X-Git-Url: http://git.droids-corp.org/?a=blobdiff_plain;ds=sidebyside;f=doc%2Fguides%2Flinux_gsg%2Fenable_func.rst;h=b2bda80bb73e3602803e843980baf317618f6914;hb=ee9586dd15fbd07d82bd674eb26b5c7bf4c309db;hp=c3fa6d35df15bc3f9335f666af5939c57014ef95;hpb=29c673401c4debc2b96d6bf4cc11f56272f9ec0e;p=dpdk.git diff --git a/doc/guides/linux_gsg/enable_func.rst b/doc/guides/linux_gsg/enable_func.rst index c3fa6d35df..b2bda80bb7 100644 --- a/doc/guides/linux_gsg/enable_func.rst +++ b/doc/guides/linux_gsg/enable_func.rst @@ -1,32 +1,5 @@ -.. BSD LICENSE - Copyright(c) 2010-2014 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. +.. SPDX-License-Identifier: BSD-3-Clause + Copyright(c) 2010-2014 Intel Corporation. .. _Enabling_Additional_Functionality: @@ -35,8 +8,8 @@ Enabling Additional Functionality .. _High_Precision_Event_Timer: -High Precision Event Timer HPET) Functionality ----------------------------------------------- +High Precision Event Timer (HPET) Functionality +----------------------------------------------- BIOS Support ~~~~~~~~~~~~ @@ -87,6 +60,14 @@ The application can then determine what action to take, if any, if the HPET is n Running DPDK Applications Without Root Privileges -------------------------------------------------------- +.. note:: + + The instructions below will allow running DPDK as non-root with older + Linux kernel versions. However, since version 4.0, the kernel does not allow + unprivileged processes to read the physical address information from + the pagemaps file, making it impossible for those processes to use HW + devices which require physical addresses + Although applications using the DPDK use network ports and other hardware resources directly, with a number of small permission adjustments it is possible to run these applications as a user other than "root". To do so, the ownership, or permissions, on the following Linux file system objects should be adjusted to ensure that @@ -176,50 +157,3 @@ Also, if ``INTEL_IOMMU_DEFAULT_ON`` is not set in the kernel, the ``intel_iommu= This ensures that the Intel IOMMU is being initialized as expected. Please note that while using ``iommu=pt`` is compulsory for ``igb_uio driver``, the ``vfio-pci`` driver can actually work with both ``iommu=pt`` and ``iommu=on``. - -High Performance of Small Packets on 40G NIC --------------------------------------------- - -As there might be firmware fixes for performance enhancement in latest version -of firmware image, the firmware update might be needed for getting high performance. -Check with the local Intel's Network Division application engineers for firmware updates. -The base driver to support firmware version of FVL3E will be integrated in the next -DPDK release, so currently the validated firmware version is 4.2.6. - -Enabling Extended Tag and Setting Max Read Request Size -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ - -PCI configurations of ``extended_tag`` and max _read_requ st_size have big impacts on performance of small packets on 40G NIC. -Enabling extended_tag and setting ``max_read_request_size`` to small size such as 128 bytes provide great helps to high performance of small packets. - -* These can be done in some BIOS implementations. - -* For other BIOS implementations, PCI configurations can be changed by using command of ``setpci``, or special configurations in DPDK config file of ``common_linux``. - - * Bits 7:5 at address of 0xA8 of each PCI device is used for setting the max_read_request_size, - and bit 8 of 0xA8 of each PCI device is used for enabling/disabling the extended_tag. - lspci and setpci can be used to read the values of 0xA8 and then write it back after being changed. - - * In config file of common_linux, below three configurations can be changed for the same purpose. - - ``CONFIG_RTE_PCI_CONFIG`` - - ``CONFIG_RTE_PCI_EXTENDED_TAG`` - - ``CONFIG_RTE_PCI_MAX_READ_REQUEST_SIZE`` - -Use 16 Bytes RX Descriptor Size -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ - -As i40e PMD supports both 16 and 32 bytes RX descriptor sizes, and 16 bytes size can provide helps to high performance of small packets. -Configuration of ``CONFIG_RTE_LIBRTE_I40E_16BYTE_RX_DESC`` in config files can be changed to use 16 bytes size RX descriptors. - -High Performance and per Packet Latency Tradeoff -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ - -Due to the hardware design, the interrupt signal inside NIC is needed for per -packet descriptor write-back. The minimum interval of interrupts could be set -at compile time by ``CONFIG_RTE_LIBRTE_I40E_ITR_INTERVAL`` in configuration files. -Though there is a default configuration, the interval could be tuned by the -users with that configuration item depends on what the user cares about more, -performance or per packet latency.