Message ID | 1548403828-31870-6-git-send-email-mk@semihalf.com (mailing list archive) |
---|---|
State | Accepted, archived |
Delegated to: | Ferruh Yigit |
Headers | |
Series | net/ena: minor fixes and docs update | |
Checks
Context | Check | Description |
---|---|---|
ci/checkpatch | success | coding style OK |
ci/Intel-compilation | success | Compilation OK |
Commit Message
diff --git a/doc/guides/nics/ena.rst b/doc/guides/nics/ena.rst index 9f0a650..80da4b6 100644 --- a/doc/guides/nics/ena.rst +++ b/doc/guides/nics/ena.rst @@ -183,10 +183,22 @@ Prerequisites #. Prepare the system as recommended by DPDK suite. This includes environment variables, hugepages configuration, tool-chains and configuration. -#. ENA PMD can operate with ``vfio-pci`` or ``igb_uio`` driver. +#. ENA PMD can operate with ``vfio-pci``(*) or ``igb_uio`` driver. + + (*) ENAv2 hardware supports Low Latency Queue v2 (LLQv2). This feature + reduces the latency of the packets by pushing the header directly through + the PCI to the device, before the DMA is even triggered. For proper work + kernel PCI driver must support write combining (WC). In mainline version of + ``igb_uio`` (in DPDK repo) it must be enabled by loding module with + ``wc_activate=1`` flag (example below). However, mainline's vfio-pci + driver in kernel doesn't have WC support yet (planed to be added). + If vfio-pci used user should be either turn off ENAv2 (to avoid performance + impact) or recompile vfio-pci driver with patch provided in + `amzn-github <https://github.com/amzn/amzn-drivers/tree/master/userspace/dpdk/enav2-vfio-patch>`_. #. Insert ``vfio-pci`` or ``igb_uio`` kernel module using the command - ``modprobe vfio-pci`` or ``modprobe igb_uio`` respectively. + ``modprobe vfio-pci`` or ``modprobe uio; insmod igb_uio.ko wc_activate=1`` + respectively. #. For ``vfio-pci`` users only: Please make sure that ``IOMMU`` is enabled in your system,