X-Git-Url: http://git.droids-corp.org/?a=blobdiff_plain;f=doc%2Fguides%2Frawdevs%2Fioat.rst;h=250cfc48a60431a71a2268ac2e819a6f0a8069b7;hb=205708169132d6f3496a3dd64955d6d7db418aef;hp=b898f98d5f0153262658b4ec6c8b87b225ec469a;hpb=d09d396fadcb8c97bdbbc1868917394f485fdb09;p=dpdk.git diff --git a/doc/guides/rawdevs/ioat.rst b/doc/guides/rawdevs/ioat.rst index b898f98d5f..250cfc48a6 100644 --- a/doc/guides/rawdevs/ioat.rst +++ b/doc/guides/rawdevs/ioat.rst @@ -37,9 +37,64 @@ No additional compilation steps are necessary. Device Setup ------------- +Depending on support provided by the PMD, HW devices can either use the kernel configured driver +or be bound to a user-space IO driver for use. +For example, Intel\ |reg| DSA devices can use the IDXD kernel driver or DPDK-supported drivers, +such as ``vfio-pci``. + +Intel\ |reg| DSA devices using idxd kernel driver +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +To use a Intel\ |reg| DSA device bound to the IDXD kernel driver, the device must first be configured. +The `accel-config `_ utility library can be used for configuration. + +.. note:: + The device configuration can also be done by directly interacting with the sysfs nodes. + An example of how this may be done can be seen in the script ``dpdk_idxd_cfg.py`` + included in the driver source directory. + +There are some mandatory configuration steps before being able to use a device with an application. +The internal engines, which do the copies or other operations, +and the work-queues, which are used by applications to assign work to the device, +need to be assigned to groups, and the various other configuration options, +such as priority or queue depth, need to be set for each queue. + +To assign an engine to a group:: + + $ accel-config config-engine dsa0/engine0.0 --group-id=0 + $ accel-config config-engine dsa0/engine0.1 --group-id=1 + +To assign work queues to groups for passing descriptors to the engines a similar accel-config command can be used. +However, the work queues also need to be configured depending on the use-case. +Some configuration options include: + +* mode (Dedicated/Shared): Indicates whether a WQ may accept jobs from multiple queues simultaneously. +* priority: WQ priority between 1 and 15. Larger value means higher priority. +* wq-size: the size of the WQ. Sum of all WQ sizes must be less that the total-size defined by the device. +* type: WQ type (kernel/mdev/user). Determines how the device is presented. +* name: identifier given to the WQ. + +Example configuration for a work queue:: + + $ accel-config config-wq dsa0/wq0.0 --group-id=0 \ + --mode=dedicated --priority=10 --wq-size=8 \ + --type=user --name=app1 + +Once the devices have been configured, they need to be enabled:: + + $ accel-config enable-device dsa0 + $ accel-config enable-wq dsa0/wq0.0 + +Check the device configuration:: + + $ accel-config list + +Devices using VFIO/UIO drivers +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + The HW devices to be used will need to be bound to a user-space IO driver for use. The ``dpdk-devbind.py`` script can be used to view the state of the devices -and to bind them to a suitable DPDK-supported kernel driver, such as ``vfio-pci``. +and to bind them to a suitable DPDK-supported driver, such as ``vfio-pci``. For example:: $ dpdk-devbind.py -b vfio-pci 00:04.0 00:04.1 @@ -47,9 +102,16 @@ For example:: Device Probing and Initialization ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -Once bound to a suitable kernel device driver, the HW devices will be found -as part of the PCI scan done at application initialization time. No vdev -parameters need to be passed to create or initialize the device. +For devices bound to a suitable DPDK-supported VFIO/UIO driver, the HW devices will +be found as part of the device scan done at application initialization time without +the need to pass parameters to the application. + +If the device is bound to the IDXD kernel driver (and previously configured with sysfs), +then a specific work queue needs to be passed to the application via a vdev parameter. +This vdev parameter take the driver name and work queue name as parameters. +For example, to use work queue 0 on Intel\ |reg| DSA instance 0:: + + $ dpdk-test --no-pci --vdev=rawdev_idxd,wq=0.0 Once probed successfully, the device will appear as a ``rawdev``, that is a "raw device type" inside DPDK, and can be accessed using APIs from the @@ -223,6 +285,16 @@ is correct before freeing the data buffers using the returned handles: } +Filling an Area of Memory +~~~~~~~~~~~~~~~~~~~~~~~~~~ + +The IOAT driver also has support for the ``fill`` operation, where an area +of memory is overwritten, or filled, with a short pattern of data. +Fill operations can be performed in much the same was as copy operations +described above, just using the ``rte_ioat_enqueue_fill()`` function rather +than the ``rte_ioat_enqueue_copy()`` function. + + Querying Device Statistics ~~~~~~~~~~~~~~~~~~~~~~~~~~~