Based on kernel version 5.7.10
. Page generated on 2020-07-23 22:17 EST
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 | 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 : ($DEST_IP) destination IP -m : ($DST_MAC) destination MAC-addr -t : ($THREADS) threads to start -c : ($SKB_CLONE) SKB clones send before alloc new SKB -b : ($BURST) HW level bursting of SKBs -v : ($VERBOSE) verbose -x : ($DEBUG) debug 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. The old scripts: pktgen.conf-1-2 # 1 CPU 2 dev pktgen.conf-1-1-rdos # 1 CPU 1 dev w. route DoS pktgen.conf-1-1-ip6 # 1 CPU 1 dev ipv6 pktgen.conf-1-1-ip6-rdos # 1 CPU 1 dev ipv6 w. route DoS pktgen.conf-1-1-flows # 1 CPU 1 dev multiple flows. 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. |