On Mon, 2012-12-03 at 06:58 -0800, Paul E. McKenney wrote: > On Mon, Dec 03, 2012 at 01:54:35PM +0100, Toke Høiland-Jørgensen wrote: > > Dave Taht <[email protected]> writes: > > > > > you have no control. The tx queue rings are flooded before control is > > > handed back to the fq_codel scheduler. You can get some control back > > > on a non-BQL driver by reducing the number of tx descriptors > > > dramatically, but that leads to issues with small vs big packets.... > > > > Right, so BQL is pretty much a requirement to get anything worthwhile > > out of fq_codel? Or is that too strongly put? > > If I understand the code correctly, without BQL, FQ-CoDel does not get > invoked at all. > >
It depends on many factors. You can setup a qdisc hierarchy of on HTB/TBF and one fq_codel. Egress rate limiting is a good way to permit to build a queue in qdisc (in fq_codel) BQL in itself avoids a too large queue on the device driver, thats only a part of the problem. If your setup is a computer with 1Gbps ethernet link, and a home router with a 1Mbps upstream link that you cant access (ie install fq_codel on it), BQL on the 1Gbps link wont help in itself. It will still allow your computer to send 1Gbps worth of data that will build a huge queue on the home router. One way to handle that is using rate limiting to not create a queue on the router. _______________________________________________ Cerowrt-devel mailing list [email protected] https://lists.bufferbloat.net/listinfo/cerowrt-devel
