Questioning altq (cbq) performance above 4Mb on gif or above 40 Mb on e1000

[Ermal Luçi]

On Fri, Nov 5, 2010 at 1:33 AM, Ricky  Charlet <RCharlet at adaranet.com> wrote:
> Has anyone out there run altq with cbq with bandwidth limits set around 40 ~ 50 Mb and seen it work well (actual through put allowed to come near that speed)?
>
> Thanks
> ---
> Ricky Charlet
> Adara Networks
> USA 408-433-4942
>

I can suggest to try with higher hz and increase queue lengths in altq.
By default they are 50 which is quite low in that regard.

>
>> -----Original Message-----
>> From: owner-freebsd-pf at freebsd.org [mailto:owner-freebsd-
>> pf at freebsd.org] On Behalf Of Ricky Charlet
>> Sent: Wednesday, November 03, 2010 9:47 PM
>> To: 'freebsd-pf at freebsd.org'; 'altq at csl.sony.co.jp'
>> Subject: Questioning altq (cbq) performance above 4Mb on gif or above
>> 40 Mb on e1000
>>
>> Howdy,
>>
>> (FreeBsd 8.0REL plus a modified e1000 driver borrowing the 8.1 altq
>> capabilities, amd64, 8 core)
>>
>>         I have been measuring altq performance on my system. I set a
>> cbq bandwith limit for a queue, match traffic to the queue with an
>> appropriate rule and pump data.
>>
>>         Without altq enabled, my traffic gen tool (nuttcp) can pump
>> 800Mb across my gig links.
>>
>>         With altq(cbq) setting bandwith limits (no borrow), up to about
>> 40Mb on em0 altq keeps up. But from 40Mb bandwith limit and up, altq
>> seems to slow down my traffic much slower than the bandwidth limits.
>>
>>         Same effect is observed on gif interfaces (where my real
>> interest lies) but much worse. With altq(cbq) setting bandwith limits
>> (no borrow), up to about 4Mb on gif0 altq keeps up. But from 4Mb
>> bandwidth limit and up, altq seems to slow down my traffic much lower
>> than the bandwidth limits.
>>
>>         I have a large file of sample data in excel formant which I'd
>> like to share. Is there an appropriate way to share it with this list?
>>
>>         I know I'm not cpu bound (97% idle while nuttcp pushes 800Mb
>> traffic and altq configured with a bandwidth limit of 50Mb actually
>> passes 30Mb.)
>>
>>         I sort of suspect I'm mutex bound but have no idea how to test
>> that.
>>
>>
>>
>>  (1) this config allows about 4Mb tcp traffic to pass:
>> ----------cut------------------
>> altq on em0 cbq bandwidth 100Mb queue { queue1, queue2 }
>> queue queue1  bandwidth 1Mb priority 7 cbq  (default)
>> queue queue2 bandwidth 50Mb priority 1 cbq
>> pass out quick on gif10 inet proto tcp no state queue queue2
>> pass out quick on gif10 proto icmp queue queue2
>> ----------paste----------------
>>
>> (2) this config allows about 40 Mb tcp traffic to pass
>> ----------cut------------------
>> altq on em0 cbq bandwidth 100Mb queue { queue1, queue2 }
>> queue queue1  bandwidth 1Mb priority 7 cbq  (default)
>> queue queue2 bandwidth 50Mb priority 1 cbq
>> pass out quick on em0 inet proto tcp no state queue queue2
>> pass out quick on em0 proto icmp queue queue2
>> ----------paste----------------
>>
>>         Yes, I send appropriate traffic in each case to be 'caught' by
>> the tcp pass out rule wether it be found on a gif or an em.
>>
>>
>>         My goal is to get 'expected' behavior (a bandwidth limit of 40
>> Mb allows 40Mb to pass) at T3 link speed (45Mb). Is this a reasonable
>> expectation? Any ideas about config jigs or tests to run?
>>
>>
>>
>> ---
>> Ricky Charlet
>> Adara Networks
>> USA 408-433-4942
>>
>>
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-- 
Ermal