[Codel] [Cerowrt-devel] FQ_Codel lwn draft article review

Toke Høiland-Jørgensen toke at toke.dk
Mon Dec 3 07:54:35 EST 2012

Dave Taht <dave.taht at gmail.com> 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?

Without BQL, exactly how much does the driver queue up? I've heard
someone say 1000 packets for ethernet, but is that in a different
context? E.g. pfifo_fast uses /sys/class/net/*/tx_queue_len for queue
length (I think?), but if the qdisc doesn't, does the driver?


Toke Høiland-Jørgensen
toke at toke.dk
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