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Hey all,
Just a quick question -- does anyone know what impact the txquelen as displayed by ifconfig
for a nic really has?
I noticed that, with an HTB qdisc installed (which
is what, 128 packets by default?), the txqeuelen is still listed as 100 (ip link
list). As an experiment I set off some downloads, and reduced the txqeuelen to 0
(ifconfig eth0 txqueuelen 0) with no effect at all on the stream.
According to man ifconfig:
txqueuelen
length
Set the length of the transmit queue of the device. It is useful to set this to small values for slower devices with a high latency (modem links, ISDN) to prevent fast bulk transfers from disturbing interactive traffic like telnet too much. Even with the default pfifo_fast qdisc all nics
start with, reducing or setting the txqueuelen to 0 seems to have no
effect. Should it be having an impact, and if not, then why is it
there?
I'm optimising a link for certain streams, and
using a pfifo with limit 25 on one of the classes. Wondering if any
latency saved here is going to be lost further up the chain.
Regards,
Ashton
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