X-Git-Url: https://gerrit.fd.io/r/gitweb?a=blobdiff_plain;f=doc%2Fguides%2Fcryptodevs%2Fscheduler.rst;fp=doc%2Fguides%2Fcryptodevs%2Fscheduler.rst;h=32e56537380d742f4e6bdb1086e58951add62bef;hb=7595afa4d30097c1177b69257118d8ad89a539be;hp=0000000000000000000000000000000000000000;hpb=ce3d555e43e3795b5d9507fcfc76b7a0a92fd0d6;p=deb_dpdk.git diff --git a/doc/guides/cryptodevs/scheduler.rst b/doc/guides/cryptodevs/scheduler.rst new file mode 100644 index 00000000..32e56537 --- /dev/null +++ b/doc/guides/cryptodevs/scheduler.rst @@ -0,0 +1,172 @@ +.. BSD LICENSE + Copyright(c) 2017 Intel Corporation. All rights reserved. + All rights reserved. + + Redistribution and use in source and binary forms, with or without + modification, are permitted provided that the following conditions + are met: + + * Redistributions of source code must retain the above copyright + notice, this list of conditions and the following disclaimer. + * Redistributions in binary form must reproduce the above copyright + notice, this list of conditions and the following disclaimer in + the documentation and/or other materials provided with the + distribution. + * Neither the name of Intel Corporation nor the names of its + contributors may be used to endorse or promote products derived + from this software without specific prior written permission. + + THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +Cryptodev Scheduler Poll Mode Driver Library +============================================ + +Scheduler PMD is a software crypto PMD, which has the capabilities of +attaching hardware and/or software cryptodevs, and distributes ingress +crypto ops among them in a certain manner. + +.. figure:: img/scheduler-overview.* + + Cryptodev Scheduler Overview + + +The Cryptodev Scheduler PMD library (**librte_pmd_crypto_scheduler**) acts as +a software crypto PMD and shares the same API provided by librte_cryptodev. +The PMD supports attaching multiple crypto PMDs, software or hardware, as +slaves, and distributes the crypto workload to them with certain behavior. +The behaviors are categorizes as different "modes". Basically, a scheduling +mode defines certain actions for scheduling crypto ops to its slaves. + +The librte_pmd_crypto_scheduler library exports a C API which provides an API +for attaching/detaching slaves, set/get scheduling modes, and enable/disable +crypto ops reordering. + +Limitations +----------- + +* Sessionless crypto operation is not supported +* OOP crypto operation is not supported when the crypto op reordering feature + is enabled. + + +Installation +------------ + +To build DPDK with CRYTPO_SCHEDULER_PMD the user is required to set +CONFIG_RTE_LIBRTE_PMD_CRYPTO_SCHEDULER=y in config/common_base, and +recompile DPDK + + +Initialization +-------------- + +To use the PMD in an application, user must: + +* Call rte_vdev_init("crpyto_scheduler") within the application. + +* Use --vdev="crpyto_scheduler" in the EAL options, which will call + rte_vdev_init() internally. + + +The following parameters (all optional) can be provided in the previous +two calls: + +* socket_id: Specify the socket where the memory for the device is going + to be allocated (by default, socket_id will be the socket where the core + that is creating the PMD is running on). + +* max_nb_sessions: Specify the maximum number of sessions that can be + created. This value may be overwritten internally if there are too + many devices are attached. + +* slave: If a cryptodev has been initialized with specific name, it can be + attached to the scheduler using this parameter, simply filling the name + here. Multiple cryptodevs can be attached initially by presenting this + parameter multiple times. + +* mode: Specify the scheduling mode of the PMD. The supported scheduling + mode parameter values are specified in the "Cryptodev Scheduler Modes + Overview" section. + +* ordering: Specify the status of the crypto operations ordering feature. + The value of this parameter can be "enable" or "disable". This feature + is disabled by default. + +Example: + +.. code-block:: console + + ... --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" ... + +.. note:: + + * The scheduler cryptodev cannot be started unless the scheduling mode + is set and at least one slave is attached. Also, to configure the + scheduler in the run-time, like attach/detach slave(s), change + scheduling mode, or enable/disable crypto op ordering, one should stop + the scheduler first, otherwise an error will be returned. + + * The crypto op reordering feature requires using the userdata field of + every mbuf to be processed to store temporary data. By the end of + processing, the field is set to pointing to NULL, any previously + stored value of this field will be lost. + + +Cryptodev Scheduler Modes Overview +---------------------------------- + +Currently the Crypto Scheduler PMD library supports following modes of +operation: + +* **CDEV_SCHED_MODE_ROUNDROBIN:** + + *Initialization mode parameter*: **round-robin** + + Round-robin mode, which distributes the enqueued burst of crypto ops + among its slaves in a round-robin manner. This mode may help to fill + the throughput gap between the physical core and the existing cryptodevs + to increase the overall performance. + +* **CDEV_SCHED_MODE_PKT_SIZE_DISTR:** + + *Initialization mode parameter*: **packet-size-distr** + + Packet-size based distribution mode, which works with 2 slaves, the primary + slave and the secondary slave, and distributes the enqueued crypto + operations to them based on their data lengths. A crypto operation will be + distributed to the primary slave if its data length is equal to or bigger + than the designated threshold, otherwise it will be handled by the secondary + slave. + + A typical usecase in this mode is with the QAT cryptodev as the primary and + a software cryptodev as the secondary slave. This may help applications to + process additional crypto workload than what the QAT cryptodev can handle on + its own, by making use of the available CPU cycles to deal with smaller + crypto workloads. + + The threshold is set to 128 bytes by default. It can be updated by calling + function **rte_cryptodev_scheduler_option_set**. The parameter of + **option_type** must be **CDEV_SCHED_OPTION_THRESHOLD** and **option** should + point to a rte_cryptodev_scheduler_threshold_option structure filled with + appropriate threshold value. Please NOTE this threshold has be a power-of-2 + unsigned integer. + +* **CDEV_SCHED_MODE_FAILOVER:** + + *Initialization mode parameter*: **fail-over** + + Fail-over mode, which works with 2 slaves, the primary slave and the + secondary slave. In this mode, the scheduler will enqueue the incoming + crypto operation burst to the primary slave. When one or more crypto + operations fail to be enqueued, then they will be enqueued to the secondary + slave.