[Codel] fq_codel_drop vs a udp flood

[Dave Taht]

On Tue, May 3, 2016 at 10:54 AM, Eric Dumazet <eric.dumazet at gmail.com> wrote:
> On Tue, 2016-05-03 at 10:37 -0700, Dave Taht wrote:
>> Thus far this batch drop patch is testing out beautifully. Under a
>> 900Mbit flood going into 100Mbit on the pcengines apu2,  cpu usage for
>> ksoftirqd now doesn't crack 10%, where before (under
>> pie,pfifo,fq_codel,cake & the prior fq_codel) it went to 88% and
>> ultimately bad things happened, like losing routability.
>>
>> I've had it running for hours and I hardly notice it's there.
>>
>
> Excellent, thanks for testing it.

Getting it up to 4 floods with 8k udp fragments each could take it up
to about 20-30% of cpu.

iperf3 -c 172.26.64.200 -u -P 4 -b200Mbit -t 600 &

still, beyond awesome.

>
>> Performance for the normal cc controlled and/or sparse flows is
>> unaffected, aside from the uncontrolled flows eating their percentage
>> of the link.
>>
>> Nice work. Thx. This should go into -stable.
>>
>> https://patchwork.ozlabs.org/patch/617307/
>>
>> Sigh. The RFC is past last call...
>
> It is merged :
>
> https://git.kernel.org/cgit/linux/kernel/git/davem/net-next.git/commit/?id=9d18562a227874289fda8ca5d117d8f503f1dcca

the ietf approval process is about 17512 hours longer than the netdev
approval process.

>
>



-- 
Dave Täht
Let's go make home routers and wifi faster! With better software!
http://blog.cerowrt.org