1.. SPDX-License-Identifier: BSD-3-Clause 2 Copyright(c) 2017 Intel Corporation. 3 4Cryptodev Scheduler Poll Mode Driver Library 5============================================ 6 7Scheduler PMD is a software crypto PMD, which has the capabilities of 8attaching hardware and/or software cryptodevs, and distributes ingress 9crypto ops among them in a certain manner. 10 11.. figure:: img/scheduler-overview.* 12 13 Cryptodev Scheduler Overview 14 15 16The Cryptodev Scheduler PMD library (**librte_pmd_crypto_scheduler**) acts as 17a software crypto PMD and shares the same API provided by librte_cryptodev. 18The PMD supports attaching multiple crypto PMDs, software or hardware, as 19slaves, and distributes the crypto workload to them with certain behavior. 20The behaviors are categorizes as different "modes". Basically, a scheduling 21mode defines certain actions for scheduling crypto ops to its slaves. 22 23The librte_pmd_crypto_scheduler library exports a C API which provides an API 24for attaching/detaching slaves, set/get scheduling modes, and enable/disable 25crypto ops reordering. 26 27Limitations 28----------- 29 30* Sessionless crypto operation is not supported 31* OOP crypto operation is not supported when the crypto op reordering feature 32 is enabled. 33 34 35Installation 36------------ 37 38To build DPDK with CRYTPO_SCHEDULER_PMD the user is required to set 39CONFIG_RTE_LIBRTE_PMD_CRYPTO_SCHEDULER=y in config/common_base, and 40recompile DPDK 41 42 43Initialization 44-------------- 45 46To use the PMD in an application, user must: 47 48* Call rte_vdev_init("crypto_scheduler") within the application. 49 50* Use --vdev="crypto_scheduler" in the EAL options, which will call 51 rte_vdev_init() internally. 52 53 54The following parameters (all optional) can be provided in the previous 55two calls: 56 57* socket_id: Specify the socket where the memory for the device is going 58 to be allocated (by default, socket_id will be the socket where the core 59 that is creating the PMD is running on). 60 61* max_nb_sessions: Specify the maximum number of sessions that can be 62 created. This value may be overwritten internally if there are too 63 many devices are attached. 64 65* slave: If a cryptodev has been initialized with specific name, it can be 66 attached to the scheduler using this parameter, simply filling the name 67 here. Multiple cryptodevs can be attached initially by presenting this 68 parameter multiple times. 69 70* mode: Specify the scheduling mode of the PMD. The supported scheduling 71 mode parameter values are specified in the "Cryptodev Scheduler Modes 72 Overview" section. 73 74* mode_param: Specify the mode-specific parameter. Some scheduling modes 75 may be initialized with specific parameters other than the default ones, 76 such as the **threshold** packet size of **packet-size-distr** mode. This 77 parameter fulfills the purpose. 78 79* ordering: Specify the status of the crypto operations ordering feature. 80 The value of this parameter can be "enable" or "disable". This feature 81 is disabled by default. 82 83Example: 84 85.. code-block:: console 86 87 ... --vdev "crypto_aesni_mb0,name=aesni_mb_1" --vdev "crypto_aesni_mb1,name=aesni_mb_2" --vdev "crypto_scheduler,slave=aesni_mb_1,slave=aesni_mb_2" ... 88 89.. note:: 90 91 * The scheduler cryptodev cannot be started unless the scheduling mode 92 is set and at least one slave is attached. Also, to configure the 93 scheduler in the run-time, like attach/detach slave(s), change 94 scheduling mode, or enable/disable crypto op ordering, one should stop 95 the scheduler first, otherwise an error will be returned. 96 97 * The crypto op reordering feature requires using the userdata field of 98 every mbuf to be processed to store temporary data. By the end of 99 processing, the field is set to pointing to NULL, any previously 100 stored value of this field will be lost. 101 102 103Cryptodev Scheduler Modes Overview 104---------------------------------- 105 106Currently the Crypto Scheduler PMD library supports following modes of 107operation: 108 109* **CDEV_SCHED_MODE_ROUNDROBIN:** 110 111 *Initialization mode parameter*: **round-robin** 112 113 Round-robin mode, which distributes the enqueued burst of crypto ops 114 among its slaves in a round-robin manner. This mode may help to fill 115 the throughput gap between the physical core and the existing cryptodevs 116 to increase the overall performance. 117 118* **CDEV_SCHED_MODE_PKT_SIZE_DISTR:** 119 120 *Initialization mode parameter*: **packet-size-distr** 121 122 Packet-size based distribution mode, which works with 2 slaves, the primary 123 slave and the secondary slave, and distributes the enqueued crypto 124 operations to them based on their data lengths. A crypto operation will be 125 distributed to the primary slave if its data length is equal to or bigger 126 than the designated threshold, otherwise it will be handled by the secondary 127 slave. 128 129 A typical usecase in this mode is with the QAT cryptodev as the primary and 130 a software cryptodev as the secondary slave. This may help applications to 131 process additional crypto workload than what the QAT cryptodev can handle on 132 its own, by making use of the available CPU cycles to deal with smaller 133 crypto workloads. 134 135 The threshold is set to 128 bytes by default. It can be updated by calling 136 function **rte_cryptodev_scheduler_option_set**. The parameter of 137 **option_type** must be **CDEV_SCHED_OPTION_THRESHOLD** and **option** should 138 point to a rte_cryptodev_scheduler_threshold_option structure filled with 139 appropriate threshold value. Please NOTE this threshold has be a power-of-2 140 unsigned integer. It is possible to use **mode_param** initialization 141 parameter to achieve the same purpose. For example: 142 143 ... --vdev "crypto_scheduler,mode=packet-size-distr,mode_param=threshold:512" ... 144 145 The above parameter will overwrite the threshold value to 512. 146 147* **CDEV_SCHED_MODE_FAILOVER:** 148 149 *Initialization mode parameter*: **fail-over** 150 151 Fail-over mode, which works with 2 slaves, the primary slave and the 152 secondary slave. In this mode, the scheduler will enqueue the incoming 153 crypto operation burst to the primary slave. When one or more crypto 154 operations fail to be enqueued, then they will be enqueued to the secondary 155 slave. 156 157* **CDEV_SCHED_MODE_MULTICORE:** 158 159 *Initialization mode parameter*: **multi-core** 160 161 Multi-core mode, which distributes the workload with several (up to eight) 162 worker cores. The enqueued bursts are distributed among the worker cores in a 163 round-robin manner. If scheduler cannot enqueue entire burst to the same worker, 164 it will enqueue the remaining operations to the next available worker. 165 For pure small packet size (64 bytes) traffic however the multi-core mode is not 166 an optimal solution, as it doesn't give significant per-core performance improvement. 167 For mixed traffic (IMIX) the optimal number of worker cores is around 2-3. 168 For large packets (1.5 Kbytes) scheduler shows linear scaling in performance 169 up to eight cores. 170 Each worker uses its own slave cryptodev. Only software cryptodevs 171 are supported. Only the same type of cryptodevs should be used concurrently. 172 173 The multi-core mode uses one extra parameter: 174 175 * corelist: Semicolon-separated list of logical cores to be used as workers. 176 The number of worker cores should be equal to the number of slave cryptodevs. 177 These cores should be present in EAL core list parameter and 178 should not be used by the application or any other process. 179 180 Example: 181 ... --vdev "crypto_aesni_mb1,name=aesni_mb_1" --vdev "crypto_aesni_mb_pmd2,name=aesni_mb_2" \ 182 --vdev "crypto_scheduler,slave=aesni_mb_1,slave=aesni_mb_2,mode=multi-core,corelist=23;24" ... 183