8. OCTEON TX SSOVF Eventdev Driver

The OCTEON TX SSOVF PMD (librte_event_octeontx) provides poll mode eventdev driver support for the inbuilt event device found in the Cavium OCTEON TX SoC family as well as their virtual functions (VF) in SR-IOV context.

More information can be found at Cavium, Inc Official Website.

8.1. Features

Features of the OCTEON TX SSOVF PMD are:

  • 64 Event queues
  • 32 Event ports
  • HW event scheduler
  • Supports 1M flows per event queue
  • Flow based event pipelining
  • Flow pinning support in flow based event pipelining
  • Queue based event pipelining
  • Supports ATOMIC, ORDERED, PARALLEL schedule types per flow
  • Event scheduling QoS based on event queue priority
  • Open system with configurable amount of outstanding events
  • HW accelerated dequeue timeout support to enable power management
  • SR-IOV VF
  • HW managed event timers support through TIMVF, with high precision and time granularity of 1us.
  • Up to 64 event timer adapters.

8.2. Supported OCTEON TX SoCs

  • CN83xx

8.3. Prerequisites

See OCTEON TX Board Support Package for setup information.

8.4. Initialization

The OCTEON TX eventdev is exposed as a vdev device which consists of a set of SSO group and work-slot PCIe VF devices. On EAL initialization, SSO PCIe VF devices will be probed and then the vdev device can be created from the application code, or from the EAL command line based on the number of probed/bound SSO PCIe VF device to DPDK by

  • Invoking rte_vdev_init("event_octeontx") from the application
  • Using --vdev="event_octeontx" in the EAL options, which will call rte_vdev_init() internally

Example:

./your_eventdev_application --vdev="event_octeontx"

8.5. Enable TIMvf stats

TIMvf stats can be enabled by using this option, by default the stats are disabled.

--vdev="event_octeontx,timvf_stats=1"

8.6. Limitations

8.6.1. Burst mode support

Burst mode is not supported. Dequeue and Enqueue functions accepts only single event at a time.

8.6.2. Rx adapter support

When eth_octeontx is used as Rx adapter event schedule type RTE_SCHED_TYPE_PARALLEL is not supported.

8.6.3. Event timer adapter support

When timvf is used as Event timer adapter the clock source mapping is as follows:

RTE_EVENT_TIMER_ADAPTER_CPU_CLK  = TIM_CLK_SRC_SCLK
RTE_EVENT_TIMER_ADAPTER_EXT_CLK0 = TIM_CLK_SRC_GPIO
RTE_EVENT_TIMER_ADAPTER_EXT_CLK1 = TIM_CLK_SRC_GTI
RTE_EVENT_TIMER_ADAPTER_EXT_CLK2 = TIM_CLK_SRC_PTP

When timvf is used as Event timer adapter event schedule type RTE_SCHED_TYPE_PARALLEL is not supported.

8.6.4. Max number of events

Max number of events in OCTEON TX Eventdev (SSO) are only limited by DRAM size and they can be configured by passing limits to kernel bootargs as follows:

ssopf.max_events=4194304

The same can be verified by looking at the following sysfs entry:

# cat /sys/module/ssopf/parameters/max_events
4194304

The maximum number of events that can be added to SSO by the event adapters such as (Rx/Timer) should be limited to the above configured value.