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 Number of grinders is currently set to 8.
45 This can be modified by specifying RTE_SCHED_PORT_N_GRINDERS=N
46 in CFLAGS, where N is number of grinders.
48 Running the Application
49 -----------------------
53 In order to run the application, a total of at least 4
54 G of huge pages must be set up for each of the used sockets (depending on the cores in use).
56 The application has a number of command line options:
58 .. code-block:: console
60 ./<build_dir>/examples/dpdk-qos_sched [EAL options] -- <APP PARAMS>
62 Mandatory application parameters include:
64 * --pfc "RX PORT, TX PORT, RX LCORE, WT LCORE, TX CORE": Packet flow configuration.
65 Multiple pfc entities can be configured in the command line,
66 having 4 or 5 items (if TX core defined or not).
68 Optional application parameters include:
70 * -i: It makes the application to start in the interactive mode.
71 In this mode, the application shows a command line that can be used for obtaining statistics while
72 scheduling is taking place (see interactive mode below for more information).
74 * --mnc n: Main core index (the default value is 1).
76 * --rsz "A, B, C": Ring sizes:
78 * A = Size (in number of buffer descriptors) of each of the NIC RX rings read
79 by the I/O RX lcores (the default value is 128).
81 * B = Size (in number of elements) of each of the software rings used
82 by the I/O RX lcores to send packets to worker lcores (the default value is 8192).
84 * C = Size (in number of buffer descriptors) of each of the NIC TX rings written
85 by worker lcores (the default value is 256)
87 * --bsz "A, B, C, D": Burst sizes
89 * A = I/O RX lcore read burst size from the NIC RX (the default value is 64)
91 * B = I/O RX lcore write burst size to the output software rings,
92 worker lcore read burst size from input software rings,QoS enqueue size (the default value is 64)
94 * C = QoS dequeue size (the default value is 32)
96 * D = Worker lcore write burst size to the NIC TX (the default value is 64)
98 * --msz M: Mempool size (in number of mbufs) for each pfc (default 2097152)
100 * --rth "A, B, C": The RX queue threshold parameters
102 * A = RX prefetch threshold (the default value is 8)
104 * B = RX host threshold (the default value is 8)
106 * C = RX write-back threshold (the default value is 4)
108 * --tth "A, B, C": TX queue threshold parameters
110 * A = TX prefetch threshold (the default value is 36)
112 * B = TX host threshold (the default value is 0)
114 * C = TX write-back threshold (the default value is 0)
116 * --cfg FILE: Profile configuration to load
118 Refer to *DPDK Getting Started Guide* for general information on running applications and
119 the Environment Abstraction Layer (EAL) options.
121 The profile configuration file defines all the port/subport/pipe/traffic class/queue parameters
122 needed for the QoS scheduler configuration.
124 The profile file has the following format:
126 .. literalinclude:: ../../../examples/qos_sched/profile.cfg
127 :start-after: Data Plane Development Kit (DPDK) Programmer's Guide
132 These are the commands that are currently working under the command line interface:
136 * --quit: Quits the application.
140 * stats app: Shows a table with in-app calculated statistics.
142 * stats port X subport Y: For a specific subport, it shows the number of packets that
143 went through the scheduler properly and the number of packets that were dropped.
144 The same information is shown in bytes.
145 The information is displayed in a table separating it in different traffic classes.
147 * stats port X subport Y pipe Z: For a specific pipe, it shows the number of packets that
148 went through the scheduler properly and the number of packets that were dropped.
149 The same information is shown in bytes.
150 This information is displayed in a table separating it in individual queues.
154 All of these commands work the same way, averaging the number of packets throughout a specific subset of queues.
156 Two parameters can be configured for this prior to calling any of these commands:
158 * qavg n X: n is the number of times that the calculation will take place.
159 Bigger numbers provide higher accuracy. The default value is 10.
161 * qavg period X: period is the number of microseconds that will be allowed between each calculation.
162 The default value is 100.
164 The commands that can be used for measuring average queue size are:
166 * qavg port X subport Y: Show average queue size per subport.
168 * qavg port X subport Y tc Z: Show average queue size per subport for a specific traffic class.
170 * qavg port X subport Y pipe Z: Show average queue size per pipe.
172 * qavg port X subport Y pipe Z tc A: Show average queue size per pipe for a specific traffic class.
174 * qavg port X subport Y pipe Z tc A q B: Show average queue size of a specific queue.
179 The following is an example command with a single packet flow configuration:
181 .. code-block:: console
183 ./<build_dir>/examples/dpdk-qos_sched -l 1,5,7 -n 4 -- --pfc "3,2,5,7" --cfg ./profile.cfg
185 This example uses a single packet flow configuration which creates one RX thread on lcore 5 reading
186 from port 3 and a worker thread on lcore 7 writing to port 2.
188 Another example with 2 packet flow configurations using different ports but sharing the same core for QoS scheduler is given below:
190 .. code-block:: console
192 ./<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
194 Note that independent cores for the packet flow configurations for each of the RX, WT and TX thread are also supported,
195 providing flexibility to balance the work.
197 The EAL coremask/corelist is constrained to contain the default main core 1 and the RX, WT and TX cores only.
202 The Port/Subport/Pipe/Traffic Class/Queue are the hierarchical entities in a typical QoS application:
204 * A subport represents a predefined group of users.
206 * A pipe represents an individual user/subscriber.
208 * A traffic class is the representation of a different traffic type with a specific loss rate,
209 delay and jitter requirements; such as data voice, video or data transfers.
211 * A queue hosts packets from one or multiple connections of the same type belonging to the same user.
213 The traffic flows that need to be configured are application dependent.
214 This application classifies based on the QinQ double VLAN tags and the IP destination address as indicated in the following table.
216 .. _table_qos_scheduler_1:
218 .. table:: Entity Types
220 +----------------+-------------------------+--------------------------------------------------+----------------------------------+
221 | **Level Name** | **Siblings per Parent** | **QoS Functional Description** | **Selected By** |
223 +================+=========================+==================================================+==================================+
224 | Port | - | Ethernet port | Physical port |
226 +----------------+-------------------------+--------------------------------------------------+----------------------------------+
227 | Subport | Config (8) | Traffic shaped (token bucket) | Outer VLAN tag |
229 +----------------+-------------------------+--------------------------------------------------+----------------------------------+
230 | Pipe | Config (4k) | Traffic shaped (token bucket) | Inner VLAN tag |
232 +----------------+-------------------------+--------------------------------------------------+----------------------------------+
233 | Traffic Class | 13 | TCs of the same pipe services in strict priority | Destination IP address (0.0.0.X) |
235 +----------------+-------------------------+--------------------------------------------------+----------------------------------+
236 | Queue | High Priority TC: 1, | Queue of lowest priority traffic | Destination IP address (0.0.0.X) |
237 | | Lowest Priority TC: 4 | class (Best effort) serviced in WRR | |
238 +----------------+-------------------------+--------------------------------------------------+----------------------------------+
240 Please refer to the "QoS Scheduler" chapter in the *DPDK Programmer's Guide* for more information about these parameters.