[Cake] [PATCH] q_cake: Update xstats format to use per-tin structure

[Sebastian Moeller]

Hi Jonathan,



> On Mar 6, 2018, at 12:46, Jonathan Morton <chromatix99 at gmail.com> wrote:
> 
>> On 6 Mar, 2018, at 1:17 pm, Toke Høiland-Jørgensen <toke at toke.dk> wrote:
>> 
>>> So far it looks like everything is working fine and behaving as it
>>> should (on a plain Ethernet interface).  The one wrinkle is that it
>>> takes a few thousand packets for the avg_off value to converge on the
>>> true value, but that should easily be tolerable in most cases.
>> 
>> So, erm, what do the new stats mean? ;)
> 
> avg_off: the average observed offset of the transport header in packets.  This should converge to 14 on Ethernet.
> 
> max/min_tran: tracking the transport-layer size of packets; max_tran = max_len-avg_off if GSO is off.
> 
> max/min_adj: tracking the overhead-adjusted size of packets; these should be the adjusted sizes of the corresponding transport-layer sizes, so can be used to check the calculations.
> 
> It's probably feasible to lay these out better in the output, so they take up fewer lines on screen.

Great this matches what I deduced from the numbers. I note that by replacing a cake instance with itself (so not changing the configuration) will reset the counters.
Question: am I right to assume that the _adj values are what you pass in as the true packet size into cake's calculation?
I really like these outputs so far (running flent I saw:

qdisc cake 8003: dev eth0 root refcnt 6 unlimited diffserv3 triple-isolate rtt 100.0ms noatm overhead 34 mpu 64 
 Sent 269164303 bytes 611190 pkt (dropped 0, overlimits 0 requeues 2) 
 backlog 0b 0p requeues 2 
 memory used: 10880b of 15140Kb
 capacity estimate: 0bit
                 Bulk   Best Effort      Voice
  thresh          0bit        0bit        0bit
  target         5.0ms       5.0ms       5.0ms
  interval     100.0ms     100.0ms     100.0ms
  pk_delay        14us        11us         8us
  av_delay         2us         2us         1us
  sp_delay         0us         0us         0us
  pkts           61400      395326      154464
  bytes       17617151   183250552    68296600
  way_inds           0           0           0
  way_miss           3          89          11
  way_cols           0           0           0
  drops              0           0           0
  marks              0           0           0
  ack_drop           0           0           0
  sp_flows           2          13           7
  bk_flows           0           0           0
  un_flows           0           0           0
  max_len         3012        3028        3012
  max_tran        1492
  max_adj         1526
  min_tran          28
  min_adj           64
  avg_off           14


Which is pretty much what I expected (speedtest ran over an effective MTU1492 PPPoE link*), but I still want to make more in-depth tests. Now we just need to carry this nto lede to get more testers. Plus it might make sense to merge tc-adv with iproute2-cake-next so that we have one master repository for the tc changes as well. I believe that before the xstats and Jonathan's recent updates iproute2-cake-next  was more up to date, but I am probably wrong...

Best Regards
	Sebastian

*) Interestingly takling stats later revealed:
qdisc cake 8003: dev eth0 root refcnt 6 unlimited diffserv3 triple-isolate rtt 100.0ms noatm overhead 34 mpu 64 
 Sent 743833445 bytes 1965042 pkt (dropped 0, overlimits 0 requeues 6) 
 backlog 0b 0p requeues 6 
 memory used: 16346b of 15140Kb
 capacity estimate: 0bit
                 Bulk   Best Effort      Voice
  thresh          0bit        0bit        0bit
  target         5.0ms       5.0ms       5.0ms
  interval     100.0ms     100.0ms     100.0ms
  pk_delay         8us        12us         9us
  av_delay         1us         3us         3us
  sp_delay         1us         1us         1us
  pkts          167869     1382188      414985
  bytes       49022886   511662935   183147624
  way_inds           0         341           0
  way_miss           6        1137          20
  way_cols           0           0           0
  drops              0           0           0
  marks              0           0           0
  ack_drop           0           0           0
  sp_flows           1           1           0
  bk_flows           0           0           1
  un_flows           0           0           0
  max_len         3012        3028        3012
  max_tran        1500
  max_adj         1534
  min_tran          28
  min_adj           64
  avg_off           14

Son between this sample and the speedtest the host exchanged MTU1500 packets with the local network...

> 
> - Jonathan Morton
>