xref: /dpdk/doc/guides/cryptodevs/scheduler.rst (revision 35b09d76f89e7d5a4f38a2926cf6915028ed1e56)
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31Cryptodev Scheduler Poll Mode Driver Library
32============================================
33
34Scheduler PMD is a software crypto PMD, which has the capabilities of
35attaching hardware and/or software cryptodevs, and distributes ingress
36crypto ops among them in a certain manner.
37
38.. figure:: img/scheduler-overview.*
39
40   Cryptodev Scheduler Overview
41
42
43The Cryptodev Scheduler PMD library (**librte_pmd_crypto_scheduler**) acts as
44a software crypto PMD and shares the same API provided by librte_cryptodev.
45The PMD supports attaching multiple crypto PMDs, software or hardware, as
46slaves, and distributes the crypto workload to them with certain behavior.
47The behaviors are categorizes as different "modes". Basically, a scheduling
48mode defines certain actions for scheduling crypto ops to its slaves.
49
50The librte_pmd_crypto_scheduler library exports a C API which provides an API
51for attaching/detaching slaves, set/get scheduling modes, and enable/disable
52crypto ops reordering.
53
54Limitations
55-----------
56
57* Sessionless crypto operation is not supported
58* OOP crypto operation is not supported when the crypto op reordering feature
59  is enabled.
60
61
62Installation
63------------
64
65To build DPDK with CRYTPO_SCHEDULER_PMD the user is required to set
66CONFIG_RTE_LIBRTE_PMD_CRYPTO_SCHEDULER=y in config/common_base, and
67recompile DPDK
68
69
70Initialization
71--------------
72
73To use the PMD in an application, user must:
74
75* Call rte_eal_vdev_init("crpyto_scheduler") within the application.
76
77* Use --vdev="crpyto_scheduler" in the EAL options, which will call
78  rte_eal_vdev_init() internally.
79
80
81The following parameters (all optional) can be provided in the previous
82two calls:
83
84* socket_id: Specify the socket where the memory for the device is going
85  to be allocated (by default, socket_id will be the socket where the core
86  that is creating the PMD is running on).
87
88* max_nb_sessions: Specify the maximum number of sessions that can be
89  created. This value may be overwritten internally if there are too
90  many devices are attached.
91
92* slave: If a cryptodev has been initialized with specific name, it can be
93  attached to the scheduler using this parameter, simply filling the name
94  here. Multiple cryptodevs can be attached initially by presenting this
95  parameter multiple times.
96
97Example:
98
99.. code-block:: console
100
101    ... --vdev "crypto_aesni_mb_pmd,name=aesni_mb_1" --vdev "crypto_aesni_mb_pmd,name=aesni_mb_2" --vdev "crypto_scheduler_pmd,slave=aesni_mb_1,slave=aesni_mb_2" ...
102
103.. note::
104
105    * The scheduler cryptodev cannot be started unless the scheduling mode
106      is set and at least one slave is attached. Also, to configure the
107      scheduler in the run-time, like attach/detach slave(s), change
108      scheduling mode, or enable/disable crypto op ordering, one should stop
109      the scheduler first, otherwise an error will be returned.
110
111    * The crypto op reordering feature requires using the userdata field of
112      every mbuf to be processed to store temporary data. By the end of
113      processing, the field is set to pointing to NULL, any previously
114      stored value of this field will be lost.
115
116
117Cryptodev Scheduler Modes Overview
118----------------------------------
119
120Currently the Crypto Scheduler PMD library supports following modes of
121operation:
122
123*   **CDEV_SCHED_MODE_ROUNDROBIN:**
124
125   Round-robin mode, which distributes the enqueued burst of crypto ops
126   among its slaves in a round-robin manner. This mode may help to fill
127   the throughput gap between the physical core and the existing cryptodevs
128   to increase the overall performance.
129