1.. SPDX-License-Identifier: GPL-2.0 2 3==================================== 4HOWTO for the linux packet generator 5==================================== 6 7Enable CONFIG_NET_PKTGEN to compile and build pktgen either in-kernel 8or as a module. A module is preferred; modprobe pktgen if needed. Once 9running, pktgen creates a thread for each CPU with affinity to that CPU. 10Monitoring and controlling is done via /proc. It is easiest to select a 11suitable sample script and configure that. 12 13On a dual CPU:: 14 15 ps aux | grep pkt 16 root 129 0.3 0.0 0 0 ? SW 2003 523:20 [kpktgend_0] 17 root 130 0.3 0.0 0 0 ? SW 2003 509:50 [kpktgend_1] 18 19 20For monitoring and control pktgen creates:: 21 22 /proc/net/pktgen/pgctrl 23 /proc/net/pktgen/kpktgend_X 24 /proc/net/pktgen/ethX 25 26 27Tuning NIC for max performance 28============================== 29 30The default NIC settings are (likely) not tuned for pktgen's artificial 31overload type of benchmarking, as this could hurt the normal use-case. 32 33Specifically increasing the TX ring buffer in the NIC:: 34 35 # ethtool -G ethX tx 1024 36 37A larger TX ring can improve pktgen's performance, while it can hurt 38in the general case, 1) because the TX ring buffer might get larger 39than the CPU's L1/L2 cache, 2) because it allows more queueing in the 40NIC HW layer (which is bad for bufferbloat). 41 42One should hesitate to conclude that packets/descriptors in the HW 43TX ring cause delay. Drivers usually delay cleaning up the 44ring-buffers for various performance reasons, and packets stalling 45the TX ring might just be waiting for cleanup. 46 47This cleanup issue is specifically the case for the driver ixgbe 48(Intel 82599 chip). This driver (ixgbe) combines TX+RX ring cleanups, 49and the cleanup interval is affected by the ethtool --coalesce setting 50of parameter "rx-usecs". 51 52For ixgbe use e.g. "30" resulting in approx 33K interrupts/sec (1/30*10^6):: 53 54 # ethtool -C ethX rx-usecs 30 55 56 57Kernel threads 58============== 59Pktgen creates a thread for each CPU with affinity to that CPU. 60Which is controlled through procfile /proc/net/pktgen/kpktgend_X. 61 62Example: /proc/net/pktgen/kpktgend_0:: 63 64 Running: 65 Stopped: eth4@0 66 Result: OK: add_device=eth4@0 67 68Most important are the devices assigned to the thread. 69 70The two basic thread commands are: 71 72 * add_device DEVICE@NAME -- adds a single device 73 * rem_device_all -- remove all associated devices 74 75When adding a device to a thread, a corresponding procfile is created 76which is used for configuring this device. Thus, device names need to 77be unique. 78 79To support adding the same device to multiple threads, which is useful 80with multi queue NICs, the device naming scheme is extended with "@": 81device@something 82 83The part after "@" can be anything, but it is custom to use the thread 84number. 85 86Viewing devices 87=============== 88 89The Params section holds configured information. The Current section 90holds running statistics. The Result is printed after a run or after 91interruption. Example:: 92 93 /proc/net/pktgen/eth4@0 94 95 Params: count 100000 min_pkt_size: 60 max_pkt_size: 60 96 frags: 0 delay: 0 clone_skb: 64 ifname: eth4@0 97 flows: 0 flowlen: 0 98 queue_map_min: 0 queue_map_max: 0 99 dst_min: 192.168.81.2 dst_max: 100 src_min: src_max: 101 src_mac: 90:e2:ba:0a:56:b4 dst_mac: 00:1b:21:3c:9d:f8 102 udp_src_min: 9 udp_src_max: 109 udp_dst_min: 9 udp_dst_max: 9 103 src_mac_count: 0 dst_mac_count: 0 104 Flags: UDPSRC_RND NO_TIMESTAMP QUEUE_MAP_CPU 105 Current: 106 pkts-sofar: 100000 errors: 0 107 started: 623913381008us stopped: 623913396439us idle: 25us 108 seq_num: 100001 cur_dst_mac_offset: 0 cur_src_mac_offset: 0 109 cur_saddr: 192.168.8.3 cur_daddr: 192.168.81.2 110 cur_udp_dst: 9 cur_udp_src: 42 111 cur_queue_map: 0 112 flows: 0 113 Result: OK: 15430(c15405+d25) usec, 100000 (60byte,0frags) 114 6480562pps 3110Mb/sec (3110669760bps) errors: 0 115 116 117Configuring devices 118=================== 119This is done via the /proc interface, and most easily done via pgset 120as defined in the sample scripts. 121You need to specify PGDEV environment variable to use functions from sample 122scripts, i.e.:: 123 124 export PGDEV=/proc/net/pktgen/eth4@0 125 source samples/pktgen/functions.sh 126 127Examples:: 128 129 pg_ctrl start starts injection. 130 pg_ctrl stop aborts injection. Also, ^C aborts generator. 131 132 pgset "clone_skb 1" sets the number of copies of the same packet 133 pgset "clone_skb 0" use single SKB for all transmits 134 pgset "burst 8" uses xmit_more API to queue 8 copies of the same 135 packet and update HW tx queue tail pointer once. 136 "burst 1" is the default 137 pgset "pkt_size 9014" sets packet size to 9014 138 pgset "frags 5" packet will consist of 5 fragments 139 pgset "count 200000" sets number of packets to send, set to zero 140 for continuous sends until explicitly stopped. 141 142 pgset "delay 5000" adds delay to hard_start_xmit(). nanoseconds 143 144 pgset "dst 10.0.0.1" sets IP destination address 145 (BEWARE! This generator is very aggressive!) 146 147 pgset "dst_min 10.0.0.1" Same as dst 148 pgset "dst_max 10.0.0.254" Set the maximum destination IP. 149 pgset "src_min 10.0.0.1" Set the minimum (or only) source IP. 150 pgset "src_max 10.0.0.254" Set the maximum source IP. 151 pgset "dst6 fec0::1" IPV6 destination address 152 pgset "src6 fec0::2" IPV6 source address 153 pgset "dstmac 00:00:00:00:00:00" sets MAC destination address 154 pgset "srcmac 00:00:00:00:00:00" sets MAC source address 155 156 pgset "queue_map_min 0" Sets the min value of tx queue interval 157 pgset "queue_map_max 7" Sets the max value of tx queue interval, for multiqueue devices 158 To select queue 1 of a given device, 159 use queue_map_min=1 and queue_map_max=1 160 161 pgset "src_mac_count 1" Sets the number of MACs we'll range through. 162 The 'minimum' MAC is what you set with srcmac. 163 164 pgset "dst_mac_count 1" Sets the number of MACs we'll range through. 165 The 'minimum' MAC is what you set with dstmac. 166 167 pgset "flag [name]" Set a flag to determine behaviour. Current flags 168 are: IPSRC_RND # IP source is random (between min/max) 169 IPDST_RND # IP destination is random 170 UDPSRC_RND, UDPDST_RND, 171 MACSRC_RND, MACDST_RND 172 TXSIZE_RND, IPV6, 173 MPLS_RND, VID_RND, SVID_RND 174 FLOW_SEQ, 175 QUEUE_MAP_RND # queue map random 176 QUEUE_MAP_CPU # queue map mirrors smp_processor_id() 177 UDPCSUM, 178 IPSEC # IPsec encapsulation (needs CONFIG_XFRM) 179 NODE_ALLOC # node specific memory allocation 180 NO_TIMESTAMP # disable timestamping 181 SHARED # enable shared SKB 182 pgset 'flag ![name]' Clear a flag to determine behaviour. 183 Note that you might need to use single quote in 184 interactive mode, so that your shell wouldn't expand 185 the specified flag as a history command. 186 187 pgset "spi [SPI_VALUE]" Set specific SA used to transform packet. 188 189 pgset "udp_src_min 9" set UDP source port min, If < udp_src_max, then 190 cycle through the port range. 191 192 pgset "udp_src_max 9" set UDP source port max. 193 pgset "udp_dst_min 9" set UDP destination port min, If < udp_dst_max, then 194 cycle through the port range. 195 pgset "udp_dst_max 9" set UDP destination port max. 196 197 pgset "mpls 0001000a,0002000a,0000000a" set MPLS labels (in this example 198 outer label=16,middle label=32, 199 inner label=0 (IPv4 NULL)) Note that 200 there must be no spaces between the 201 arguments. Leading zeros are required. 202 Do not set the bottom of stack bit, 203 that's done automatically. If you do 204 set the bottom of stack bit, that 205 indicates that you want to randomly 206 generate that address and the flag 207 MPLS_RND will be turned on. You 208 can have any mix of random and fixed 209 labels in the label stack. 210 211 pgset "mpls 0" turn off mpls (or any invalid argument works too!) 212 213 pgset "vlan_id 77" set VLAN ID 0-4095 214 pgset "vlan_p 3" set priority bit 0-7 (default 0) 215 pgset "vlan_cfi 0" set canonical format identifier 0-1 (default 0) 216 217 pgset "svlan_id 22" set SVLAN ID 0-4095 218 pgset "svlan_p 3" set priority bit 0-7 (default 0) 219 pgset "svlan_cfi 0" set canonical format identifier 0-1 (default 0) 220 221 pgset "vlan_id 9999" > 4095 remove vlan and svlan tags 222 pgset "svlan 9999" > 4095 remove svlan tag 223 224 225 pgset "tos XX" set former IPv4 TOS field (e.g. "tos 28" for AF11 no ECN, default 00) 226 pgset "traffic_class XX" set former IPv6 TRAFFIC CLASS (e.g. "traffic_class B8" for EF no ECN, default 00) 227 228 pgset "rate 300M" set rate to 300 Mb/s 229 pgset "ratep 1000000" set rate to 1Mpps 230 231 pgset "xmit_mode netif_receive" RX inject into stack netif_receive_skb() 232 Works with "burst" but not with "clone_skb". 233 Default xmit_mode is "start_xmit". 234 235Sample scripts 236============== 237 238A collection of tutorial scripts and helpers for pktgen is in the 239samples/pktgen directory. The helper parameters.sh file support easy 240and consistent parameter parsing across the sample scripts. 241 242Usage example and help:: 243 244 ./pktgen_sample01_simple.sh -i eth4 -m 00:1B:21:3C:9D:F8 -d 192.168.8.2 245 246Usage::: 247 248 ./pktgen_sample01_simple.sh [-vx] -i ethX 249 250 -i : ($DEV) output interface/device (required) 251 -s : ($PKT_SIZE) packet size 252 -d : ($DEST_IP) destination IP. CIDR (e.g. 198.18.0.0/15) is also allowed 253 -m : ($DST_MAC) destination MAC-addr 254 -p : ($DST_PORT) destination PORT range (e.g. 433-444) is also allowed 255 -t : ($THREADS) threads to start 256 -f : ($F_THREAD) index of first thread (zero indexed CPU number) 257 -c : ($SKB_CLONE) SKB clones send before alloc new SKB 258 -n : ($COUNT) num messages to send per thread, 0 means indefinitely 259 -b : ($BURST) HW level bursting of SKBs 260 -v : ($VERBOSE) verbose 261 -x : ($DEBUG) debug 262 -6 : ($IP6) IPv6 263 -w : ($DELAY) Tx Delay value (ns) 264 -a : ($APPEND) Script will not reset generator's state, but will append its config 265 266The global variables being set are also listed. E.g. the required 267interface/device parameter "-i" sets variable $DEV. Copy the 268pktgen_sampleXX scripts and modify them to fit your own needs. 269 270 271Interrupt affinity 272=================== 273Note that when adding devices to a specific CPU it is a good idea to 274also assign /proc/irq/XX/smp_affinity so that the TX interrupts are bound 275to the same CPU. This reduces cache bouncing when freeing skbs. 276 277Plus using the device flag QUEUE_MAP_CPU, which maps the SKBs TX queue 278to the running threads CPU (directly from smp_processor_id()). 279 280Enable IPsec 281============ 282Default IPsec transformation with ESP encapsulation plus transport mode 283can be enabled by simply setting:: 284 285 pgset "flag IPSEC" 286 pgset "flows 1" 287 288To avoid breaking existing testbed scripts for using AH type and tunnel mode, 289you can use "pgset spi SPI_VALUE" to specify which transformation mode 290to employ. 291 292Disable shared SKB 293================== 294By default, SKBs sent by pktgen are shared (user count > 1). 295To test with non-shared SKBs, remove the "SHARED" flag by simply setting:: 296 297 pg_set "flag !SHARED" 298 299However, if the "clone_skb" or "burst" parameters are configured, the skb 300still needs to be held by pktgen for further access. Hence the skb must be 301shared. 302 303Current commands and configuration options 304========================================== 305 306**Pgcontrol commands**:: 307 308 start 309 stop 310 reset 311 312**Thread commands**:: 313 314 add_device 315 rem_device_all 316 317 318**Device commands**:: 319 320 count 321 clone_skb 322 burst 323 debug 324 325 frags 326 delay 327 328 src_mac_count 329 dst_mac_count 330 331 pkt_size 332 min_pkt_size 333 max_pkt_size 334 335 queue_map_min 336 queue_map_max 337 skb_priority 338 339 tos (ipv4) 340 traffic_class (ipv6) 341 342 mpls 343 344 udp_src_min 345 udp_src_max 346 347 udp_dst_min 348 udp_dst_max 349 350 node 351 352 flag 353 IPSRC_RND 354 IPDST_RND 355 UDPSRC_RND 356 UDPDST_RND 357 MACSRC_RND 358 MACDST_RND 359 TXSIZE_RND 360 IPV6 361 MPLS_RND 362 VID_RND 363 SVID_RND 364 FLOW_SEQ 365 QUEUE_MAP_RND 366 QUEUE_MAP_CPU 367 UDPCSUM 368 IPSEC 369 NODE_ALLOC 370 NO_TIMESTAMP 371 SHARED 372 373 spi (ipsec) 374 375 dst_min 376 dst_max 377 378 src_min 379 src_max 380 381 dst_mac 382 src_mac 383 384 clear_counters 385 386 src6 387 dst6 388 dst6_max 389 dst6_min 390 391 flows 392 flowlen 393 394 rate 395 ratep 396 397 xmit_mode <start_xmit|netif_receive> 398 399 vlan_cfi 400 vlan_id 401 vlan_p 402 403 svlan_cfi 404 svlan_id 405 svlan_p 406 407 408References: 409 410- ftp://robur.slu.se/pub/Linux/net-development/pktgen-testing/ 411- ftp://robur.slu.se/pub/Linux/net-development/pktgen-testing/examples/ 412 413Paper from Linux-Kongress in Erlangen 2004. 414- ftp://robur.slu.se/pub/Linux/net-development/pktgen-testing/pktgen_paper.pdf 415 416Thanks to: 417 418Grant Grundler for testing on IA-64 and parisc, Harald Welte, Lennert Buytenhek 419Stephen Hemminger, Andi Kleen, Dave Miller and many others. 420 421 422Good luck with the linux net-development. 423