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From: Bob McMahon <bob.mcmahon@broadcom.com>
To: Taran Lynn <tflynn@ucdavis.edu>
Cc: Dave Taht <dave.taht@gmail.com>,
	ghosal@cs.ucdavis.edu, BBR Development <bbr-dev@googlegroups.com>,
	Make-Wifi-fast <make-wifi-fast@lists.bufferbloat.net>,
	ECN-Sane <ecn-sane@lists.bufferbloat.net>,
	bloat <bloat@lists.bufferbloat.net>,
	codel@lists.bufferbloat.net, flent-users <flent-users@flent.org>
Subject: [Flent-users] Re: [Make-wifi-fast] D* tcp looks pretty good, on paper
Date: Thu, 7 Jan 2021 12:25:57 -0800
Message-ID: <CAHb6LvrOLWDYjc8xrNMA-zazU1kdwiQne=afubiU2KtvVCVH4w@mail.gmail.com> (raw)
In-Reply-To: <CAO8Chnk7J8Y7GU8J1nXH+zX3MqukL7_1MJgF8Ce2T7e3DQ8Y1g@mail.gmail.com>


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FYI, one can try this out using iperf 2.1
<https://sourceforge.net/projects/iperf2/> with --trip-times
<https://iperf2.sourceforge.io/iperf-manpage.html>.  This gives end/end
delay at the application level. One can use --trip-times when clocks
are sync'd to get the write to read latencies which are the latencies at
the application level.

Note: I set up a Raspberry Pi 4 with a GPS hat from ubutronics for
solderless pulse per second
<https://www.satsignal.eu/ntp/Raspberry-Pi-NTP.html>.  Then configured it
as a PTP grandmaster.  This cost me around $200.

I also added support for a very crude --near-congestion option that paces
the writes based upon the weight of the RTT.  The tcp_info struct is
sampled and available
for other experiments though one would have to modify the source a bit.
This current technique used by iperf 2.1 is designed for test networks only
where all
traffic is under script control. We've had too many people measuring bloat
as latency. We really need separate measurements between the two phenomena,
bloat vs latency, because they require different eng actions for a
semiconductor supplier.

Below are examples over a 10G link, first with no write pacing then with
it. The server output, shown first, has the latency data (as well as the
net power
and little's law calculation.)  (Note: use --histograms for to get full
distributions.)

*No write pacing*

[rjmcmahon@localhost iperf2-code]$ src/iperf -s -i 1 -e
------------------------------------------------------------
Server listening on TCP port 5001 with pid 24568
Read buffer size:  128 KByte (Dist bin width=16.0 KByte)
TCP window size: 85.3 KByte (default)
------------------------------------------------------------
[  1] local 192.168.1.10%enp2s0 port 5001 connected with 192.168.1.62 port
50056 (MSS=1448) (trip-times) (sock=4) (peer 2.1.0-rc) on 2021-01-07
12:11:04 (PST)
[ ID] Interval        Transfer    Bandwidth    Burst Latency
avg/min/max/stdev (cnt/size) inP NetPwr  Reads=Dist
[  1] 0.00-1.00 sec  1.09 GBytes  9.34 Gbits/sec  2.959/1.180/3.681/0.388
ms (8905/131072) 3.31 MByte 394522
 18480=2459:2580:2475:2354:2203:2192:1974:2243
[  1] 1.00-2.00 sec  1.10 GBytes  9.41 Gbits/sec  2.993/2.302/3.703/0.359
ms (8978/131072) 3.36 MByte 393209
 19482=2526:2850:3102:2622:2344:2297:1867:1874
[  1] 2.00-3.00 sec  1.10 GBytes  9.42 Gbits/sec  3.010/2.302/3.692/0.347
ms (8978/131085) 3.38 MByte 391047
 19387=2563:2757:2928:2708:2432:2244:1829:1926
[  1] 3.00-4.00 sec  1.10 GBytes  9.41 Gbits/sec  3.009/2.301/3.668/0.348
ms (8979/131060) 3.38 MByte 391094
 18821=2456:2585:2660:2545:2270:2239:1906:2160
[  1] 4.00-5.00 sec  1.10 GBytes  9.42 Gbits/sec  2.985/2.299/3.696/0.359
ms (8979/131070) 3.35 MByte 394295
 19441=2509:2886:2959:2728:2336:2200:1971:1852
[  1] 5.00-6.00 sec  1.10 GBytes  9.41 Gbits/sec  2.977/2.258/3.671/0.363
ms (8978/131082) 3.34 MByte 395352
 18509=2352:2602:2464:2380:2263:2142:2095:2211
[  1] 6.00-7.00 sec  1.10 GBytes  9.41 Gbits/sec  2.980/2.290/3.680/0.363
ms (8978/131072) 3.34 MByte 394873
 18522=2407:2499:2565:2334:2213:2268:1999:2237
[  1] 7.00-8.00 sec  1.10 GBytes  9.42 Gbits/sec  2.980/2.253/3.702/0.362
ms (8979/131073) 3.35 MByte 394972
 18615=2427:2592:2493:2460:2281:2057:2062:2243
[  1] 8.00-9.00 sec  1.10 GBytes  9.41 Gbits/sec  2.976/2.277/3.663/0.364
ms (8979/131065) 3.34 MByte 395443
 18632=2338:2615:2647:2351:2192:2317:2063:2109
[  1] 9.00-10.00 sec  1.10 GBytes  9.41 Gbits/sec  2.976/2.293/3.690/0.366
ms (8978/131076) 3.34 MByte 395416
 18428=2281:2622:2497:2275:2178:2253:2129:2193
[  1] 0.00-10.00 sec  11.0 GBytes  9.41 Gbits/sec  2.984/1.180/3.703/0.362 ms
(89736/131072) 3.35 MByte 394014
 188367=24320:26609:26793:24757:22712:22211:19916:21049


[rjmcmahon@localhost iperf2-code]src/iperf -c 192.168.1.10 --trip-times -i
1 -e
------------------------------------------------------------
Client connecting to 192.168.1.10, TCP port 5001 with pid 18961 (1 flows)
Write buffer size: 131072 Byte
TCP window size: 85.0 KByte (default)
------------------------------------------------------------
[  1] local 192.168.1.62%enp2s0 port 50056 connected with 192.168.1.10 port
5001 (MSS=1448) (trip-times) (sock=3) (ct=0.41 ms) on 2021-01-07 12:11:04
(PST)
[ ID] Interval        Transfer    Bandwidth       Write/Err  Rtry
Cwnd/RTT        NetPwr
[  1] 0.00-1.00 sec  1.09 GBytes  9.37 Gbits/sec  8937/0          0
1508K/1099 us  1065750
[  1] 1.00-2.00 sec  1.10 GBytes  9.41 Gbits/sec  8975/0          0
1508K/1087 us  1082218
[  1] 2.00-3.00 sec  1.10 GBytes  9.41 Gbits/sec  8975/0          0
1508K/1081 us  1088225
[  1] 3.00-4.00 sec  1.10 GBytes  9.42 Gbits/sec  8984/0          0
1508K/1085 us  1085300
[  1] 4.00-5.00 sec  1.10 GBytes  9.42 Gbits/sec  8980/0          0
1508K/1105 us  1065182
[  1] 5.00-6.00 sec  1.10 GBytes  9.41 Gbits/sec  8975/0          0
1582K/1100 us  1069428
[  1] 6.00-7.00 sec  1.10 GBytes  9.42 Gbits/sec  8979/0          0
1582K/1121 us  1049862
[  1] 7.00-8.00 sec  1.10 GBytes  9.41 Gbits/sec  8976/0          0
1582K/1133 us  1038396
[  1] 8.00-9.00 sec  1.10 GBytes  9.41 Gbits/sec  8978/0          0
1582K/1115 us  1055394
[  1] 9.00-10.00 sec  1.10 GBytes  9.42 Gbits/sec  8986/0          0
1582K/1122 us  1049744
[  1] 0.00-10.00 sec  11.0 GBytes  9.41 Gbits/sec  89748/0          0
1582K/1122 us  1048294


*With write pacing*

[rjmcmahon@localhost iperf2-code]$ src/iperf -s -i 1 -e
------------------------------------------------------------
Server listening on TCP port 5001 with pid 24702
Read buffer size:  128 KByte (Dist bin width=16.0 KByte)
TCP window size: 85.3 KByte (default)
------------------------------------------------------------
[  1] local 192.168.1.10%enp2s0 port 5001 connected with 192.168.1.62 port
50072 (MSS=1448) (trip-times) (sock=4) (peer 2.1.0-rc) on 2021-01-07
12:14:59 (PST)
[ ID] Interval        Transfer    Bandwidth    Burst Latency
avg/min/max/stdev (cnt/size) inP NetPwr  Reads=Dist
[  1] 0.00-1.00 sec  1.08 GBytes  9.31 Gbits/sec  0.401/0.193/2.682/0.168
ms (8876/131084)  456 KByte 2904347
 19868=3296:2404:2508:2797:3559:1778:1551:1975
[  1] 1.00-2.00 sec  1.10 GBytes  9.41 Gbits/sec  0.400/0.219/0.627/0.053
ms (8971/131071)  460 KByte 2937822
 19117=3069:2267:2307:2510:3029:1824:1683:2428
[  1] 2.00-3.00 sec  1.09 GBytes  9.39 Gbits/sec  0.374/0.193/0.541/0.055
ms (8958/131060)  428 KByte 3143030
 18942=2846:2423:2304:2417:2927:1831:1856:2338
[  1] 3.00-4.00 sec  1.09 GBytes  9.39 Gbits/sec  0.385/0.190/0.664/0.070
ms (8952/131072)  441 KByte 3050401
 19248=3041:2175:2343:2749:3320:1805:1526:2289
[  1] 4.00-5.00 sec  1.09 GBytes  9.40 Gbits/sec  0.380/0.197/0.546/0.057
ms (8965/131075)  436 KByte 3095915
 19959=3321:2398:2551:2738:3500:1840:1532:2079
[  1] 5.00-6.00 sec  1.09 GBytes  9.39 Gbits/sec  0.369/0.198/0.536/0.051
ms (8956/131072)  423 KByte 3177431
 21060=3627:2456:2886:3189:4246:1813:1190:1653
[  1] 6.00-7.00 sec  1.09 GBytes  9.39 Gbits/sec  0.380/0.202/0.562/0.054
ms (8959/131077)  436 KByte 3086914
 19263=3044:2338:2424:2505:3155:1809:1636:2352
[  1] 7.00-8.00 sec  1.09 GBytes  9.40 Gbits/sec  0.376/0.198/0.541/0.053
ms (8965/131061)  432 KByte 3122495
 19137=3079:2303:2340:2455:3017:1822:1683:2438
[  1] 8.00-9.00 sec  1.10 GBytes  9.41 Gbits/sec  0.381/0.208/0.576/0.054
ms (8974/131073)  438 KByte 3083767
 19162=3050:2269:2392:2486:3019:1891:1667:2388
[  1] 9.00-10.00 sec  1.09 GBytes  9.40 Gbits/sec  0.371/0.194/0.582/0.057
ms (8964/131070)  425 KByte 3169244
 19143=3006:2411:2303:2462:3067:1744:1760:2390
[  1] 0.00-10.00 sec  10.9 GBytes  9.39 Gbits/sec  0.382/0.190/2.682/0.076
ms (89544/131072)  437 KByte 3074913
 194908=31380:23444:24362:26308:32839:18161:16084:22330


[rjmcmahon@localhost iperf2-code]$ src/iperf -c 192.168.1.10
--near-congestion=0.05
--trip-times -i 1 -e
------------------------------------------------------------
Client connecting to 192.168.1.10, TCP port 5001 with pid 19320 (1 flows)
Write buffer size: 131072 Byte
TCP near-congestion delay weight set to 0.0500
TCP window size: 85.0 KByte (default)
------------------------------------------------------------
[  1] local 192.168.1.62%enp2s0 port 50072 connected with 192.168.1.10 port
5001 (MSS=1448) (trip-times) (sock=3) (ct=0.40 ms) on 2021-01-07 12:14:59
(PST)
[ ID] Interval        Transfer    Bandwidth       Write/Err  Rtry
Cwnd/RTT        NetPwr
[  1] 0.00-1.00 sec  1.08 GBytes  9.31 Gbits/sec  8881/0          0
1135K/373 us  3120427
[  1] 1.00-2.00 sec  1.10 GBytes  9.41 Gbits/sec  8971/0          0
1135K/391 us  3007281
[  1] 2.00-3.00 sec  1.09 GBytes  9.39 Gbits/sec  8958/0          0
1135K/331 us  3547260
[  1] 3.00-4.00 sec  1.09 GBytes  9.39 Gbits/sec  8952/0          0
1135K/288 us  4074155
[  1] 4.00-5.00 sec  1.09 GBytes  9.40 Gbits/sec  8965/0          0
1135K/301 us  3903855
[  1] 5.00-6.00 sec  1.09 GBytes  9.39 Gbits/sec  8955/0          0
1135K/414 us  2835144
[  1] 6.00-7.00 sec  1.09 GBytes  9.40 Gbits/sec  8961/0          0
1135K/470 us  2499013
[  1] 7.00-8.00 sec  1.09 GBytes  9.40 Gbits/sec  8964/0          0
1135K/350 us  3356941
[  1] 8.00-9.00 sec  1.10 GBytes  9.41 Gbits/sec  8973/0          0
1135K/472 us  2491756
[  1] 9.00-10.00 sec  1.09 GBytes  9.40 Gbits/sec  8964/0          0
1135K/402 us  2922710
[  1] 0.00-10.00 sec  10.9 GBytes  9.39 Gbits/sec  89547/0          0
1135K/402 us  2919642

Bob


On Thu, Jan 7, 2021 at 11:22 AM Taran Lynn via Make-wifi-fast <
make-wifi-fast@lists.bufferbloat.net> wrote:

> The source can be found at https://github.com/lambda-11235/tcp_davis .
>
> The code mentioned in the paper can be found under the tag "arxiv_2020".
> The current master branch has an additional stable mode that I was testing
> out.
>
> On Thu, Jan 7, 2021 at 10:35 AM Dave Taht <dave.taht@gmail.com> wrote:
>
>> See: https://arxiv.org/pdf/2012.14996.pdf
>>
>> Things I really like:
>>
>> * they used flent
>> * Using "variance" as the principal signal. This is essentially one of
>> the great unpublished and unanalyzed improvements on the minstrel
>> algorithm as well
>> * Conventional ecn response
>> * outperforms bbr on variable links
>>
>> Only negative so far is I haven't found any published source to it. :(
>>
>> Otherwise a very promising start to a year.
>>
>> "The choice of feedback mechanism between delay and packet loss has
>> long been a point of contention in TCP congestion control. This has
>> partly been resolved, as it has become increasingly evident that delay
>> based methods are needed to facilitate modern interactive web
>> applications. However, what has not been resolved is what control
>> should be used, with the two candidates being the congestion window
>> and the pacing rate. BBR is a new delay based congestion control
>> algorithm that uses a pacing rate as its primary control and the
>> congestion window as a secondary control. We propose that a congestion
>> window first algorithm might give more desirable performance
>> characteristics in situations where latency must be minimized even at
>> the expense of some loss in throughput. To evaluate this hypothesis we
>> introduce a new congestion control algorithm called TCP D*, which is a
>> congestion window first algorithm that adopts BBR's approach of
>> maximizing delivery rate while minimizing latency. In this paper, we
>> discuss the key features of this algorithm, discuss the differences
>> and similarity to BBR, and present some preliminary results based on a
>> real implementation."
>>
>>
>>
>>
>> --
>> "For a successful technology, reality must take precedence over public
>> relations, for Mother Nature cannot be fooled" - Richard Feynman
>>
>> dave@taht.net <Dave Täht> CTO, TekLibre, LLC Tel: 1-831-435-0729
>>
> _______________________________________________
> Make-wifi-fast mailing list
> Make-wifi-fast@lists.bufferbloat.net
> https://lists.bufferbloat.net/listinfo/make-wifi-fast

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  reply	other threads:[~2021-01-07 20:26 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-07 18:35 [Flent-users] " Dave Taht
2021-01-07 19:20 ` [Flent-users] " Taran Lynn
2021-01-07 20:25   ` Bob McMahon [this message]
2021-01-07 21:41     ` [Flent-users] Re: [Make-wifi-fast] " Dave Taht
2021-01-07 22:22       ` Bob McMahon
2021-01-08 14:35       ` [Flent-users] Re: [Ecn-sane] " Rodney W. Grimes
2021-01-08 17:52         ` Bob McMahon
2021-01-08 15:38 ` [Flent-users] Re: [bbr-dev] " Neal Cardwell
2021-01-08 16:13   ` [Flent-users] Re: [Make-wifi-fast] " Jonathan Morton
2021-01-08 16:24     ` Bryson Richard

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