Re: [PATCH net-next] net_sched: red: split red_parms into parms and vars
From: Dave Taht <hidden>
Date: 2012-01-06 08:31:47
On Fri, Jan 6, 2012 at 6:47 AM, Eric Dumazet [off-list ref] wrote:
Le jeudi 05 janvier 2012 à 14:39 +0100, Eric Dumazet a écrit :quoted
Problems of RED are : 1) the 'average' on highly variable trafic : It means nothing interesting at all. 2) the idle time management requires to specify the link bandwidth, as a fixed value. This is a problem.A third problem is that ECN marking is performed on the packet we add to the tail of the queue. It's very late... I am currently testing my SFQRED and I try to add ECN in the first packet in queue so that TCP can react faster.
If you are in particular looking for stuff worth marking, vs dropping... you could even look deeper in the queue (group) than the first packet. I am reminded somewhat of how david mills handled the first NSFnet congestion collapse on the fuzzball. http://osdir.com/ml/culture.internet.history/2004-12/msg00003.html "When a new packet arrived and no buffer space was available, the output queues were scanned looking for the biggest elephant (total byte count on all queues from the same IP address) and killed its biggest packet. Gunshots continued until either the arriving packet got shot or there was enough room to save it. It all worked gangbusters and the poor ftpers never found out. "
-- Dave Täht SKYPE: davetaht US Tel: 1-239-829-5608 FR Tel: 0638645374 http://www.bufferbloat.net