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

[Ricky Charlet]

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




> -----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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