Documentation/networking/pktgen.txt

   1
   2
   3                   HOWTO for the linux packet generator
   4                   ------------------------------------
   5
   6 Enable CONFIG_NET_PKTGEN to compile and build pktgen.o either in-kernel
   7 or as a module.  A module is preferred; insmod pktgen if needed.  Once
   8 running, pktgen creates a thread for each CPU with affinity to that CPU.
   9 Monitoring and controlling is done via /proc.  It is easiest to select a
  10 suitable sample script and configure that.
  11
  12 On a dual CPU:
  13
  14 ps aux | grep pkt
  15 root       129  0.3  0.0     0    0 ?        SW    2003 523:20 [pktgen/0]
  16 root       130  0.3  0.0     0    0 ?        SW    2003 509:50 [pktgen/1]
  17
  18
  19 For monitoring and control pktgen creates:
  20         /proc/net/pktgen/pgctrl
  21         /proc/net/pktgen/kpktgend_X
  22         /proc/net/pktgen/ethX
  23
  24
  25 Tuning NIC for max performance
  26 ==============================
  27
  28 The default NIC settings are (likely) not tuned for pktgen's artificial
  29 overload type of benchmarking, as this could hurt the normal use-case.
  30
  31 Specifically increasing the TX ring buffer in the NIC:
  32  # ethtool -G ethX tx 1024
  33
  34 A larger TX ring can improve pktgen's performance, while it can hurt
  35 in the general case, 1) because the TX ring buffer might get larger
  36 than the CPU's L1/L2 cache, 2) because it allows more queueing in the
  37 NIC HW layer (which is bad for bufferbloat).
  38
  39 One should hesitate to conclude that packets/descriptors in the HW
  40 TX ring cause delay.  Drivers usually delay cleaning up the
  41 ring-buffers for various performance reasons, and packets stalling
  42 the TX ring might just be waiting for cleanup.
  43
  44 This cleanup issue is specifically the case for the driver ixgbe
  45 (Intel 82599 chip).  This driver (ixgbe) combines TX+RX ring cleanups,
  46 and the cleanup interval is affected by the ethtool --coalesce setting
  47 of parameter "rx-usecs".
  48
  49 For ixgbe use e.g. "30" resulting in approx 33K interrupts/sec (1/30*10^6):
  50  # ethtool -C ethX rx-usecs 30
  51
  52
  53 Viewing threads
  54 ===============
  55 /proc/net/pktgen/kpktgend_0
  56 Name: kpktgend_0  max_before_softirq: 10000
  57 Running:
  58 Stopped: eth1
  59 Result: OK: max_before_softirq=10000
  60
  61 Most important are the devices assigned to the thread.  Note that a
  62 device can only belong to one thread.
  63
  64
  65 Viewing devices
  66 ===============
  67
  68 The Params section holds configured information.  The Current section
  69 holds running statistics.  The Result is printed after a run or after
  70 interruption.  Example:
  71
  72 /proc/net/pktgen/eth1
  73
  74 Params: count 10000000  min_pkt_size: 60  max_pkt_size: 60
  75      frags: 0  delay: 0  clone_skb: 1000000  ifname: eth1
  76      flows: 0 flowlen: 0
  77      dst_min: 10.10.11.2  dst_max:
  78      src_min:   src_max:
  79      src_mac: 00:00:00:00:00:00  dst_mac: 00:04:23:AC:FD:82
  80      udp_src_min: 9  udp_src_max: 9  udp_dst_min: 9  udp_dst_max: 9
  81      src_mac_count: 0  dst_mac_count: 0
  82      Flags:
  83 Current:
  84      pkts-sofar: 10000000  errors: 39664
  85      started: 1103053986245187us  stopped: 1103053999346329us idle: 880401us
  86      seq_num: 10000011  cur_dst_mac_offset: 0  cur_src_mac_offset: 0
  87      cur_saddr: 0x10a0a0a  cur_daddr: 0x20b0a0a
  88      cur_udp_dst: 9  cur_udp_src: 9
  89      flows: 0
  90 Result: OK: 13101142(c12220741+d880401) usec, 10000000 (60byte,0frags)
  91   763292pps 390Mb/sec (390805504bps) errors: 39664
  92
  93 Configuring threads and devices
  94 ================================
  95 This is done via the /proc interface, and most easily done via pgset in
  96 the scripts.
  97
  98 Examples:
  99
 100  pgset "clone_skb 1"     sets the number of copies of the same packet
 101  pgset "clone_skb 0"     use single SKB for all transmits
 102  pgset "burst 8"         uses xmit_more API to queue 8 copies of the same
 103                          packet and update HW tx queue tail pointer once.
 104                          "burst 1" is the default
 105  pgset "pkt_size 9014"   sets packet size to 9014
 106  pgset "frags 5"         packet will consist of 5 fragments
 107  pgset "count 200000"    sets number of packets to send, set to zero
 108                          for continuous sends until explicitly stopped.
 109
 110  pgset "delay 5000"      adds delay to hard_start_xmit(). nanoseconds
 111
 112  pgset "dst 10.0.0.1"    sets IP destination address
 113                          (BEWARE! This generator is very aggressive!)
 114
 115  pgset "dst_min 10.0.0.1"            Same as dst
 116  pgset "dst_max 10.0.0.254"          Set the maximum destination IP.
 117  pgset "src_min 10.0.0.1"            Set the minimum (or only) source IP.
 118  pgset "src_max 10.0.0.254"          Set the maximum source IP.
 119  pgset "dst6 fec0::1"     IPV6 destination address
 120  pgset "src6 fec0::2"     IPV6 source address
 121  pgset "dstmac 00:00:00:00:00:00"    sets MAC destination address
 122  pgset "srcmac 00:00:00:00:00:00"    sets MAC source address
 123
 124  pgset "queue_map_min 0" Sets the min value of tx queue interval
 125  pgset "queue_map_max 7" Sets the max value of tx queue interval, for multiqueue devices
 126                          To select queue 1 of a given device,
 127                          use queue_map_min=1 and queue_map_max=1
 128
 129  pgset "src_mac_count 1" Sets the number of MACs we'll range through.
 130                          The 'minimum' MAC is what you set with srcmac.
 131
 132  pgset "dst_mac_count 1" Sets the number of MACs we'll range through.
 133                          The 'minimum' MAC is what you set with dstmac.
 134
 135  pgset "flag [name]"     Set a flag to determine behaviour.  Current flags
 136                          are: IPSRC_RND # IP source is random (between min/max)
 137                               IPDST_RND # IP destination is random
 138                               UDPSRC_RND, UDPDST_RND,
 139                               MACSRC_RND, MACDST_RND
 140                               TXSIZE_RND, IPV6,
 141                               MPLS_RND, VID_RND, SVID_RND
 142                               FLOW_SEQ,
 143                               QUEUE_MAP_RND # queue map random
 144                               QUEUE_MAP_CPU # queue map mirrors smp_processor_id()
 145                               UDPCSUM,
 146                               IPSEC # IPsec encapsulation (needs CONFIG_XFRM)
 147                               NODE_ALLOC # node specific memory allocation
 148
 149  pgset spi SPI_VALUE     Set specific SA used to transform packet.
 150
 151  pgset "udp_src_min 9"   set UDP source port min, If < udp_src_max, then
 152                          cycle through the port range.
 153
 154  pgset "udp_src_max 9"   set UDP source port max.
 155  pgset "udp_dst_min 9"   set UDP destination port min, If < udp_dst_max, then
 156                          cycle through the port range.
 157  pgset "udp_dst_max 9"   set UDP destination port max.
 158
 159  pgset "mpls 0001000a,0002000a,0000000a" set MPLS labels (in this example
 160                                          outer label=16,middle label=32,
 161                                          inner label=0 (IPv4 NULL)) Note that
 162                                          there must be no spaces between the
 163                                          arguments. Leading zeros are required.
 164                                          Do not set the bottom of stack bit,
 165                                          that's done automatically. If you do
 166                                          set the bottom of stack bit, that
 167                                          indicates that you want to randomly
 168                                          generate that address and the flag
 169                                          MPLS_RND will be turned on. You
 170                                          can have any mix of random and fixed
 171                                          labels in the label stack.
 172
 173  pgset "mpls 0"           turn off mpls (or any invalid argument works too!)
 174
 175  pgset "vlan_id 77"       set VLAN ID 0-4095
 176  pgset "vlan_p 3"         set priority bit 0-7 (default 0)
 177  pgset "vlan_cfi 0"       set canonical format identifier 0-1 (default 0)
 178
 179  pgset "svlan_id 22"      set SVLAN ID 0-4095
 180  pgset "svlan_p 3"        set priority bit 0-7 (default 0)
 181  pgset "svlan_cfi 0"      set canonical format identifier 0-1 (default 0)
 182
 183  pgset "vlan_id 9999"     > 4095 remove vlan and svlan tags
 184  pgset "svlan 9999"       > 4095 remove svlan tag
 185
 186
 187  pgset "tos XX"           set former IPv4 TOS field (e.g. "tos 28" for AF11 no ECN, default 00)
 188  pgset "traffic_class XX" set former IPv6 TRAFFIC CLASS (e.g. "traffic_class B8" for EF no ECN, default 00)
 189
 190  pgset stop               aborts injection. Also, ^C aborts generator.
 191
 192  pgset "rate 300M"        set rate to 300 Mb/s
 193  pgset "ratep 1000000"    set rate to 1Mpps
 194
 195 Example scripts
 196 ===============
 197
 198 A collection of small tutorial scripts for pktgen is in the examples
 199 directory:
 200
 201 pktgen.conf-1-1                  # 1 CPU 1 dev
 202 pktgen.conf-1-2                  # 1 CPU 2 dev
 203 pktgen.conf-2-1                  # 2 CPU's 1 dev
 204 pktgen.conf-2-2                  # 2 CPU's 2 dev
 205 pktgen.conf-1-1-rdos             # 1 CPU 1 dev w. route DoS
 206 pktgen.conf-1-1-ip6              # 1 CPU 1 dev ipv6
 207 pktgen.conf-1-1-ip6-rdos         # 1 CPU 1 dev ipv6  w. route DoS
 208 pktgen.conf-1-1-flows            # 1 CPU 1 dev multiple flows.
 209
 210 Run in shell: ./pktgen.conf-X-Y
 211 This does all the setup including sending.
 212
 213
 214 Interrupt affinity
 215 ===================
 216 Note that when adding devices to a specific CPU it is a good idea to
 217 also assign /proc/irq/XX/smp_affinity so that the TX interrupts are bound
 218 to the same CPU.  This reduces cache bouncing when freeing skbs.
 219
 220 Enable IPsec
 221 ============
 222 Default IPsec transformation with ESP encapsulation plus transport mode
 223 can be enabled by simply setting:
 224
 225 pgset "flag IPSEC"
 226 pgset "flows 1"
 227
 228 To avoid breaking existing testbed scripts for using AH type and tunnel mode,
 229 you can use "pgset spi SPI_VALUE" to specify which transformation mode
 230 to employ.
 231
 232
 233 Current commands and configuration options
 234 ==========================================
 235
 236 ** Pgcontrol commands:
 237
 238 start
 239 stop
 240
 241 ** Thread commands:
 242
 243 add_device
 244 rem_device_all
 245 max_before_softirq
 246
 247
 248 ** Device commands:
 249
 250 count
 251 clone_skb
 252 debug
 253
 254 frags
 255 delay
 256
 257 src_mac_count
 258 dst_mac_count
 259
 260 pkt_size
 261 min_pkt_size
 262 max_pkt_size
 263
 264 mpls
 265
 266 udp_src_min
 267 udp_src_max
 268
 269 udp_dst_min
 270 udp_dst_max
 271
 272 flag
 273   IPSRC_RND
 274   IPDST_RND
 275   UDPSRC_RND
 276   UDPDST_RND
 277   MACSRC_RND
 278   MACDST_RND
 279   TXSIZE_RND
 280   IPV6
 281   MPLS_RND
 282   VID_RND
 283   SVID_RND
 284   FLOW_SEQ
 285   QUEUE_MAP_RND
 286   QUEUE_MAP_CPU
 287   UDPCSUM
 288   IPSEC
 289   NODE_ALLOC
 290
 291 dst_min
 292 dst_max
 293
 294 src_min
 295 src_max
 296
 297 dst_mac
 298 src_mac
 299
 300 clear_counters
 301
 302 dst6
 303 src6
 304
 305 flows
 306 flowlen
 307
 308 rate
 309 ratep
 310
 311 References:
 312 ftp://robur.slu.se/pub/Linux/net-development/pktgen-testing/
 313 ftp://robur.slu.se/pub/Linux/net-development/pktgen-testing/examples/
 314
 315 Paper from Linux-Kongress in Erlangen 2004.
 316 ftp://robur.slu.se/pub/Linux/net-development/pktgen-testing/pktgen_paper.pdf
 317
 318 Thanks to:
 319 Grant Grundler for testing on IA-64 and parisc, Harald Welte,  Lennert Buytenhek
 320 Stephen Hemminger, Andi Kleen, Dave Miller and many others.
 321
 322
 323 Good luck with the linux net-development.