[Cerowrt-devel] BBR congestion control algorithm for TCP in net-next
woody77 at gmail.com
Mon Sep 26 15:45:15 EDT 2016
Thanks! And sorry that I missed the sample code in the patch.
On Mon, Sep 26, 2016 at 12:30 Neal Cardwell <ncardwell at google.com> wrote:
> On Mon, Sep 26, 2016 at 2:47 PM, Aaron Wood <woody77 at gmail.com> wrote:
> > Dumb question on this: The tcp_bbr_info struct for a socket can be
> > inspected at runtime through the ss utility or through a get socket opts
> > call, right?
> Yes, you can use either approach:
> (1) from code you can use TCP_CC_INFO socket option; there is sample
> code in the original kernel patch for TCP_CC_INFO:
> (2) from ss: if you download and build the net-next branch of the
> iproute2 package:
> then you will get support to print out the main parameters for a BBR
> connection, eg:
> The patch with BBR support for ss is here:
> As the commit notes, the BBR output looks like:
> Hope that helps,
> > -Aaron
> > On Sat, Sep 17, 2016 at 11:34 AM, Maciej Soltysiak <maciej at soltysiak.com
> > wrote:
> >> Hi,
> >> Just saw this: https://patchwork.ozlabs.org/patch/671069/
> >> Interested to see how BBR would play out with things like fq_codel or
> >> cake.
> >> "loss-based congestion control is unfortunately out-dated in today's
> >> networks. On
> >> today's Internet, loss-based congestion control causes the infamous
> >> bufferbloat problem"
> >> So, instead of waiting for packet loss they probe and measure, e.g. when
> >> doing slow start (here called STARTUP) they don't speed up until packet
> >> loss, but slow down before reaching estimated bandwidth level.
> >> Cake and fq_codel work on all packets and aim to signal packet loss
> >> to network stacks by dropping; BBR works on TCP and aims to prevent
> >> loss.
> >> Best regards,
> >> Maciej
> >> _______________________________________________
> >> Cerowrt-devel mailing list
> >> Cerowrt-devel at lists.bufferbloat.net
> >> https://lists.bufferbloat.net/listinfo/cerowrt-devel
> > _______________________________________________
> > Cerowrt-devel mailing list
> > Cerowrt-devel at lists.bufferbloat.net
> > https://lists.bufferbloat.net/listinfo/cerowrt-devel
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