From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from dpdk.org (dpdk.org [92.243.14.124]) by inbox.dpdk.org (Postfix) with ESMTP id AF6DBA09EE for ; Sat, 12 Dec 2020 01:54:12 +0100 (CET) Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id 0B279BC84; Sat, 12 Dec 2020 01:54:11 +0100 (CET) Received: from wh10.alp1.flow.ch (wh10.alp1.flow.ch [185.119.84.194]) by dpdk.org (Postfix) with ESMTP id EF8DBAC9E for ; Sat, 12 Dec 2020 01:54:08 +0100 (CET) Received: from [::1] (port=59252 helo=wh10.alp1.flow.ch) by wh10.alp1.flow.ch with esmtpa (Exim 4.92) (envelope-from ) id 1kntAl-00HZuw-Gs; Sat, 12 Dec 2020 01:54:07 +0100 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Date: Sat, 12 Dec 2020 01:54:07 +0100 From: Alex Kiselev To: "Singh, Jasvinder" Cc: users@dpdk.org, "Dumitrescu, Cristian" , "Dharmappa, Savinay" In-Reply-To: <4ed02c4280efcfe2bf9e6c51803f807b@therouter.net> References: <7909ed9ded69f36b262ff151244c8b0d@therouter.net> , <85944DCD-F0D5-4F64-9E8C-68D1428491B8@intel.com> <4ed02c4280efcfe2bf9e6c51803f807b@therouter.net> Message-ID: X-Sender: alex@therouter.net User-Agent: Roundcube Webmail/1.3.8 X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - wh10.alp1.flow.ch X-AntiAbuse: Original Domain - dpdk.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - therouter.net X-Get-Message-Sender-Via: wh10.alp1.flow.ch: authenticated_id: alex@therouter.net X-Authenticated-Sender: wh10.alp1.flow.ch: alex@therouter.net X-Source: X-Source-Args: X-Source-Dir: Subject: Re: [dpdk-users] scheduler issue X-BeenThere: users@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK usage discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: users-bounces@dpdk.org Sender: "users" On 2020-12-12 01:45, Alex Kiselev wrote: > On 2020-12-12 01:20, Singh, Jasvinder wrote: >>> On 11 Dec 2020, at 23:37, Alex Kiselev wrote: >> >>> On 2020-12-11 23:55, Singh, Jasvinder wrote: >>> On 11 Dec 2020, at 22:27, Alex Kiselev wrote: >> >>>> On 2020-12-11 23:06, Singh, Jasvinder wrote: >> >>> On 11 Dec 2020, at 21:29, Alex Kiselev wrote: >> >>> On 2020-12-08 14:24, Singh, Jasvinder wrote: >> >>> >> >>>> [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. >> >>> Although I didn’t try this solution but the idea here is - in a >> >>> particular round, of pkt_len is less than pipe_tc_credits( which is >>> a >> >>> constant value each time) but greater than pipe_tc_ov_credits, then >>> it >> >>> might hit the situation when no packet will be scheduled from the >>> pipe >> >>> even though there are fixed credits greater than packet size is >> >>> available. >> >> But that is a perfectly normal situation and that's exactly the idea >> behind TC_OV. >> It means a pipe should wait for the next subport->tc_ov_period_id >> when pipe_tc_ov_credits will be reset to a new value >> >> But here it’s not guaranteed that new value of pipe_tc_ov_credits >> will be sufficient for low bandwidth pipe to send their packets as >> each time pipe_tc_ov_credits is freshly computed. >> >>> pipe->tc_ov_credits = subport->tc_ov_wm * params->tc_ov_weight; >>> >>> which allows the pipe to continue transmitting. >> >> No that won’t happen if new tc_ov_credits value is again less than >> pkt_len and will hit deadlock. > > new tc_ov_credits can't not be less than subport->tc_ov_wm_min, > and tc_ov_wm_min is equal to port->mtu. > all my scheduler ports configured with mtu 1522. etherdev ports also > uses > the same mtu, therefore there should be no packets bigger that 1522. also, tc_ov_credits is set to tc_ov_wm_min only in the case of constant congestion and today I detected the problem when there was no congestion. so, it's highly unlikely that tc_ov_credits is always set to a value less than pkt_size. The only scenario in which this might be the case is when scheduler port get a corrupted mbuf with incorrect pkt len which cause a queue deadlock. > > Maybe I should increase port's MTU? to 1540? > >> >>> And it could not cause a permanent pipe stop which is what I am >>> facing. >> >>>> In fairness, pipe should send the as much as packets which >>> >>>> consumes pipe_tc_credits, regardless of extra pipe_tc_ov_credits >>>> which >>> >>>> is extra on top of pipe_tc_credits. >>> >>> I think it's quite the opposite. That's why after I reduced the >>> support tc_period >>> I got much more fairness. Since reducing subport tc_period also >>> reduce the tc_ov_wm_max value. >>> s->tc_ov_wm_max = rte_sched_time_ms_to_bytes(params->tc_period, >>> port->pipe_tc3_rate_max) >>> as a result a pipe transmits less bytes in one round. so pipe >>> rotation inside a grinder >>> happens much more often and a pipe can't monopolise resources. >>> >>> in other sos implementation this is called "quantum". >> >> Yes, so reducing tc period makes the case when all pipes ( high n low >> bandwidth) gets lower values of tc_ov_credits values which allow >> lesser transmission from higher bw pipes and leave bandwidth for low >> bw pipes. So, here is the thing- Either tune tc period to a value >> which prevent high bw pipe hogging most of bw or makes changes in the >> code, where oversubscription add extra credits on top of guaranteed. >> >> One question, don’t your low bw pipes have higher priority traffic >> tc0, tc1, tc2 . Packets from those tc must be going out. Isn’t this >> the case ? > > well, it would be the case after I find out > what's going on. Right now I am using a tos2tc map configured > in such a way that all ipv4 packets with any TOS values > goes into TC3. > >> >>>> >> >>>> >> >>>> >> >>>>>> 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!