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From: "Toke Høiland-Jørgensen" <toke@toke.dk>
To: Dave Taht <dave.taht@gmail.com>
Cc: Jonathan Morton <chromatix99@gmail.com>,
	Cake List <cake@lists.bufferbloat.net>
Subject: Re: [Cake] Lockup at high speeds
Date: Sat, 02 Jun 2018 21:25:35 +0200	[thread overview]
Message-ID: <877enhc7o0.fsf@toke.dk> (raw)
In-Reply-To: <CAA93jw7zybLKTXzGJHb7Hvx1R=ZOzqPL-XJBZ--LMiqrK6bpUQ@mail.gmail.com>

Dave Taht <dave.taht@gmail.com> writes:

> On Sat, Jun 2, 2018 at 11:21 AM, Toke Høiland-Jørgensen <toke@toke.dk> wrote:
>> Dave Taht <dave.taht@gmail.com> writes:
>>
>>> How on earth are you getting these speeds? I'm stuck at a pathetic *4*
>>> gbit here on the admittedly ancient 12 core boxes I'd got.
>>> (I'll go rework my veth topology)
>>
>> Well, having actual hardware do the packet forwarding, and only having
>> each machine process each packet once probably helps...
>>
>>> rcu stuff makes me nervous, what happens if that nat stuff is disabled entirely.
>>>
>>> What if you made q.len and sparse/bullk flow counts atomic ops?
>>
>> The whole qdisc dequeue op is running while holding a global lock. The
>> freezes I'm seeing are happening because the other cores get stuck
>> waiting for the cake dequeue operation to complete (and thus release the
>> qdisc lock). Which is why I suspect an infinite loop somewhere...
>
> Am I wrong in remembering that some qdisc stats are multi-core (like
> qlen?), and summed at some other step?

Well, I *think* you are... :)

> If you pin the card or qdisc to a single core what happens? (Besides
> it getting slower)

No idea. Will try that, once i have more time to debug this; in a few
weeks. I'm trying to get someone else to do something about it in the
meantime, as you can maybe tell ;)

-Toke

  reply	other threads:[~2018-06-02 19:25 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-06-01 17:46 Toke Høiland-Jørgensen
2018-06-01 17:49 ` Jonathan Morton
2018-06-01 17:53   ` Toke Høiland-Jørgensen
2018-06-01 19:03     ` Georgios Amanakis
2018-06-01 19:23       ` Toke Høiland-Jørgensen
     [not found]         ` <9A273CA6-FDF6-485D-B466-8B01D4573BD9@gmail.com>
2018-06-01 19:58           ` Toke Høiland-Jørgensen
2018-06-02 17:08             ` Dave Taht
2018-06-02 18:21               ` Toke Høiland-Jørgensen
2018-06-02 18:55                 ` Dave Taht
2018-06-02 19:25                   ` Toke Høiland-Jørgensen [this message]
2018-06-03 14:56                     ` Georgios Amanakis
2018-06-03 23:26                       ` Toke Høiland-Jørgensen
2018-06-05 11:46                         ` Pete Heist
2018-06-05 14:24                           ` Pete Heist

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