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diff --git a/vpp/vnet/vnet/devices/dpdk/qos_doc.md b/vpp/vnet/vnet/devices/dpdk/qos_doc.md new file mode 100644 index 00000000..9bd0659d --- /dev/null +++ b/vpp/vnet/vnet/devices/dpdk/qos_doc.md @@ -0,0 +1,404 @@ +# QoS Hierarchical Scheduler {#qos_doc} + +The Quality-of-Service (QoS) scheduler performs egress-traffic management by +prioritizing the transmission of the packets of different type services and +subcribers based on the Service Level Agreements (SLAs). The QoS scheduler can +be enabled on one or more NIC output interfaces depending upon the +requirement. + + +## Overview + +The QoS schdeuler supports a number of scheduling and shaping levels which +construct hierarchical-tree. The first level in the hierarchy is port (i.e. +the physical interface) that constitutes the root node of the tree. The +subsequent level is subport which represents the group of the +users/subscribers. The individual user/subscriber is represented by the pipe +at the next level. Each user can have different traffic type based on the +criteria of specific loss rate, jitter, and latency. These traffic types are +represented at the traffic-class level in the form of different traffic- +classes. The last level contains number of queues which are grouped together +to host the packets of the specific class type traffic. + +The QoS scheduler implementation requires flow classification, enqueue and +dequeue operations. The flow classification is mandatory stage for HQoS where +incoming packets are classified by mapping the packet fields information to +5-tuple (HQoS subport, pipe, traffic class, queue within traffic class, and +color) and storing that information in mbuf sched field. The enqueue operation +uses this information to determine the queue for storing the packet, and at +this stage, if the specific queue is full, QoS drops the packet. The dequeue +operation consists of scheduling the packet based on its length and available +credits, and handing over the scheduled packet to the output interface. + +For more information on QoS Scheduler, please refer DPDK Programmer's Guide- +http://dpdk.org/doc/guides/prog_guide/qos_framework.html + + +### QoS Schdeuler Parameters + +Following illustrates the default HQoS configuration for each 10GbE output +port: + +Single subport (subport 0): + - Subport rate set to 100% of port rate + - Each of the 4 traffic classes has rate set to 100% of port rate + +4K pipes per subport 0 (pipes 0 .. 4095) with identical configuration: + - Pipe rate set to 1/4K of port rate + - Each of the 4 traffic classes has rate set to 100% of pipe rate + - Within each traffic class, the byte-level WRR weights for the 4 queues are set to 1:1:1:1 + + +#### Port configuration + +``` +port { + rate 1250000000 /* Assuming 10GbE port */ + frame_overhead 24 /* Overhead fields per Ethernet frame: + * 7B (Preamble) + + * 1B (Start of Frame Delimiter (SFD)) + + * 4B (Frame Check Sequence (FCS)) + + * 12B (Inter Frame Gap (IFG)) + */ + mtu 1522 /* Assuming Ethernet/IPv4 pkt (FCS not included) */ + n_subports_per_port 1 /* Number of subports per output interface */ + n_pipes_per_subport 4096 /* Number of pipes (users/subscribers) */ + queue_sizes 64 64 64 64 /* Packet queue size for each traffic class. + * All queues within the same pipe traffic class + * have the same size. Queues from different + * pipes serving the same traffic class have + * the same size. */ +} +``` + + +#### Subport configuration + +``` +subport 0 { + tb_rate 1250000000 /* Subport level token bucket rate (bytes per second) */ + tb_size 1000000 /* Subport level token bucket size (bytes) */ + tc0_rate 1250000000 /* Subport level token bucket rate for traffic class 0 (bytes per second) */ + tc1_rate 1250000000 /* Subport level token bucket rate for traffic class 1 (bytes per second) */ + tc2_rate 1250000000 /* Subport level token bucket rate for traffic class 2 (bytes per second) */ + tc3_rate 1250000000 /* Subport level token bucket rate for traffic class 3 (bytes per second) */ + tc_period 10 /* Time interval for refilling the token bucket associated with traffic class (Milliseconds) */ + pipe 0 4095 profile 0 /* pipes (users/subscribers) configured with pipe profile 0 */ +} +``` + + +#### Pipe configuration + +``` +pipe_profile 0 { + tb_rate 305175 /* Pipe level token bucket rate (bytes per second) */ + tb_size 1000000 /* Pipe level token bucket size (bytes) */ + tc0_rate 305175 /* Pipe level token bucket rate for traffic class 0 (bytes per second) */ + tc1_rate 305175 /* Pipe level token bucket rate for traffic class 1 (bytes per second) */ + tc2_rate 305175 /* Pipe level token bucket rate for traffic class 2 (bytes per second) */ + tc3_rate 305175 /* Pipe level token bucket rate for traffic class 3 (bytes per second) */ + tc_period 40 /* Time interval for refilling the token bucket associated with traffic class at pipe level (Milliseconds) */ + tc3_oversubscription_weight 1 /* Weight traffic class 3 oversubscription */ + tc0_wrr_weights 1 1 1 1 /* Pipe queues WRR weights for traffic class 0 */ + tc1_wrr_weights 1 1 1 1 /* Pipe queues WRR weights for traffic class 1 */ + tc2_wrr_weights 1 1 1 1 /* Pipe queues WRR weights for traffic class 2 */ + tc3_wrr_weights 1 1 1 1 /* Pipe queues WRR weights for traffic class 3 */ +} +``` + + +#### Random Early Detection (RED) parameters per traffic class and color (Green / Yellow / Red) + +``` +red { + tc0_wred_min 48 40 32 /* Minimum threshold for traffic class 0 queue (min_th) in number of packets */ + tc0_wred_max 64 64 64 /* Maximum threshold for traffic class 0 queue (max_th) in number of packets */ + tc0_wred_inv_prob 10 10 10 /* Inverse of packet marking probability for traffic class 0 queue (maxp = 1 / maxp_inv) */ + tc0_wred_weight 9 9 9 /* Traffic Class 0 queue weight */ + tc1_wred_min 48 40 32 /* Minimum threshold for traffic class 1 queue (min_th) in number of packets */ + tc1_wred_max 64 64 64 /* Maximum threshold for traffic class 1 queue (max_th) in number of packets */ + tc1_wred_inv_prob 10 10 10 /* Inverse of packet marking probability for traffic class 1 queue (maxp = 1 / maxp_inv) */ + tc1_wred_weight 9 9 9 /* Traffic Class 1 queue weight */ + tc2_wred_min 48 40 32 /* Minimum threshold for traffic class 2 queue (min_th) in number of packets */ + tc2_wred_max 64 64 64 /* Maximum threshold for traffic class 2 queue (max_th) in number of packets */ + tc2_wred_inv_prob 10 10 10 /* Inverse of packet marking probability for traffic class 2 queue (maxp = 1 / maxp_inv) */ + tc2_wred_weight 9 9 9 /* Traffic Class 2 queue weight */ + tc3_wred_min 48 40 32 /* Minimum threshold for traffic class 3 queue (min_th) in number of packets */ + tc3_wred_max 64 64 64 /* Maximum threshold for traffic class 3 queue (max_th) in number of packets */ + tc3_wred_inv_prob 10 10 10 /* Inverse of packet marking probability for traffic class 3 queue (maxp = 1 / maxp_inv) */ + tc3_wred_weight 9 9 9 /* Traffic Class 3 queue weight */ +} +``` + + +### DPDK QoS Scheduler Integration in VPP + +The Hierarchical Quaity-of-Service (HQoS) scheduler object could be seen as +part of the logical NIC output interface. To enable HQoS on specific output +interface, vpp startup.conf file has to be configured accordingly. The output +interface that requires HQoS, should have "hqos" parameter specified in dpdk +section. Another optional parameter "hqos-thread" has been defined which can +be used to associate the output interface with specific hqos thread. In cpu +section of the config file, "corelist-hqos-threads" is introduced to assign +logical cpu cores to run the HQoS threads. A HQoS thread can run multiple HQoS +objects each associated with different output interfaces. All worker threads +instead of writing packets to NIC TX queue directly, write the packets to a +software queues. The hqos_threads read the software queues, and enqueue the +packets to HQoS objects, as well as dequeue packets from HQOS objects and +write them to NIC output interfaces. The worker threads need to be able to +send the packets to any output interface, therefore, each HQoS object +associated with NIC output interface should have software queues equal to +worker threads count. + +Following illustrates the sample startup configuration file with 4x worker +threads feeding 2x hqos threads that handle each QoS scheduler for 1x output +interface. + +``` +dpdk { + socket-mem 16384,16384 + + dev 0000:02:00.0 { + num-rx-queues 2 + hqos + } + dev 0000:06:00.0 { + num-rx-queues 2 + hqos + } + + num-mbufs 1000000 +} + +cpu { + main-core 0 + corelist-workers 1, 2, 3, 4 + corelist-hqos-threads 5, 6 +} +``` + + +### QoS scheduler CLI Commands + +Each QoS scheduler instance is initialised with default parameters required to +configure hqos port, subport, pipe and queues. Some of the parameters can be +re-configured in run-time through CLI commands. + + +#### Configuration + +Following commands can be used to configure QoS scheduler parameters. + +The command below can be used to set the subport level parameters such as +token bucket rate (bytes per seconds), token bucket size (bytes), traffic +class rates (bytes per seconds) and token update period (Milliseconds). + +``` +set dpdk interface hqos subport <if-name> subport <n> [rate <n>] + [bktsize <n>] [tc0 <n>] [tc1 <n>] [tc2 <n>] [tc3 <n>] [period <n>] +``` + +For setting the pipe profile, following command can be used. + +``` +set dpdk interface hqos pipe <if-name> subport <n> pipe <n> profile <n> +``` + +To assign QoS scheduler instance to the specific thread, following command can +be used. + +``` +set dpdk interface hqos placement <if-name> thread <n> +``` + +The command below is used to set the packet fields required for classifiying +the incoming packet. As a result of classification process, packet field +information will be mapped to 5 tuples (subport, pipe, traffic class, pipe, +color) and stored in packet mbuf. + +``` +set dpdk interface hqos pktfield <if-name> id <n> offset <n> mask <n> +``` + +The DSCP table entries used for idenfiying the traffic class and queue can be set using the command below; + +``` +set dpdk interface hqos tctbl <if-name> entry <n> tc <n> queue <n> +``` + + +#### Show Command + +The QoS Scheduler configuration can displayed using the command below. + +``` + vpp# show dpdk interface hqos TenGigabitEthernet2/0/0 + Thread: + Input SWQ size = 4096 packets + Enqueue burst size = 256 packets + Dequeue burst size = 220 packets + Packet field 0: slab position = 0, slab bitmask = 0x0000000000000000 + Packet field 1: slab position = 40, slab bitmask = 0x0000000fff000000 + Packet field 2: slab position = 8, slab bitmask = 0x00000000000000fc + Packet field 2 translation table: + [ 0 .. 15]: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 + [16 .. 31]: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 + [32 .. 47]: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 + [48 .. 63]: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 + Port: + Rate = 1250000000 bytes/second + MTU = 1514 bytes + Frame overhead = 24 bytes + Number of subports = 1 + Number of pipes per subport = 4096 + Packet queue size: TC0 = 64, TC1 = 64, TC2 = 64, TC3 = 64 packets + Number of pipe profiles = 1 + Pipe profile 0: + Rate = 305175 bytes/second + Token bucket size = 1000000 bytes + Traffic class rate: TC0 = 305175, TC1 = 305175, TC2 = 305175, TC3 = 305175 bytes/second + TC period = 40 milliseconds + TC0 WRR weights: Q0 = 1, Q1 = 1, Q2 = 1, Q3 = 1 + TC1 WRR weights: Q0 = 1, Q1 = 1, Q2 = 1, Q3 = 1 + TC2 WRR weights: Q0 = 1, Q1 = 1, Q2 = 1, Q3 = 1 + TC3 WRR weights: Q0 = 1, Q1 = 1, Q2 = 1, Q3 = 1 +``` + +The QoS Scheduler placement over the logical cpu cores can be displayed using +below command. + +``` + vpp# show dpdk interface hqos placement + Thread 5 (vpp_hqos-threads_0 at lcore 5): + TenGigabitEthernet2/0/0 queue 0 + Thread 6 (vpp_hqos-threads_1 at lcore 6): + TenGigabitEthernet4/0/1 queue 0 +``` + + +### QoS Scheduler Binary APIs + +This section explans the available binary APIs for configuring QoS scheduler +parameters in run-time. + +The following API can be used to set the pipe profile of a pipe that belongs +to a given subport: + +``` +sw_interface_set_dpdk_hqos_pipe rx <intfc> | sw_if_index <id> + subport <subport-id> pipe <pipe-id> profile <profile-id> +``` + +The data structures used for set the pipe profile parameter are as follows; + +``` + /** \\brief DPDK interface HQoS pipe profile set request + @param client_index - opaque cookie to identify the sender + @param context - sender context, to match reply w/ request + @param sw_if_index - the interface + @param subport - subport ID + @param pipe - pipe ID within its subport + @param profile - pipe profile ID + */ + define sw_interface_set_dpdk_hqos_pipe { + u32 client_index; + u32 context; + u32 sw_if_index; + u32 subport; + u32 pipe; + u32 profile; + }; + + /** \\brief DPDK interface HQoS pipe profile set reply + @param context - sender context, to match reply w/ request + @param retval - request return code + */ + define sw_interface_set_dpdk_hqos_pipe_reply { + u32 context; + i32 retval; + }; +``` + +The following API can be used to set the subport level parameters, for +example- token bucket rate (bytes per seconds), token bucket size (bytes), +traffic class rate (bytes per seconds) and tokens update period. + +``` +sw_interface_set_dpdk_hqos_subport rx <intfc> | sw_if_index <id> + subport <subport-id> [rate <n>] [bktsize <n>] + [tc0 <n>] [tc1 <n>] [tc2 <n>] [tc3 <n>] [period <n>] +``` + +The data structures used for set the subport level parameter are as follows; + +``` + /** \\brief DPDK interface HQoS subport parameters set request + @param client_index - opaque cookie to identify the sender + @param context - sender context, to match reply w/ request + @param sw_if_index - the interface + @param subport - subport ID + @param tb_rate - subport token bucket rate (measured in bytes/second) + @param tb_size - subport token bucket size (measured in credits) + @param tc_rate - subport traffic class 0 .. 3 rates (measured in bytes/second) + @param tc_period - enforcement period for rates (measured in milliseconds) + */ + define sw_interface_set_dpdk_hqos_subport { + u32 client_index; + u32 context; + u32 sw_if_index; + u32 subport; + u32 tb_rate; + u32 tb_size; + u32 tc_rate[4]; + u32 tc_period; + }; + + /** \\brief DPDK interface HQoS subport parameters set reply + @param context - sender context, to match reply w/ request + @param retval - request return code + */ + define sw_interface_set_dpdk_hqos_subport_reply { + u32 context; + i32 retval; + }; +``` + +The following API can be used set the DSCP table entry. The DSCP table have +64 entries to map the packet DSCP field onto traffic class and hqos input +queue. + +``` +sw_interface_set_dpdk_hqos_tctbl rx <intfc> | sw_if_index <id> + entry <n> tc <n> queue <n> +``` + +The data structures used for setting DSCP table entries are given below. + +``` + /** \\brief DPDK interface HQoS tctbl entry set request + @param client_index - opaque cookie to identify the sender + @param context - sender context, to match reply w/ request + @param sw_if_index - the interface + @param entry - entry index ID + @param tc - traffic class (0 .. 3) + @param queue - traffic class queue (0 .. 3) + */ + define sw_interface_set_dpdk_hqos_tctbl { + u32 client_index; + u32 context; + u32 sw_if_index; + u32 entry; + u32 tc; + u32 queue; + }; + + /** \\brief DPDK interface HQoS tctbl entry set reply + @param context - sender context, to match reply w/ request + @param retval - request return code + */ + define sw_interface_set_dpdk_hqos_tctbl_reply { + u32 context; + i32 retval; + }; +``` |