[Bloat] BBR implementations, knobs to turn?

[Luca Muscariello]

Hi Erick,

one question about the PGW: is it a policer or a shaper that you have
installed?
Also, have you tried to run a ping session before and in parallel to the
curl sessions?

Luca



On Thu, Nov 19, 2020 at 2:15 PM <erik.taraldsen at telenor.com> wrote:

> Update:
> The 5G router was connected to a new base station.  Now the limiting
> factor of throughput is the policer on the PGW in mobile core, not the
> radio link itself.  The SIM card used is limited to 30Mbit/s.  This
> scenario favours the new server.  I have attached graphs comparing radio
> link limited vs PGW policer results, and a zoomed in graph of the policer
>
>
> We have Huawei RAN and Ericsson RAN, rate limited and not rate limited
> subscriptions, 4G and 5G access, and we are migrating to a new core with
> new PGW (policer).  Starting to be a bit of a matrix to set up tests for.
>
>
> -Erik
>
>
> ________________________________________
> Fra: Jesper Dangaard Brouer <brouer at redhat.com>
> Sendt: 17. november 2020 16:07
> Til: Taraldsen Erik; Priyaranjan Jha
> Kopi: brouer at redhat.com; ncardwell at google.com; bloat at lists.bufferbloat.net
> Emne: Re: [Bloat] BBR implementations, knobs to turn?
>
> On Tue, 17 Nov 2020 10:05:24 +0000 <erik.taraldsen at telenor.com> wrote:
>
> > Thank you for the response Neal
>
> Yes. And it is impressive how many highly qualified people are on the
> bufferbloat list.
>
> > old_hw # uname -r
> > 5.3.0-64-generic
> > (Ubuntu 19.10 on xenon workstation, integrated network card, 1Gbit
> > GPON access.  Used as proof of concept from the lab at work)
> >
> >
> > new_hw # uname -r
> > 4.18.0-193.19.1.el8_2.x86_64
> > (Centos 8.2 on xenon rack server, discrete 10Gbit network card,
> > 40Gbit server farm link (low utilization on link), intended as fully
> > supported and run service.  Not possible to have newer kernel and
> > still get service agreement in my organization)
>
> Let me help out here.  The CentOS/RHEL8 kernels have a huge amount of
> backports.  I've attached a patch/diff of net/ipv4/tcp_bbr.c changes
> missing in RHEL8.
>
> It looks like these patches are missing in CentOS/RHEL8:
>  [1] https://git.kernel.org/torvalds/c/78dc70ebaa38aa3
>  [2] https://git.kernel.org/torvalds/c/a87c83d5ee25cf7
>
> Could missing patch [1] result in the issue Erik is seeing?
> (It explicitly mentions improvements for WiFi...)
>
> --
> Best regards,
>   Jesper Dangaard Brouer
>   MSc.CS, Principal Kernel Engineer at Red Hat
>   LinkedIn: http://www.linkedin.com/in/brouer
> _______________________________________________
> Bloat mailing list
> Bloat at lists.bufferbloat.net
> https://lists.bufferbloat.net/listinfo/bloat
>
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