1.. SPDX-License-Identifier: GPL-2.0+ 2 3========================================================================== 4idpf Linux* Base Driver for the Intel(R) Infrastructure Data Path Function 5========================================================================== 6 7Intel idpf Linux driver. 8Copyright(C) 2023 Intel Corporation. 9 10.. contents:: 11 12The idpf driver serves as both the Physical Function (PF) and Virtual Function 13(VF) driver for the Intel(R) Infrastructure Data Path Function. 14 15Driver information can be obtained using ethtool, lspci, and ip. 16 17For questions related to hardware requirements, refer to the documentation 18supplied with your Intel adapter. All hardware requirements listed apply to use 19with Linux. 20 21 22Identifying Your Adapter 23======================== 24For information on how to identify your adapter, and for the latest Intel 25network drivers, refer to the Intel Support website: 26http://www.intel.com/support 27 28 29Additional Features and Configurations 30====================================== 31 32ethtool 33------- 34The driver utilizes the ethtool interface for driver configuration and 35diagnostics, as well as displaying statistical information. The latest ethtool 36version is required for this functionality. If you don't have one yet, you can 37obtain it at: 38https://kernel.org/pub/software/network/ethtool/ 39 40 41Viewing Link Messages 42--------------------- 43Link messages will not be displayed to the console if the distribution is 44restricting system messages. In order to see network driver link messages on 45your console, set dmesg to eight by entering the following:: 46 47 # dmesg -n 8 48 49.. note:: 50 This setting is not saved across reboots. 51 52 53Jumbo Frames 54------------ 55Jumbo Frames support is enabled by changing the Maximum Transmission Unit (MTU) 56to a value larger than the default value of 1500. 57 58Use the ip command to increase the MTU size. For example, enter the following 59where <ethX> is the interface number:: 60 61 # ip link set mtu 9000 dev <ethX> 62 # ip link set up dev <ethX> 63 64.. note:: 65 The maximum MTU setting for jumbo frames is 9706. This corresponds to the 66 maximum jumbo frame size of 9728 bytes. 67 68.. note:: 69 This driver will attempt to use multiple page sized buffers to receive 70 each jumbo packet. This should help to avoid buffer starvation issues when 71 allocating receive packets. 72 73.. note:: 74 Packet loss may have a greater impact on throughput when you use jumbo 75 frames. If you observe a drop in performance after enabling jumbo frames, 76 enabling flow control may mitigate the issue. 77 78 79Performance Optimization 80======================== 81Driver defaults are meant to fit a wide variety of workloads, but if further 82optimization is required, we recommend experimenting with the following 83settings. 84 85 86Interrupt Rate Limiting 87----------------------- 88This driver supports an adaptive interrupt throttle rate (ITR) mechanism that 89is tuned for general workloads. The user can customize the interrupt rate 90control for specific workloads, via ethtool, adjusting the number of 91microseconds between interrupts. 92 93To set the interrupt rate manually, you must disable adaptive mode:: 94 95 # ethtool -C <ethX> adaptive-rx off adaptive-tx off 96 97For lower CPU utilization: 98 - Disable adaptive ITR and lower Rx and Tx interrupts. The examples below 99 affect every queue of the specified interface. 100 101 - Setting rx-usecs and tx-usecs to 80 will limit interrupts to about 102 12,500 interrupts per second per queue:: 103 104 # ethtool -C <ethX> adaptive-rx off adaptive-tx off rx-usecs 80 105 tx-usecs 80 106 107For reduced latency: 108 - Disable adaptive ITR and ITR by setting rx-usecs and tx-usecs to 0 109 using ethtool:: 110 111 # ethtool -C <ethX> adaptive-rx off adaptive-tx off rx-usecs 0 112 tx-usecs 0 113 114Per-queue interrupt rate settings: 115 - The following examples are for queues 1 and 3, but you can adjust other 116 queues. 117 118 - To disable Rx adaptive ITR and set static Rx ITR to 10 microseconds or 119 about 100,000 interrupts/second, for queues 1 and 3:: 120 121 # ethtool --per-queue <ethX> queue_mask 0xa --coalesce adaptive-rx off 122 rx-usecs 10 123 124 - To show the current coalesce settings for queues 1 and 3:: 125 126 # ethtool --per-queue <ethX> queue_mask 0xa --show-coalesce 127 128 129 130Virtualized Environments 131------------------------ 132In addition to the other suggestions in this section, the following may be 133helpful to optimize performance in VMs. 134 135 - Using the appropriate mechanism (vcpupin) in the VM, pin the CPUs to 136 individual LCPUs, making sure to use a set of CPUs included in the 137 device's local_cpulist: /sys/class/net/<ethX>/device/local_cpulist. 138 139 - Configure as many Rx/Tx queues in the VM as available. (See the idpf driver 140 documentation for the number of queues supported.) For example:: 141 142 # ethtool -L <virt_interface> rx <max> tx <max> 143 144 145Support 146======= 147For general information, go to the Intel support website at: 148http://www.intel.com/support/ 149 150If an issue is identified with the released source code on a supported kernel 151with a supported adapter, email the specific information related to the issue 152to intel-wired-lan@lists.osuosl.org. 153 154 155Trademarks 156========== 157Intel is a trademark or registered trademark of Intel Corporation or its 158subsidiaries in the United States and/or other countries. 159 160* Other names and brands may be claimed as the property of others. 161