A damp discussion of network queuing

Posted Oct 17, 2014 9:53 UTC (Fri) by paulj (subscriber, #341)
Parent article: A damp discussion of network queuing

Note, jg didn't quite discover buffer-bloat. It had been researched and reasonably well described in academia. There were even a string of papers on the benefits of "tiny buffers". However, that work somehow got stuck in academia and was never communicated to the wider engineering networking world. What jg has done is, I guess, to have discovered it for that engineering world and communicate the previous results on, and then develop that knowledge further.

I believe jg has explained that on LWN before, e.g. see comments in http://lwn.net/Articles/418918/ .

A damp discussion of network queuing

Posted Oct 20, 2014 7:55 UTC (Mon) by marcH (subscriber, #57642) [Link] (4 responses)

Among others, I reported TxDescriptors bufferbloat to "engineering" in 2004:

http://thread.gmane.org/gmane.linux.network/6366/focus=11785
http://marc.info/?l=linux-netdev&m=108462579501312
http://oss.sgi.com/archives/netdev/2004-06/msg00917.html

However I think this got eventually lost in the "agitation of life"; unlike jg I had neither fame nor a very catchy name for it :-)

---

(Good) words are incredibly important, it's funny how so many engineers don't realize they make all the difference.

http://martinfowler.com/bliki/TwoHardThings.html

A damp discussion of network queuing

Posted Oct 20, 2014 8:18 UTC (Mon) by paulj (subscriber, #341) [Link] (3 responses)

Ah kudos for pointing it out.

It's amazing that the default txqueuelen got bumped up to 1000 for all interfaces. It's even more amazing that this is *still* the default, even on wifi devices 10 years later. :(

1000 packet queues are just insane, even on high-speed links.

I've had "for H in <list of devices> ; do ip link set dev $H qlen 5; done" in my rc.local for quite a while. Unfortunately though it doesn't apply to devices brought up post-boot by, e.g., NetworkManager. I havn't yet looked into how to make NM set the qlen.

A damp discussion of network queuing

Posted Oct 23, 2014 2:54 UTC (Thu) by dcbw (guest, #50562) [Link] (2 responses)

A dispatcher script would do it, for an 'up' even take the interface name and run /sbin/ip to set the qlen. Examples here, drop it into /etc/NetworkManager/dispatcher.d/ and chmod 700.

http://cgit.freedesktop.org/NetworkManager/NetworkManager...

more information in 'man NetworkManager'.

A damp discussion of network queuing

Posted Dec 1, 2014 20:57 UTC (Mon) by paulj (subscriber, #341) [Link]

That looks like it should what I want. Thanks! :)

A damp discussion of network queuing

Posted Dec 1, 2014 22:51 UTC (Mon) by paulj (subscriber, #341) [Link]

Submitted a NetworkManager script to set txqueuelen according to nmcli's SPEED.CAPABILITIES value on interface up, as RedHat bug #1169529:

https://bugzilla.redhat.com/show_bug.cgi?id=1169529