| |
| |
| 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 [pktgen/0] |
| root 130 0.3 0.0 0 0 ? SW 2003 509:50 [pktgen/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 corrosponding 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, a 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. |
| |
| Examples: |
| |
| 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 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 stop aborts injection. Also, ^C aborts generator. |
| |
| 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 consistant 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. |
