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+.. SPDX-License-Identifier: GPL-2.0
+
+====================================
+HOWTO for the linux packet generator
+====================================
+
+Enable CONFIG_NET_PKTGEN to compile and build pktgen either in-kernel
+or as a module. A module is preferred; modprobe pktgen if needed. Once
+running, pktgen creates a thread for each CPU with affinity to that CPU.
+Monitoring and controlling is done via /proc. It is easiest to select a
+suitable sample script and configure that.
+
+On a dual CPU::
+
+ ps aux | grep pkt
+ root 129 0.3 0.0 0 0 ? SW 2003 523:20 [kpktgend_0]
+ root 130 0.3 0.0 0 0 ? SW 2003 509:50 [kpktgend_1]
+
+
+For monitoring and control pktgen creates::
+
+ /proc/net/pktgen/pgctrl
+ /proc/net/pktgen/kpktgend_X
+ /proc/net/pktgen/ethX
+
+
+Tuning NIC for max performance
+==============================
+
+The default NIC settings are (likely) not tuned for pktgen's artificial
+overload type of benchmarking, as this could hurt the normal use-case.
+
+Specifically increasing the TX ring buffer in the NIC::
+
+ # ethtool -G ethX tx 1024
+
+A larger TX ring can improve pktgen's performance, while it can hurt
+in the general case, 1) because the TX ring buffer might get larger
+than the CPU's L1/L2 cache, 2) because it allows more queueing in the
+NIC HW layer (which is bad for bufferbloat).
+
+One should hesitate to conclude that packets/descriptors in the HW
+TX ring cause delay. Drivers usually delay cleaning up the
+ring-buffers for various performance reasons, and packets stalling
+the TX ring might just be waiting for cleanup.
+
+This cleanup issue is specifically the case for the driver ixgbe
+(Intel 82599 chip). This driver (ixgbe) combines TX+RX ring cleanups,
+and the cleanup interval is affected by the ethtool --coalesce setting
+of parameter "rx-usecs".
+
+For ixgbe use e.g. "30" resulting in approx 33K interrupts/sec (1/30*10^6)::
+
+ # ethtool -C ethX rx-usecs 30
+
+
+Kernel threads
+==============
+Pktgen creates a thread for each CPU with affinity to that CPU.
+Which is controlled through procfile /proc/net/pktgen/kpktgend_X.
+
+Example: /proc/net/pktgen/kpktgend_0::
+
+ Running:
+ Stopped: eth4@0
+ Result: OK: add_device=eth4@0
+
+Most important are the devices assigned to the thread.
+
+The two basic thread commands are:
+
+ * add_device DEVICE@NAME -- adds a single device
+ * rem_device_all -- remove all associated devices
+
+When adding a device to a thread, a corresponding procfile is created
+which is used for configuring this device. Thus, device names need to
+be unique.
+
+To support adding the same device to multiple threads, which is useful
+with multi queue NICs, the device naming scheme is extended with "@":
+device@something
+
+The part after "@" can be anything, but it is custom to use the thread
+number.
+
+Viewing devices
+===============
+
+The Params section holds configured information. The Current section
+holds running statistics. The Result is printed after a run or after
+interruption. Example::
+
+ /proc/net/pktgen/eth4@0
+
+ Params: count 100000 min_pkt_size: 60 max_pkt_size: 60
+ frags: 0 delay: 0 clone_skb: 64 ifname: eth4@0
+ flows: 0 flowlen: 0
+ queue_map_min: 0 queue_map_max: 0
+ dst_min: 192.168.81.2 dst_max:
+ src_min: src_max:
+ src_mac: 90:e2:ba:0a:56:b4 dst_mac: 00:1b:21:3c:9d:f8
+ udp_src_min: 9 udp_src_max: 109 udp_dst_min: 9 udp_dst_max: 9
+ src_mac_count: 0 dst_mac_count: 0
+ Flags: UDPSRC_RND NO_TIMESTAMP QUEUE_MAP_CPU
+ Current:
+ pkts-sofar: 100000 errors: 0
+ started: 623913381008us stopped: 623913396439us idle: 25us
+ seq_num: 100001 cur_dst_mac_offset: 0 cur_src_mac_offset: 0
+ cur_saddr: 192.168.8.3 cur_daddr: 192.168.81.2
+ cur_udp_dst: 9 cur_udp_src: 42
+ cur_queue_map: 0
+ flows: 0
+ Result: OK: 15430(c15405+d25) usec, 100000 (60byte,0frags)
+ 6480562pps 3110Mb/sec (3110669760bps) errors: 0
+
+
+Configuring devices
+===================
+This is done via the /proc interface, and most easily done via pgset
+as defined in the sample scripts.
+You need to specify PGDEV environment variable to use functions from sample
+scripts, i.e.::
+
+ export PGDEV=/proc/net/pktgen/eth4@0
+ source samples/pktgen/functions.sh
+
+Examples::
+
+ pg_ctrl start starts injection.
+ pg_ctrl stop aborts injection. Also, ^C aborts generator.
+
+ pgset "clone_skb 1" sets the number of copies of the same packet
+ pgset "clone_skb 0" use single SKB for all transmits
+ pgset "burst 8" uses xmit_more API to queue 8 copies of the same
+ packet and update HW tx queue tail pointer once.
+ "burst 1" is the default
+ pgset "pkt_size 9014" sets packet size to 9014
+ pgset "frags 5" packet will consist of 5 fragments
+ pgset "count 200000" sets number of packets to send, set to zero
+ for continuous sends until explicitly stopped.
+
+ pgset "delay 5000" adds delay to hard_start_xmit(). nanoseconds
+
+ pgset "dst 10.0.0.1" sets IP destination address
+ (BEWARE! This generator is very aggressive!)
+
+ pgset "dst_min 10.0.0.1" Same as dst
+ pgset "dst_max 10.0.0.254" Set the maximum destination IP.
+ pgset "src_min 10.0.0.1" Set the minimum (or only) source IP.
+ pgset "src_max 10.0.0.254" Set the maximum source IP.
+ pgset "dst6 fec0::1" IPV6 destination address
+ pgset "src6 fec0::2" IPV6 source address
+ pgset "dstmac 00:00:00:00:00:00" sets MAC destination address
+ pgset "srcmac 00:00:00:00:00:00" sets MAC source address
+
+ pgset "queue_map_min 0" Sets the min value of tx queue interval
+ pgset "queue_map_max 7" Sets the max value of tx queue interval, for multiqueue devices
+ To select queue 1 of a given device,
+ use queue_map_min=1 and queue_map_max=1
+
+ pgset "src_mac_count 1" Sets the number of MACs we'll range through.
+ The 'minimum' MAC is what you set with srcmac.
+
+ pgset "dst_mac_count 1" Sets the number of MACs we'll range through.
+ The 'minimum' MAC is what you set with dstmac.
+
+ pgset "flag [name]" Set a flag to determine behaviour. Current flags
+ are: IPSRC_RND # IP source is random (between min/max)
+ IPDST_RND # IP destination is random
+ UDPSRC_RND, UDPDST_RND,
+ MACSRC_RND, MACDST_RND
+ TXSIZE_RND, IPV6,
+ MPLS_RND, VID_RND, SVID_RND
+ FLOW_SEQ,
+ QUEUE_MAP_RND # queue map random
+ QUEUE_MAP_CPU # queue map mirrors smp_processor_id()
+ UDPCSUM,
+ IPSEC # IPsec encapsulation (needs CONFIG_XFRM)
+ NODE_ALLOC # node specific memory allocation
+ NO_TIMESTAMP # disable timestamping
+ pgset 'flag ![name]' Clear a flag to determine behaviour.
+ Note that you might need to use single quote in
+ interactive mode, so that your shell wouldn't expand
+ the specified flag as a history command.
+
+ pgset "spi [SPI_VALUE]" Set specific SA used to transform packet.
+
+ pgset "udp_src_min 9" set UDP source port min, If < udp_src_max, then
+ cycle through the port range.
+
+ pgset "udp_src_max 9" set UDP source port max.
+ pgset "udp_dst_min 9" set UDP destination port min, If < udp_dst_max, then
+ cycle through the port range.
+ pgset "udp_dst_max 9" set UDP destination port max.
+
+ pgset "mpls 0001000a,0002000a,0000000a" set MPLS labels (in this example
+ outer label=16,middle label=32,
+ inner label=0 (IPv4 NULL)) Note that
+ there must be no spaces between the
+ arguments. Leading zeros are required.
+ Do not set the bottom of stack bit,
+ that's done automatically. If you do
+ set the bottom of stack bit, that
+ indicates that you want to randomly
+ generate that address and the flag
+ MPLS_RND will be turned on. You
+ can have any mix of random and fixed
+ labels in the label stack.
+
+ pgset "mpls 0" turn off mpls (or any invalid argument works too!)
+
+ pgset "vlan_id 77" set VLAN ID 0-4095
+ pgset "vlan_p 3" set priority bit 0-7 (default 0)
+ pgset "vlan_cfi 0" set canonical format identifier 0-1 (default 0)
+
+ pgset "svlan_id 22" set SVLAN ID 0-4095
+ pgset "svlan_p 3" set priority bit 0-7 (default 0)
+ pgset "svlan_cfi 0" set canonical format identifier 0-1 (default 0)
+
+ pgset "vlan_id 9999" > 4095 remove vlan and svlan tags
+ pgset "svlan 9999" > 4095 remove svlan tag
+
+
+ pgset "tos XX" set former IPv4 TOS field (e.g. "tos 28" for AF11 no ECN, default 00)
+ pgset "traffic_class XX" set former IPv6 TRAFFIC CLASS (e.g. "traffic_class B8" for EF no ECN, default 00)
+
+ pgset "rate 300M" set rate to 300 Mb/s
+ pgset "ratep 1000000" set rate to 1Mpps
+
+ pgset "xmit_mode netif_receive" RX inject into stack netif_receive_skb()
+ Works with "burst" but not with "clone_skb".
+ Default xmit_mode is "start_xmit".
+
+Sample scripts
+==============
+
+A collection of tutorial scripts and helpers for pktgen is in the
+samples/pktgen directory. The helper parameters.sh file support easy
+and consistent parameter parsing across the sample scripts.
+
+Usage example and help::
+
+ ./pktgen_sample01_simple.sh -i eth4 -m 00:1B:21:3C:9D:F8 -d 192.168.8.2
+
+Usage:::
+
+ ./pktgen_sample01_simple.sh [-vx] -i ethX
+
+ -i : ($DEV) output interface/device (required)
+ -s : ($PKT_SIZE) packet size
+ -d : ($DEST_IP) destination IP. CIDR (e.g. 198.18.0.0/15) is also allowed
+ -m : ($DST_MAC) destination MAC-addr
+ -p : ($DST_PORT) destination PORT range (e.g. 433-444) is also allowed
+ -t : ($THREADS) threads to start
+ -f : ($F_THREAD) index of first thread (zero indexed CPU number)
+ -c : ($SKB_CLONE) SKB clones send before alloc new SKB
+ -n : ($COUNT) num messages to send per thread, 0 means indefinitely
+ -b : ($BURST) HW level bursting of SKBs
+ -v : ($VERBOSE) verbose
+ -x : ($DEBUG) debug
+ -6 : ($IP6) IPv6
+ -w : ($DELAY) Tx Delay value (ns)
+ -a : ($APPEND) Script will not reset generator's state, but will append its config
+
+The global variables being set are also listed. E.g. the required
+interface/device parameter "-i" sets variable $DEV. Copy the
+pktgen_sampleXX scripts and modify them to fit your own needs.
+
+
+Interrupt affinity
+===================
+Note that when adding devices to a specific CPU it is a good idea to
+also assign /proc/irq/XX/smp_affinity so that the TX interrupts are bound
+to the same CPU. This reduces cache bouncing when freeing skbs.
+
+Plus using the device flag QUEUE_MAP_CPU, which maps the SKBs TX queue
+to the running threads CPU (directly from smp_processor_id()).
+
+Enable IPsec
+============
+Default IPsec transformation with ESP encapsulation plus transport mode
+can be enabled by simply setting::
+
+ pgset "flag IPSEC"
+ pgset "flows 1"
+
+To avoid breaking existing testbed scripts for using AH type and tunnel mode,
+you can use "pgset spi SPI_VALUE" to specify which transformation mode
+to employ.
+
+
+Current commands and configuration options
+==========================================
+
+**Pgcontrol commands**::
+
+ start
+ stop
+ reset
+
+**Thread commands**::
+
+ add_device
+ rem_device_all
+
+
+**Device commands**::
+
+ count
+ clone_skb
+ burst
+ debug
+
+ frags
+ delay
+
+ src_mac_count
+ dst_mac_count
+
+ pkt_size
+ min_pkt_size
+ max_pkt_size
+
+ queue_map_min
+ queue_map_max
+ skb_priority
+
+ tos (ipv4)
+ traffic_class (ipv6)
+
+ mpls
+
+ udp_src_min
+ udp_src_max
+
+ udp_dst_min
+ udp_dst_max
+
+ node
+
+ flag
+ IPSRC_RND
+ IPDST_RND
+ UDPSRC_RND
+ UDPDST_RND
+ MACSRC_RND
+ MACDST_RND
+ TXSIZE_RND
+ IPV6
+ MPLS_RND
+ VID_RND
+ SVID_RND
+ FLOW_SEQ
+ QUEUE_MAP_RND
+ QUEUE_MAP_CPU
+ UDPCSUM
+ IPSEC
+ NODE_ALLOC
+ NO_TIMESTAMP
+
+ spi (ipsec)
+
+ dst_min
+ dst_max
+
+ src_min
+ src_max
+
+ dst_mac
+ src_mac
+
+ clear_counters
+
+ src6
+ dst6
+ dst6_max
+ dst6_min
+
+ flows
+ flowlen
+
+ rate
+ ratep
+
+ xmit_mode <start_xmit|netif_receive>
+
+ vlan_cfi
+ vlan_id
+ vlan_p
+
+ svlan_cfi
+ svlan_id
+ svlan_p
+
+
+References:
+
+- ftp://robur.slu.se/pub/Linux/net-development/pktgen-testing/
+- ftp://robur.slu.se/pub/Linux/net-development/pktgen-testing/examples/
+
+Paper from Linux-Kongress in Erlangen 2004.
+- ftp://robur.slu.se/pub/Linux/net-development/pktgen-testing/pktgen_paper.pdf
+
+Thanks to:
+
+Grant Grundler for testing on IA-64 and parisc, Harald Welte, Lennert Buytenhek
+Stephen Hemminger, Andi Kleen, Dave Miller and many others.
+
+
+Good luck with the linux net-development.