Hi, a class is starved only if those with higher priority are always (of pretty often) backlogged and do not give the lower priority classes a chance to transmit. Therefore, if you transmit at a rate smaller than your CPU/s and NIC/s can handle you will not experience any starving. For example, if you generate 50Mbit traffic on a 100Mbit NIC it is likely that you won't see any starving (unless your system is not able to handle 50Mbit traffic because of a complex TC or iptables configuration that consumes lot of CPU). Regards /Christian [ http://benve.info ] On Fri, 2007-06-15 at 15:46 +0800, Salim S I wrote: > Slightly offtopic... Has anyone really experienced starving of low > priority traffic with PRIO qdisc? > In my setup, I never achieved that, though I also wanted exactly that > situation. I gave both the classes same amount of traffic at the same > time. High prio got more bandwidth, but no starvation, even after I sent > more traffic than the link capacity. > > > -----Original Message----- > > From: lartc-bounces@xxxxxxxxxxxxxxx > [mailto:lartc-bounces@xxxxxxxxxxxxxxx] > > On Behalf Of Christian Benvenuti > > Sent: Friday, June 15, 2007 3:32 PM > > To: lartc@xxxxxxxxxxxxxxx > > Subject: Re: PQ questions > > > > Hi, > > > > > > Your config does not prevent an higher priority class from > starving > > > > a lower priority class. > > > > > > Exactly. That is requirement. > > > > OK > > > > > Those stats are nice to have, but the ones I must have are for how > many > > > bytes/packets are enqueued at whatever time I check the queues. > > > > That information is there. Here is an example: > > (b=bytes p=packets) > > > > #tc -s -d qdisc list dev eth1 > > > > qdisc prio 1: root bands 3 priomap 1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1 > > Sent 85357186 bytes 59299 pkt (dropped 0, overlimits 0 requeues 0) > > rate 0bit 0pps backlog 0b 35p requeues 0 > > +-> This field is not initialized for this > > qdisc type > > qdisc pfifo 10: parent 1:1 limit 1000p > > Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0) > > rate 0bit 0pps backlog 0b 0p requeues 0 > > ^^^^^^^^^^^^^ > > qdisc pfifo 20: parent 1:2 limit 1000p > > Sent 85357120 bytes 59298 pkt (dropped 0, overlimits 0 requeues 0) > > rate 0bit 0pps backlog 50470b 35p requeues 0 > > ^^^^^^^^^^^^^^^^^^ > > qdisc pfifo 30: parent 1:3 limit 1000p > > Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0) > > rate 0bit 0pps backlog 0b 0p requeues 0 > > ^^^^^^^^^^^^^ > > > > > I have tried to configure PQ to have two queues per filter with no > > success. > > > > What do you mean? > > > > > Is it even possible to have (what I'll call) hierarchical PQ? I have > yet > > to > > > find it. > > > > Something like this? > > > > tc qdisc add dev eth1 handle 1: root prio > > tc qdisc add dev eth1 parent 1:1 handle 10 prio > > tc qdisc add dev eth1 parent 1:2 handle 20 prio > > tc qdisc add dev eth1 parent 1:3 handle 30 prio > > > > Regards > > /Christian > > [ http://benve.info ] _______________________________________________ LARTC mailing list LARTC@xxxxxxxxxxxxxxx http://mailman.ds9a.nl/cgi-bin/mailman/listinfo/lartc
