[Make-wifi-fast] [Codel] fq_codel_drop vs a udp flood
leroi.lists at gmail.com
Mon May 2 10:09:48 EDT 2016
On 1 May 2016 at 20:59, Eric Dumazet <eric.dumazet at gmail.com> wrote:
> On Sat, 2016-04-30 at 20:41 -0700, Dave Taht wrote:
>> >>> 45.78% [kernel] [k] fq_codel_drop
>> >>> 3.05% [kernel] [k] ag71xx_poll
>> >>> 2.18% [kernel] [k] skb_release_data
>> >>> 2.01% [kernel] [k] r4k_dma_cache_inv
>> The udp flood behavior is not "weird". The test is wrong. It is so filling
>> the local queue as to dramatically exceed the bandwidth on the link.
> Well, just _kill_ the offender, instead of trying to be gentle.
> fq_codel_drop() could drop _all_ packets of the fat flow, instead of a
> single one.
> It is too cpu intensive to be kind to the elephant, since under pressure
> fq_codel_drop() needs to be called for every enqueue.
> Really, we should not try to let inelastic flows hurt us.
> I can provide a patch.
So if I run some UDP download you will just kill me? Sounds broken.
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