[LibreQoS] In BPF pping - so far

Robert Chacón robert.chacon at jackrabbitwireless.com
Sat Oct 15 22:26:32 EDT 2022

Hey Herbert,

Wow. Awesome work! How exciting. We may finally get highly scalable TCP
latency tracking in LibreQoS and BracketQoS.
Regarding how we receive the data, I suppose whatever is most efficient and
scalable for networks with high subscriber counts.
In v1.1 we were just parsing some data from the console output:

   - rtt1
   - IP address 1
   - IP address 2

I am a big fan of having some sort of JSON structure to pull info from.
What do you recommend here for optimal efficiency?


On Sat, Oct 15, 2022 at 7:59 PM Herbert Wolverson via LibreQoS <
libreqos at lists.bufferbloat.net> wrote:

> Hey,
> I've had some pretty good success with merging xdp-pping (
> https://github.com/xdp-project/bpf-examples/blob/master/pping/pping.h )
> into xdp-cpumap-tc ( https://github.com/xdp-project/xdp-cpumap-tc ).
> I ported over most of the xdp-pping code, and then changed the entry point
> and packet parsing code to make use of the work already done in
> xdp-cpumap-tc (it's already parsed a big chunk of the packet, no need to do
> it twice). Then I switched the maps to per-cpu maps, and had to pin them -
> otherwise the two tc instances don't properly share data. Right now, output
> is just stubbed - I've still got to port the perfmap output code. Instead,
> I'm dumping a bunch of extra data to the kernel debug pipe, so I can see
> roughly what the output would look like.
> With debug enabled and just logging I'm now getting about 4.9 Gbits/sec on
> single-stream iperf between two VMs (with a shaper VM in the middle). :-)
> So my question: how would you prefer to receive this data? I'll have to
> write a daemon that provides userspace control (periodic cleanup as well as
> reading the performance stream), so the world's kinda our oyster. I can
> stick to Kathie's original format (and dump it to a named pipe, perhaps?),
> a condensed format that only shows what you want to use, an efficient
> binary format if you feel like parsing that...
> (I'll post some code soon, getting sleepy)
> Thanks,
> Herbert
> _______________________________________________
> LibreQoS mailing list
> LibreQoS at lists.bufferbloat.net
> https://lists.bufferbloat.net/listinfo/libreqos

Robert Chacón
CEO | JackRabbit Wireless LLC <http://jackrabbitwireless.com>
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