1 .. SPDX-License-Identifier: BSD-3-Clause
2 Copyright(c) 2010-2014 Intel Corporation.
4 QoS Scheduler Sample Application
5 ================================
7 The QoS sample application demonstrates the use of the DPDK to provide QoS scheduling.
12 The architecture of the QoS scheduler application is shown in the following figure.
14 .. _figure_qos_sched_app_arch:
16 .. figure:: img/qos_sched_app_arch.*
18 QoS Scheduler Application Architecture
21 There are two flavors of the runtime execution for this application,
22 with two or three threads per each packet flow configuration being used.
23 The RX thread reads packets from the RX port,
24 classifies the packets based on the double VLAN (outer and inner) and
25 the lower byte of the IP destination address and puts them into the ring queue.
26 The worker thread dequeues the packets from the ring and calls the QoS scheduler enqueue/dequeue functions.
27 If a separate TX core is used, these are sent to the TX ring.
28 Otherwise, they are sent directly to the TX port.
29 The TX thread, if present, reads from the TX ring and write the packets to the TX port.
31 Compiling the Application
32 -------------------------
34 To compile the sample application see :doc:`compiling`.
36 The application is located in the ``qos_sched`` sub-directory.
40 This application is intended as a linux only.
44 To get statistics on the sample app using the command line interface as described in the next section,
45 DPDK must be compiled defining *RTE_SCHED_COLLECT_STATS*, which can be done by changing the relevant
46 entry in the ``config/rte_config.h`` file.
50 Number of grinders is currently set to 8.
51 This can be modified by specifying RTE_SCHED_PORT_N_GRINDERS=N
52 in CFLAGS, where N is number of grinders.
54 Running the Application
55 -----------------------
59 In order to run the application, a total of at least 4
60 G of huge pages must be set up for each of the used sockets (depending on the cores in use).
62 The application has a number of command line options:
64 .. code-block:: console
66 ./<build_dir>/examples/dpdk-qos_sched [EAL options] -- <APP PARAMS>
68 Mandatory application parameters include:
70 * --pfc "RX PORT, TX PORT, RX LCORE, WT LCORE, TX CORE": Packet flow configuration.
71 Multiple pfc entities can be configured in the command line,
72 having 4 or 5 items (if TX core defined or not).
74 Optional application parameters include:
76 * -i: It makes the application to start in the interactive mode.
77 In this mode, the application shows a command line that can be used for obtaining statistics while
78 scheduling is taking place (see interactive mode below for more information).
80 * --mnc n: Main core index (the default value is 1).
82 * --rsz "A, B, C": Ring sizes:
84 * A = Size (in number of buffer descriptors) of each of the NIC RX rings read
85 by the I/O RX lcores (the default value is 128).
87 * B = Size (in number of elements) of each of the software rings used
88 by the I/O RX lcores to send packets to worker lcores (the default value is 8192).
90 * C = Size (in number of buffer descriptors) of each of the NIC TX rings written
91 by worker lcores (the default value is 256)
93 * --bsz "A, B, C, D": Burst sizes
95 * A = I/O RX lcore read burst size from the NIC RX (the default value is 64)
97 * B = I/O RX lcore write burst size to the output software rings,
98 worker lcore read burst size from input software rings,QoS enqueue size (the default value is 64)
100 * C = QoS dequeue size (the default value is 32)
102 * D = Worker lcore write burst size to the NIC TX (the default value is 64)
104 * --msz M: Mempool size (in number of mbufs) for each pfc (default 2097152)
106 * --rth "A, B, C": The RX queue threshold parameters
108 * A = RX prefetch threshold (the default value is 8)
110 * B = RX host threshold (the default value is 8)
112 * C = RX write-back threshold (the default value is 4)
114 * --tth "A, B, C": TX queue threshold parameters
116 * A = TX prefetch threshold (the default value is 36)
118 * B = TX host threshold (the default value is 0)
120 * C = TX write-back threshold (the default value is 0)
122 * --cfg FILE: Profile configuration to load
124 Refer to *DPDK Getting Started Guide* for general information on running applications and
125 the Environment Abstraction Layer (EAL) options.
127 The profile configuration file defines all the port/subport/pipe/traffic class/queue parameters
128 needed for the QoS scheduler configuration.
130 The profile file has the following format:
132 .. literalinclude:: ../../../examples/qos_sched/profile.cfg
133 :start-after: Data Plane Development Kit (DPDK) Programmer's Guide
138 These are the commands that are currently working under the command line interface:
142 * --quit: Quits the application.
146 * stats app: Shows a table with in-app calculated statistics.
148 * stats port X subport Y: For a specific subport, it shows the number of packets that
149 went through the scheduler properly and the number of packets that were dropped.
150 The same information is shown in bytes.
151 The information is displayed in a table separating it in different traffic classes.
153 * stats port X subport Y pipe Z: For a specific pipe, it shows the number of packets that
154 went through the scheduler properly and the number of packets that were dropped.
155 The same information is shown in bytes.
156 This information is displayed in a table separating it in individual queues.
160 All of these commands work the same way, averaging the number of packets throughout a specific subset of queues.
162 Two parameters can be configured for this prior to calling any of these commands:
164 * qavg n X: n is the number of times that the calculation will take place.
165 Bigger numbers provide higher accuracy. The default value is 10.
167 * qavg period X: period is the number of microseconds that will be allowed between each calculation.
168 The default value is 100.
170 The commands that can be used for measuring average queue size are:
172 * qavg port X subport Y: Show average queue size per subport.
174 * qavg port X subport Y tc Z: Show average queue size per subport for a specific traffic class.
176 * qavg port X subport Y pipe Z: Show average queue size per pipe.
178 * qavg port X subport Y pipe Z tc A: Show average queue size per pipe for a specific traffic class.
180 * qavg port X subport Y pipe Z tc A q B: Show average queue size of a specific queue.
185 The following is an example command with a single packet flow configuration:
187 .. code-block:: console
189 ./<build_dir>/examples/dpdk-qos_sched -l 1,5,7 -n 4 -- --pfc "3,2,5,7" --cfg ./profile.cfg
191 This example uses a single packet flow configuration which creates one RX thread on lcore 5 reading
192 from port 3 and a worker thread on lcore 7 writing to port 2.
194 Another example with 2 packet flow configurations using different ports but sharing the same core for QoS scheduler is given below:
196 .. code-block:: console
198 ./<build_dir>/examples/dpdk-qos_sched -l 1,2,6,7 -n 4 -- --pfc "3,2,2,6,7" --pfc "1,0,2,6,7" --cfg ./profile.cfg
200 Note that independent cores for the packet flow configurations for each of the RX, WT and TX thread are also supported,
201 providing flexibility to balance the work.
203 The EAL coremask/corelist is constrained to contain the default main core 1 and the RX, WT and TX cores only.
208 The Port/Subport/Pipe/Traffic Class/Queue are the hierarchical entities in a typical QoS application:
210 * A subport represents a predefined group of users.
212 * A pipe represents an individual user/subscriber.
214 * A traffic class is the representation of a different traffic type with a specific loss rate,
215 delay and jitter requirements; such as data voice, video or data transfers.
217 * A queue hosts packets from one or multiple connections of the same type belonging to the same user.
219 The traffic flows that need to be configured are application dependent.
220 This application classifies based on the QinQ double VLAN tags and the IP destination address as indicated in the following table.
222 .. _table_qos_scheduler_1:
224 .. table:: Entity Types
226 +----------------+-------------------------+--------------------------------------------------+----------------------------------+
227 | **Level Name** | **Siblings per Parent** | **QoS Functional Description** | **Selected By** |
229 +================+=========================+==================================================+==================================+
230 | Port | - | Ethernet port | Physical port |
232 +----------------+-------------------------+--------------------------------------------------+----------------------------------+
233 | Subport | Config (8) | Traffic shaped (token bucket) | Outer VLAN tag |
235 +----------------+-------------------------+--------------------------------------------------+----------------------------------+
236 | Pipe | Config (4k) | Traffic shaped (token bucket) | Inner VLAN tag |
238 +----------------+-------------------------+--------------------------------------------------+----------------------------------+
239 | Traffic Class | 13 | TCs of the same pipe services in strict priority | Destination IP address (0.0.0.X) |
241 +----------------+-------------------------+--------------------------------------------------+----------------------------------+
242 | Queue | High Priority TC: 1, | Queue of lowest priority traffic | Destination IP address (0.0.0.X) |
243 | | Lowest Priority TC: 4 | class (Best effort) serviced in WRR | |
244 +----------------+-------------------------+--------------------------------------------------+----------------------------------+
246 Please refer to the "QoS Scheduler" chapter in the *DPDK Programmer's Guide* for more information about these parameters.