[Bloat] Fwd: Traffic shaping at 10~300mbps at a 10Gbps link

[Rich Brown <richb.hanover@gmail.com>]

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Saw this on the lartc mailing list... For my own information, does anyone have thoughts, esp. for this quote:

"... when the speed comes to about 4.5Gbps download (upload is about 500mbps), chaos kicks in. CPU load goes sky high (all 24x2.4Ghz physical cores above 90% - 48x2.4Ghz if count that virtualization is on)..."

Thanks.

Rich


> Begin forwarded message:
> 
> From: "Ethy H. Brito" <ethy.brito@inexo.com.br>
> Subject: Traffic shaping at 10~300mbps at a 10Gbps link
> Date: June 7, 2021 at 12:38:53 PM EDT
> To: lartc <lartc@vger.kernel.org>
> 
> 
> Hi
> 
> I am having a hard time trying to shape 3000 users at ceil speeds from 10 to 300mbps in a 7/7Gbps link using HTB+SFQ+TC(filter by IP hashkey mask) for a few days now tweaking HTB and SFQ parameters with no luck so far.
> 
> Everything seems right, up 4Gbps overall download speed with shaping on.
> I have no significant packets delay, no dropped packets and no high CPU average loads (not more than 20% - htop info)
> 
> But when the speed comes to about 4.5Gbps download (upload is about 500mbps), chaos kicks in.
> CPU load goes sky high (all 24x2.4Ghz physical cores above 90% - 48x2.4Ghz if count that virtualization is on) and as a consequence packets are dropped (as reported by tc -s class sh ...), RTT goes above 200ms and a lots of ungry users. This goes from about 7PM to 11 PM every day.
> 
> If I turn shaping off, everything return to normality immediately and peaks of not more than 5Gbps (1 second average) are observed and a CPU load of about 5%. So I infer the uplink is not crowded.
> 
> I use one root HTB qdisc and one root (1:) HTB class.
> Then about 20~30 same level (1:xx) inner classes to (sort of) separate the users by region 
> And under these inner classes, goes the almost 3000 leaves (1:xxxx). 
> I have one class with about 900 users and this quantity decreases by the other inner classes having some of them with just one user.
> 
> Is the way I'm using HTB+SFQ+TC suitable for this job?
> 
> Since the script that creates the shaping environment is too long I do not post it here.
> 
> What can I inform you guys to help me solve this?
> Fragments of code, stats, some measurements? What?
> 
> Thanks.
> 
> Regards
> 
> Ethy


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