Thanks for the pointers, Bob. best regards, neal
On Mon, Aug 29, 2022 at 12:47 PM 'Bob McMahon' via BBR Development < [email protected]> wrote: > Thanks Neal. You might want to check out the flows released as iperf 2. > <https://sourceforge.net/p/iperf2/code/ci/master/tree/flows/> Basically > instantiate flows and run them. There typically is a controller running > python3 (v 3.10 or better) that uses ssh pipes to DUTs. The design is event > driven <https://en.wikipedia.org/wiki/Event-driven_programming> and > utilizes python's asyncio <https://docs.python.org/3/library/asyncio.html> > which is quite powerful. The DUTs just need iperf2 and ssh. > > The code is at an alpha level and we're looking for broader industry > support and contributions. Both in realtime plotting but also in things > like multivariate regression detection using statistical process controls > (SPC) e.g. Hoteling > <https://www.itl.nist.gov/div898/handbook/pmc/section3/pmc341.htm>. There > is some crude clustering code around latency too which uses > Kolmogorov-Smirnov > <https://en.wikipedia.org/wiki/Kolmogorov%E2%80%93Smirnov_test>distance > matrices per the histograms. > > A suggestion is that those in developer and control test roles synchronize > their device clocks with PTP. Iperf 2 supports one way delay (OWD) > calculations but these only work if the clocks are sync'd. These in turn > can be used per Little's law > <https://en.wikipedia.org/wiki/Little%27s_law> to calculate effective > average queue depth, though this typically assumes a steady state > measurement. > > Bob > > On Sun, Aug 28, 2022 at 4:54 PM Neal Cardwell <[email protected]> > wrote: > >> If you are talking about the screenshot of the UI at >> https://github.com/google/transperf, yes, that particular test is a >> simple bulk flow test to show a simple case to give a sense of what the UI >> looks like. :-) >> >> We use a few different approaches that can examine dynamic flows causing >> packet loss: >> >> (1) The test configuration language is Python, so you can construct >> arbitrarily fancy dynamic flow scenarios with arbitrary numbers of flows >> starting and stopping at arbitrary times. >> >> (2) The tests can also use netperf command line options to run periodic >> short transfers. (And we welcome patches to integrate support for other >> tools.) >> >> (3) We also run a fair number of tests for robustness to loss just using >> randomly injected packet loss (using netem). >> >> These are just some of the approaches we have used, and I don't claim >> that these are the only or best approaches to look at this. :-) >> >> cheers, >> neal >> >> >> On Sun, Aug 28, 2022 at 6:39 PM Bob McMahon <[email protected]> >> wrote: >> >>> Hi Neal, >>> >>> These look like steady-state bulk flow tests unless I'm missing >>> something. >>> >>> Bob >>> >>> On Sun, Aug 28, 2022 at 11:43 AM Neal Cardwell <[email protected]> >>> wrote: >>> >>>> Sure. For testing these kinds of properties of the BBR algorithm we use >>>> various transperf test cases. The transperf tool is something Soheil Hassas >>>> Yeganeh and our team cooked up and open-sourced here: >>>> >>>> https://github.com/google/transperf >>>> >>>> Best regards, >>>> neal >>>> >>>> On Sat, Aug 27, 2022, 4:43 PM Bob McMahon <[email protected]> >>>> wrote: >>>> >>>>> Curious to what you're doing during development, if you can share? >>>>> >>>>> Thanks, >>>>> Bob >>>>> >>>>> On Sat, Aug 27, 2022 at 7:44 AM Neal Cardwell <[email protected]> >>>>> wrote: >>>>> >>>>>> Hi Bob, >>>>>> >>>>>> Good question. I can imagine a number of different techniques to >>>>>> generate and measure the traffic flows for this kind of study, and don't >>>>>> have any particular suggestions. >>>>>> >>>>>> neal >>>>>> >>>>>> >>>>>> On Fri, Aug 26, 2022 at 4:54 PM Bob McMahon <[email protected]> >>>>>> wrote: >>>>>> >>>>>>> Hi Neal, >>>>>>> >>>>>>> Any thoughts on tooling to generate and measure the traffic flows >>>>>>> BBR is designed to optimize? I've been adding some low duty cycle >>>>>>> support >>>>>>> in iperf 2 <https://sourceforge.net/projects/iperf2/> with things >>>>>>> like --bounceback and --burst-period and --burst-period >>>>>>> <https://iperf2.sourceforge.io/iperf-manpage.html>. We could pull >>>>>>> the size and period from a known distribution or distributions though >>>>>>> not >>>>>>> sure what to pick. >>>>>>> >>>>>>> Thanks, >>>>>>> Bob >>>>>>> >>>>>>> Bob >>>>>>> >>>>>>> On Fri, Aug 26, 2022 at 6:36 AM 'Neal Cardwell' via BBR Development < >>>>>>> [email protected]> wrote: >>>>>>> >>>>>>>> Yes, I agree the assumptions are key here. One key aspect of this >>>>>>>> paper is that it focuses on the steady-state behavior of bulk flows. >>>>>>>> >>>>>>>> Once you allow for short flows (like web pages, RPCs, etc) to >>>>>>>> dynamically enter and leave a bottleneck, the considerations become >>>>>>>> different. As is well-known, Reno/CUBIC will starve themselves if new >>>>>>>> flows >>>>>>>> enter and cause loss too frequently. For CUBIC, for a somewhat typical >>>>>>>> 30ms >>>>>>>> broadband path with a flow fair share of 25 Mbit/sec, if new flows >>>>>>>> enter >>>>>>>> and cause loss more frequently than roughly every 2 seconds then CUBIC >>>>>>>> will >>>>>>>> not be able to utilize its fair share. For a high-speed WAN path, with >>>>>>>> 100ms RTT and fair share of 10 Gbit/sec, if new flows enter and cause >>>>>>>> loss >>>>>>>> more frequently than roughly every 40 seconds then CUBIC will not be >>>>>>>> able >>>>>>>> to utilize its fair share. Basically, loss-based CC can starve itself >>>>>>>> in >>>>>>>> some very typical kinds of dynamic scenarios that happen in the real >>>>>>>> world. >>>>>>>> >>>>>>>> BBR is not trying to maintain a higher throughput than CUBIC in >>>>>>>> these kinds of scenarios with steady-state bulk flows. BBR is trying >>>>>>>> to be >>>>>>>> robust to the kinds of random packet loss that happen in the real world >>>>>>>> when there are flows dynamically entering/leaving a bottleneck. >>>>>>>> >>>>>>>> cheers, >>>>>>>> neal >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> On Thu, Aug 25, 2022 at 8:01 PM Dave Taht via Bloat < >>>>>>>> [email protected]> wrote: >>>>>>>> >>>>>>>>> I rather enjoyed this one. I can't help but wonder what would >>>>>>>>> happen >>>>>>>>> if we plugged some different assumptions into their model. >>>>>>>>> >>>>>>>>> https://www.comp.nus.edu.sg/~bleong/publications/imc2022-nash.pdf >>>>>>>>> >>>>>>>>> -- >>>>>>>>> FQ World Domination pending: >>>>>>>>> https://blog.cerowrt.org/post/state_of_fq_codel/ >>>>>>>>> Dave Täht CEO, TekLibre, LLC >>>>>>>>> _______________________________________________ >>>>>>>>> Bloat mailing list >>>>>>>>> [email protected] >>>>>>>>> https://lists.bufferbloat.net/listinfo/bloat >>>>>>>>> >>>>>>>> -- >>>>>>>> You received this message because you are subscribed to the Google >>>>>>>> Groups "BBR Development" group. >>>>>>>> To unsubscribe from this group and stop receiving emails from it, >>>>>>>> send an email to [email protected]. >>>>>>>> To view this discussion on the web visit >>>>>>>> https://groups.google.com/d/msgid/bbr-dev/CADVnQykKbnxpNcpuZATug_4VLhV1%3DaoTTQE2263o8HF9ye_TQg%40mail.gmail.com >>>>>>>> <https://groups.google.com/d/msgid/bbr-dev/CADVnQykKbnxpNcpuZATug_4VLhV1%3DaoTTQE2263o8HF9ye_TQg%40mail.gmail.com?utm_medium=email&utm_source=footer> >>>>>>>> . >>>>>>>> >>>>>>> >>>>>>> This electronic communication and the information and any files >>>>>>> transmitted with it, or attached to it, are confidential and are >>>>>>> intended >>>>>>> solely for the use of the individual or entity to whom it is addressed >>>>>>> and >>>>>>> may contain information that is confidential, legally privileged, >>>>>>> protected >>>>>>> by privacy laws, or otherwise restricted from disclosure to anyone >>>>>>> else. 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