[dpdk-users] scheduler issue

[Alex Kiselev]

On 2020-12-11 23:27, Alex Kiselev wrote:
> On 2020-12-11 23:06, Singh, Jasvinder wrote:
>>> On 11 Dec 2020, at 21:29, Alex Kiselev <alex at therouter.net> wrote:
>>> 
>>> On 2020-12-08 14:24, Singh, Jasvinder wrote:
>>>> <snip>
>>>>> > [JS] now, returning to 1 mbps pipes situation, try reducing tc period
>>>>> > first at subport and then at  pipe level, if that help in getting even
>>>>> > traffic across low bandwidth pipes.
>>>>> reducing subport tc from 10 to 5 period also solved the problem 
>>>>> with 1
>>>>> Mbit/s pipes.
>>>>> so, my second problem has been solved,
>>>>> but the first one with some of low bandwidth pipes stop 
>>>>> transmitting still
>>>>> remains.
>>>> I see, try removing "pkt_len <= pipe_tc_ov_credits" condition in the
>>>> grinder_credits_check() code for oversubscription case, instead use
>>>> this pkt_len <= pipe_tc_credits + pipe_tc_ov_credits;
>>> 
>>> if I do what you suggest, I will get this code
>>> 
>>>    enough_credits = (pkt_len <= subport_tb_credits) &&
>>>        (pkt_len <= subport_tc_credits) &&
>>>        (pkt_len <= pipe_tb_credits) &&
>>>        (pkt_len <= pipe_tc_credits) &&
>>>        (pkt_len <= pipe_tc_credits + pipe_tc_ov_credits);
>>> 
>>> And this doesn't make sense since if condition pkt_len <= 
>>> pipe_tc_credits is true
>>> then condition (pkt_len <= pipe_tc_credits + pipe_tc_ov_credits) is 
>>> also always true.
>> 
>> [JS] my suggestion is to remove“pkt_len <= pipe_tc_credits“, “ pkt_len
>> <= pipe_tc_ov_credits”and use only “pkt_len <= pipe_tc_credits +
>> pipe_tc_ov_credits“
>> While keeping tc_ov flag on.
>> 
>>> Your suggestion just turns off TC_OV feature.
> 
> I don't see your point.
> 
> This new suggestion will also effectively turn off the TC_OV feature 
> since
> the only effect of enabling TC_OV is adding additional condition
>   pkt_len <= pipe_tc_ov_credits
> which doesn't allow a pipe to spend more resources than it should.
> And in the case of support congestion a pipe should spent less than
> %100 of pipe's maximum rate.
> 
> And you suggest to allow pipe to spend 100% of it's rate plus some 
> extra.
> I guess effect of this would even more unfair support's bandwidth 
> distibution.
> 
> Btw, a pipe might stop transmitting even when there is no congestion
> at a subport.

While I am trying to find a cause of this
I want to make life of my client's sysadmins a little bit easier
by offering them a way to reset a subport or an entire port in order
to restore the connectivity when they detect a problematic pipe.

Any hints how to do that?
Thanks.

> 
> 
>>> 
>>> 
>>>>> >
>>>>> >
>>>>> >
>>>>> >>> rcv 0   rx rate 7324160 nb pkts 5722
>>>>> >>> rcv 1   rx rate 7281920 nb pkts 5689
>>>>> >>> rcv 2   rx rate 7226880 nb pkts 5646
>>>>> >>> rcv 3   rx rate 7124480 nb pkts 5566
>>>>> >>> rcv 4   rx rate 7324160 nb pkts 5722
>>>>> >>> rcv 5   rx rate 7271680 nb pkts 5681
>>>>> >>> rcv 6   rx rate 7188480 nb pkts 5616
>>>>> >>> rcv 7   rx rate 7150080 nb pkts 5586
>>>>> >>> rcv 8   rx rate 7328000 nb pkts 5725
>>>>> >>> rcv 9   rx rate 7249920 nb pkts 5664
>>>>> >>> rcv 10  rx rate 7188480 nb pkts 5616 rcv 11  rx rate 7179520 nb pkts
>>>>> >>> 5609 rcv 12  rx rate 7324160 nb pkts 5722 rcv 13  rx rate 7208960 nb
>>>>> >>> pkts 5632 rcv 14  rx rate 7152640 nb pkts 5588 rcv 15  rx rate
>>>>> >>> 7127040 nb pkts 5568 rcv 16  rx rate 7303680 nb pkts 5706 ....
>>>>> >>> rcv 587 rx rate 2406400 nb pkts 1880 rcv 588 rx rate 2406400 nb pkts
>>>>> >>> 1880 rcv 589 rx rate 2406400 nb pkts 1880 rcv 590 rx rate 2406400 nb
>>>>> >>> pkts 1880 rcv 591 rx rate 2406400 nb pkts 1880 rcv 592 rx rate
>>>>> >>> 2398720 nb pkts 1874 rcv 593 rx rate 2400000 nb pkts 1875 rcv 594 rx
>>>>> >>> rate 2400000 nb pkts 1875 rcv 595 rx rate 2400000 nb pkts 1875 rcv
>>>>> >>> 596 rx rate 2401280 nb pkts 1876 rcv 597 rx rate 2401280 nb pkts
>>>>> >>> 1876 rcv 598 rx rate 2401280 nb pkts 1876 rcv 599 rx rate 2402560 nb
>>>>> >>> pkts 1877 rx rate sum 3156416000
>>>>> >>
>>>>> >>
>>>>> >>
>>>>> >>>>> ... despite that there is _NO_ congestion...
>>>>> >>>>> congestion at the subport or pipe.
>>>>> >>>>>> And the subport !! doesn't use about 42 mbit/s of available
>>>>> >>>>>> bandwidth.
>>>>> >>>>>> The only difference is those test configurations is TC of
>>>>> >>>>>> generated traffic.
>>>>> >>>>>> Test 1 uses TC 1 while test 2 uses TC 3 (which is use TC_OV
>>>>> >>>>>> function).
>>>>> >>>>>> So, enabling TC_OV changes the results dramatically.
>>>>> >>>>>> ##
>>>>> >>>>>> ## test1
>>>>> >>>>>> ##
>>>>> >>>>>> hqos add profile  7 rate    2 M size 1000000 tc period 40
>>>>> >>>>>> # qos test port
>>>>> >>>>>> hqos add port 1 rate 10 G mtu 1522 frame overhead 24 queue sizes
>>>>> >>>>>> 64 64 64 64
>>>>> >>>>>> hqos add port 1 subport 0 rate 300 M size 1000000 tc period 10
>>>>> >>>>>> hqos add port 1 subport 0 pipes 2000 profile 7 hqos add port 1
>>>>> >>>>>> subport 0 pipes 200 profile 23 hqos set port 1 lcore 3 port 1
>>>>> >>>>>> subport rate 300 M number of tx flows 300 generator tx rate 1M TC
>>>>> >>>>>> 1 ...
>>>>> >>>>>> rcv 284 rx rate 995840  nb pkts 778 rcv 285 rx rate 995840  nb
>>>>> >>>>>> pkts 778 rcv 286 rx rate 995840  nb pkts 778 rcv 287 rx rate
>>>>> >>>>>> 995840  nb pkts 778 rcv 288 rx rate 995840  nb pkts 778 rcv 289
>>>>> >>>>>> rx rate 995840  nb pkts 778 rcv 290 rx rate 995840  nb pkts 778
>>>>> >>>>>> rcv 291 rx rate 995840  nb pkts 778 rcv 292 rx rate 995840  nb
>>>>> >>>>>> pkts 778 rcv 293 rx rate 995840  nb pkts 778 rcv 294 rx rate
>>>>> >>>>>> 995840  nb pkts 778 ...
>>>>> >>>>>> sum pipe's rx rate is 298 494 720 OK.
>>>>> >>>>>> The subport rate is equally distributed to 300 pipes.
>>>>> >>>>>> ##
>>>>> >>>>>> ##  test 2
>>>>> >>>>>> ##
>>>>> >>>>>> hqos add profile  7 rate    2 M size 1000000 tc period 40
>>>>> >>>>>> # qos test port
>>>>> >>>>>> hqos add port 1 rate 10 G mtu 1522 frame overhead 24 queue sizes
>>>>> >>>>>> 64 64 64 64
>>>>> >>>>>> hqos add port 1 subport 0 rate 300 M size 1000000 tc period 10
>>>>> >>>>>> hqos add port 1 subport 0 pipes 2000 profile 7 hqos add port 1
>>>>> >>>>>> subport 0 pipes 200 profile 23 hqos set port 1 lcore 3 port 1
>>>>> >>>>>> subport rate 300 M number of tx flows 300 generator tx rate 1M TC
>>>>> >>>>>> 3
>>>>> >>>>>> h5 ~ # rcli sh qos rcv
>>>>> >>>>>> rcv 0   rx rate 875520  nb pkts 684
>>>>> >>>>>> rcv 1   rx rate 856320  nb pkts 669
>>>>> >>>>>> rcv 2   rx rate 849920  nb pkts 664
>>>>> >>>>>> rcv 3   rx rate 853760  nb pkts 667
>>>>> >>>>>> rcv 4   rx rate 867840  nb pkts 678
>>>>> >>>>>> rcv 5   rx rate 844800  nb pkts 660
>>>>> >>>>>> rcv 6   rx rate 852480  nb pkts 666
>>>>> >>>>>> rcv 7   rx rate 855040  nb pkts 668
>>>>> >>>>>> rcv 8   rx rate 865280  nb pkts 676
>>>>> >>>>>> rcv 9   rx rate 846080  nb pkts 661
>>>>> >>>>>> rcv 10  rx rate 858880  nb pkts 671 rcv 11  rx rate 870400  nb
>>>>> >>>>>> pkts 680 rcv 12  rx rate 864000  nb pkts 675 rcv 13  rx rate
>>>>> >>>>>> 852480  nb pkts 666 rcv 14  rx rate 855040  nb pkts 668 rcv 15
>>>>> >>>>>> rx rate 857600  nb pkts 670 rcv 16  rx rate 864000  nb pkts 675
>>>>> >>>>>> rcv 17  rx rate 866560  nb pkts 677 rcv 18  rx rate 865280  nb
>>>>> >>>>>> pkts 676 rcv 19  rx rate 858880  nb pkts 671 rcv 20  rx rate
>>>>> >>>>>> 856320  nb pkts 669 rcv 21  rx rate 864000  nb pkts 675 rcv 22
>>>>> >>>>>> rx rate 869120  nb pkts 679 rcv 23  rx rate 856320  nb pkts 669
>>>>> >>>>>> rcv 24  rx rate 862720  nb pkts 674 rcv 25  rx rate 865280  nb
>>>>> >>>>>> pkts 676 rcv 26  rx rate 867840  nb pkts 678 rcv 27  rx rate
>>>>> >>>>>> 870400  nb pkts 680 rcv 28  rx rate 860160  nb pkts 672 rcv 29
>>>>> >>>>>> rx rate 870400  nb pkts 680 rcv 30  rx rate 869120  nb pkts 679
>>>>> >>>>>> rcv 31  rx rate 870400  nb pkts 680 rcv 32  rx rate 858880  nb
>>>>> >>>>>> pkts 671 rcv 33  rx rate 858880  nb pkts 671 rcv 34  rx rate
>>>>> >>>>>> 852480  nb pkts 666 rcv 35  rx rate 874240  nb pkts 683 rcv 36
>>>>> >>>>>> rx rate 855040  nb pkts 668 rcv 37  rx rate 853760  nb pkts 667
>>>>> >>>>>> rcv 38  rx rate 869120  nb pkts 679 rcv 39  rx rate 885760  nb
>>>>> >>>>>> pkts 692 rcv 40  rx rate 861440  nb pkts 673 rcv 41  rx rate
>>>>> >>>>>> 852480  nb pkts 666 rcv 42  rx rate 871680  nb pkts 681 ...
>>>>> >>>>>> ...
>>>>> >>>>>> rcv 288 rx rate 766720  nb pkts 599 rcv 289 rx rate 766720  nb
>>>>> >>>>>> pkts 599 rcv 290 rx rate 766720  nb pkts 599 rcv 291 rx rate
>>>>> >>>>>> 766720  nb pkts 599 rcv 292 rx rate 762880  nb pkts 596 rcv 293
>>>>> >>>>>> rx rate 762880  nb pkts 596 rcv 294 rx rate 762880  nb pkts 596
>>>>> >>>>>> rcv 295 rx rate 760320  nb pkts 594 rcv 296 rx rate 604160  nb
>>>>> >>>>>> pkts 472 rcv 297 rx rate 604160  nb pkts 472 rcv 298 rx rate
>>>>> >>>>>> 604160  nb pkts 472 rcv 299 rx rate 604160  nb pkts 472 rx rate
>>>>> >>>>>> sum 258839040 FAILED.
>>>>> >>>>>> The subport rate is distributed NOT equally between 300 pipes.
>>>>> >>>>>> Some subport bandwith (about 42) is not being used!