Documentation/networking/pktgen.txt

   1
   2
   3                   HOWTO for the linux packet generator
   4                   ------------------------------------
   5
   6 Date: 041221
   7
   8 Enable CONFIG_NET_PKTGEN to compile and build pktgen.o either in kernel
   9 or as module. Module is preferred. insmod pktgen if needed. Once running
  10 pktgen creates a thread on each CPU where each thread has affinity to its CPU.
  11 Monitoring and controlling is done via /proc. Easiest to select a suitable
  12 a sample script and configure.
  13
  14 On a dual CPU:
  15
  16 ps aux | grep pkt
  17 root       129  0.3  0.0     0    0 ?        SW    2003 523:20 [pktgen/0]
  18 root       130  0.3  0.0     0    0 ?        SW    2003 509:50 [pktgen/1]
  19
  20
  21 For monitoring and control pktgen creates:
  22         /proc/net/pktgen/pgctrl
  23         /proc/net/pktgen/kpktgend_X
  24         /proc/net/pktgen/ethX
  25
  26
  27 Tuning NIC for max performance
  28 ==============================
  29
  30 The default NIC setting are (likely) not tuned for pktgen's artificial
  31 overload type of benchmarking, as this could hurt the normal use-case.
  32
  33 Specifically increasing the TX ring buffer in the NIC:
  34  # ethtool -G ethX tx 1024
  35
  36 A larger TX ring can improve pktgen's performance, while it can hurt
  37 in the general case, 1) because the TX ring buffer might get larger
  38 than the CPUs L1/L2 cache, 2) because it allow more queueing in the
  39 NIC HW layer (which is bad for bufferbloat).
  40
  41 One should be careful to conclude, that packets/descriptors in the HW
  42 TX ring cause delay.  Drivers usually delay cleaning up the
  43 ring-buffers (for various performance reasons), thus packets stalling
  44 the TX ring, might just be waiting for cleanup.
  45
  46 This cleanup issues is specifically the case, for the driver ixgbe
  47 (Intel 82599 chip).  This driver (ixgbe) combine TX+RX ring cleanups,
  48 and the cleanup interval is affected by the ethtool --coalesce setting
  49 of parameter "rx-usecs".
  50
  51 For ixgbe use e.g "30" resulting in approx 33K interrupts/sec (1/30*10^6):
  52  # ethtool -C ethX rx-usecs 30
  53
  54
  55 Viewing threads
  56 ===============
  57 /proc/net/pktgen/kpktgend_0
  58 Name: kpktgend_0  max_before_softirq: 10000
  59 Running:
  60 Stopped: eth1
  61 Result: OK: max_before_softirq=10000
  62
  63 Most important the devices assigned to thread. Note! A device can only belong
  64 to one thread.
  65
  66
  67 Viewing devices
  68 ===============
  69
  70 Parm section holds configured info. Current hold running stats.
  71 Result is printed after run or after interruption. Example:
  72
  73 /proc/net/pktgen/eth1
  74
  75 Params: count 10000000  min_pkt_size: 60  max_pkt_size: 60
  76      frags: 0  delay: 0  clone_skb: 1000000  ifname: eth1
  77      flows: 0 flowlen: 0
  78      dst_min: 10.10.11.2  dst_max:
  79      src_min:   src_max:
  80      src_mac: 00:00:00:00:00:00  dst_mac: 00:04:23:AC:FD:82
  81      udp_src_min: 9  udp_src_max: 9  udp_dst_min: 9  udp_dst_max: 9
  82      src_mac_count: 0  dst_mac_count: 0
  83      Flags:
  84 Current:
  85      pkts-sofar: 10000000  errors: 39664
  86      started: 1103053986245187us  stopped: 1103053999346329us idle: 880401us
  87      seq_num: 10000011  cur_dst_mac_offset: 0  cur_src_mac_offset: 0
  88      cur_saddr: 0x10a0a0a  cur_daddr: 0x20b0a0a
  89      cur_udp_dst: 9  cur_udp_src: 9
  90      flows: 0
  91 Result: OK: 13101142(c12220741+d880401) usec, 10000000 (60byte,0frags)
  92   763292pps 390Mb/sec (390805504bps) errors: 39664
  93
  94 Configuring threads and devices
  95 ================================
  96 This is done via the /proc interface easiest done via pgset in 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 examples dir.
 199
 200 pktgen.conf-1-1                  # 1 CPU 1 dev
 201 pktgen.conf-1-2                  # 1 CPU 2 dev
 202 pktgen.conf-2-1                  # 2 CPU's 1 dev
 203 pktgen.conf-2-2                  # 2 CPU's 2 dev
 204 pktgen.conf-1-1-rdos             # 1 CPU 1 dev w. route DoS
 205 pktgen.conf-1-1-ip6              # 1 CPU 1 dev ipv6
 206 pktgen.conf-1-1-ip6-rdos         # 1 CPU 1 dev ipv6  w. route DoS
 207 pktgen.conf-1-1-flows            # 1 CPU 1 dev multiple flows.
 208
 209 Run in shell: ./pktgen.conf-X-Y It does all the setup including sending.
 210
 211
 212 Interrupt affinity
 213 ===================
 214 Note when adding devices to a specific CPU there good idea to also assign
 215 /proc/irq/XX/smp_affinity so the TX-interrupts gets bound to the same CPU.
 216 as this reduces cache bouncing when freeing skb's.
 217
 218 Enable IPsec
 219 ============
 220 Default IPsec transformation with ESP encapsulation plus Transport mode
 221 could be enabled by simply setting:
 222
 223 pgset "flag IPSEC"
 224 pgset "flows 1"
 225
 226 To avoid breaking existing testbed scripts for using AH type and tunnel mode,
 227 user could use "pgset spi SPI_VALUE" to specify which formal of transformation
 228 to employ.
 229
 230
 231 Current commands and configuration options
 232 ==========================================
 233
 234 ** Pgcontrol commands:
 235
 236 start
 237 stop
 238
 239 ** Thread commands:
 240
 241 add_device
 242 rem_device_all
 243 max_before_softirq
 244
 245
 246 ** Device commands:
 247
 248 count
 249 clone_skb
 250 debug
 251
 252 frags
 253 delay
 254
 255 src_mac_count
 256 dst_mac_count
 257
 258 pkt_size
 259 min_pkt_size
 260 max_pkt_size
 261
 262 mpls
 263
 264 udp_src_min
 265 udp_src_max
 266
 267 udp_dst_min
 268 udp_dst_max
 269
 270 flag
 271   IPSRC_RND
 272   IPDST_RND
 273   UDPSRC_RND
 274   UDPDST_RND
 275   MACSRC_RND
 276   MACDST_RND
 277   TXSIZE_RND
 278   IPV6
 279   MPLS_RND
 280   VID_RND
 281   SVID_RND
 282   FLOW_SEQ
 283   QUEUE_MAP_RND
 284   QUEUE_MAP_CPU
 285   UDPCSUM
 286   IPSEC
 287   NODE_ALLOC
 288
 289 dst_min
 290 dst_max
 291
 292 src_min
 293 src_max
 294
 295 dst_mac
 296 src_mac
 297
 298 clear_counters
 299
 300 dst6
 301 src6
 302
 303 flows
 304 flowlen
 305
 306 rate
 307 ratep
 308
 309 References:
 310 ftp://robur.slu.se/pub/Linux/net-development/pktgen-testing/
 311 ftp://robur.slu.se/pub/Linux/net-development/pktgen-testing/examples/
 312
 313 Paper from Linux-Kongress in Erlangen 2004.
 314 ftp://robur.slu.se/pub/Linux/net-development/pktgen-testing/pktgen_paper.pdf
 315
 316 Thanks to:
 317 Grant Grundler for testing on IA-64 and parisc, Harald Welte,  Lennert Buytenhek
 318 Stephen Hemminger, Andi Kleen, Dave Miller and many others.
 319
 320
 321 Good luck with the linux net-development.