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diff --git a/Documentation/networking/multiqueue.txt b/Documentation/networking/multiqueue.txt deleted file mode 100644 index 4caa0e314cc2..000000000000 --- a/Documentation/networking/multiqueue.txt +++ /dev/null @@ -1,79 +0,0 @@ - - HOWTO for multiqueue network device support - =========================================== - -Section 1: Base driver requirements for implementing multiqueue support - -Intro: Kernel support for multiqueue devices ---------------------------------------------------------- - -Kernel support for multiqueue devices is always present. - -Section 1: Base driver requirements for implementing multiqueue support ------------------------------------------------------------------------ - -Base drivers are required to use the new alloc_etherdev_mq() or -alloc_netdev_mq() functions to allocate the subqueues for the device. The -underlying kernel API will take care of the allocation and deallocation of -the subqueue memory, as well as netdev configuration of where the queues -exist in memory. - -The base driver will also need to manage the queues as it does the global -netdev->queue_lock today. Therefore base drivers should use the -netif_{start|stop|wake}_subqueue() functions to manage each queue while the -device is still operational. netdev->queue_lock is still used when the device -comes online or when it's completely shut down (unregister_netdev(), etc.). - - -Section 2: Qdisc support for multiqueue devices - ------------------------------------------------ - -Currently two qdiscs are optimized for multiqueue devices. The first is the -default pfifo_fast qdisc. This qdisc supports one qdisc per hardware queue. -A new round-robin qdisc, sch_multiq also supports multiple hardware queues. The -qdisc is responsible for classifying the skb's and then directing the skb's to -bands and queues based on the value in skb->queue_mapping. Use this field in -the base driver to determine which queue to send the skb to. - -sch_multiq has been added for hardware that wishes to avoid head-of-line -blocking. It will cycle though the bands and verify that the hardware queue -associated with the band is not stopped prior to dequeuing a packet. - -On qdisc load, the number of bands is based on the number of queues on the -hardware. Once the association is made, any skb with skb->queue_mapping set, -will be queued to the band associated with the hardware queue. - - -Section 3: Brief howto using MULTIQ for multiqueue devices ---------------------------------------------------------------- - -The userspace command 'tc,' part of the iproute2 package, is used to configure -qdiscs. To add the MULTIQ qdisc to your network device, assuming the device -is called eth0, run the following command: - -# tc qdisc add dev eth0 root handle 1: multiq - -The qdisc will allocate the number of bands to equal the number of queues that -the device reports, and bring the qdisc online. Assuming eth0 has 4 Tx -queues, the band mapping would look like: - -band 0 => queue 0 -band 1 => queue 1 -band 2 => queue 2 -band 3 => queue 3 - -Traffic will begin flowing through each queue based on either the simple_tx_hash -function or based on netdev->select_queue() if you have it defined. - -The behavior of tc filters remains the same. However a new tc action, -skbedit, has been added. Assuming you wanted to route all traffic to a -specific host, for example 192.168.0.3, through a specific queue you could use -this action and establish a filter such as: - -tc filter add dev eth0 parent 1: protocol ip prio 1 u32 \ - match ip dst 192.168.0.3 \ - action skbedit queue_mapping 3 - -Author: Alexander Duyck <alexander.h.duyck@intel.com> -Original Author: Peter P. Waskiewicz Jr. <peter.p.waskiewicz.jr@intel.com> |