppp to use the pppoe program for input and
output instead of using a serial port or other network connection. The
mtu and mru must be set to 1492 to leave room in the outgoing Ethernet
packet for the pppoe headers. The set speed sync line tells ppp to use
synchronous encoding for the packets sent between it and pppoe.
According to RFC 2516, protocol compression, protocomp, is not
recommended, so it is disabled, but not denied. On the other hand,
address and control field compression, acfcomp, must be disabled and
denied.
As I don't use ppp in any form, I can't tell you if your performance problem is due to mru setting or not; only that it was missing from your posted configuration.