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9ceb87fcea
Using pktgen I'm seeing the ixgbe driver "push-back", due TX ring
running full. Thus, the TX ring is artificially limiting pktgen.
(Diagnose via "ethtool -S", look for "tx_restart_queue" or "tx_busy"
counters.)
Using ixgbe, the real reason behind the TX ring running full, is due
to TX ring not being cleaned up fast enough. The ixgbe driver combines
TX+RX ring cleanups, and the cleanup interval is affected by the
ethtool --coalesce setting of parameter "rx-usecs".
Do not increase the default NIC TX ring buffer or default cleanup
interval. Instead simply document that pktgen needs special NIC
tuning for maximum packet per sec performance.
Performance results with pktgen with clone_skb=100000.
TX ring size 512 (default), adjusting "rx-usecs":
(Single CPU performance, E5-2630, ixgbe)
- 3935002 pps - rx-usecs: 1 (irqs: 9346)
- 5132350 pps - rx-usecs: 10 (irqs: 99157)
- 5375111 pps - rx-usecs: 20 (irqs: 50154)
- 5454050 pps - rx-usecs: 30 (irqs: 33872)
- 5496320 pps - rx-usecs: 40 (irqs: 26197)
- 5502510 pps - rx-usecs: 50 (irqs: 21527)
TX ring size adjusting (ethtool -G), "rx-usecs==1" (default):
- 3935002 pps - tx-size: 512
- 5354401 pps - tx-size: 768
- 5356847 pps - tx-size: 1024
- 5327595 pps - tx-size: 1536
- 5356779 pps - tx-size: 2048
- 5353438 pps - tx-size: 4096
Notice after commit 6f25cd47d (pktgen: fix xmit test for BQL enabled
devices) pktgen uses netif_xmit_frozen_or_drv_stopped() and ignores
the BQL "stack" pause (QUEUE_STATE_STACK_XOFF) flag. This allow us to put
more pressure on the TX ring buffers.
It is the ixgbe_maybe_stop_tx() call that stops the transmits, and
pktgen respecting this in the call to netif_xmit_frozen_or_drv_stopped(txq).
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
319 lines
9.8 KiB
Plaintext
319 lines
9.8 KiB
Plaintext
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HOWTO for the linux packet generator
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------------------------------------
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Date: 041221
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Enable CONFIG_NET_PKTGEN to compile and build pktgen.o either in kernel
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or as module. Module is preferred. insmod pktgen if needed. Once running
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pktgen creates a thread on each CPU where each thread has affinity to its CPU.
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Monitoring and controlling is done via /proc. Easiest to select a suitable
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a sample script and configure.
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On a dual CPU:
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ps aux | grep pkt
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root 129 0.3 0.0 0 0 ? SW 2003 523:20 [pktgen/0]
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root 130 0.3 0.0 0 0 ? SW 2003 509:50 [pktgen/1]
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For monitoring and control pktgen creates:
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/proc/net/pktgen/pgctrl
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/proc/net/pktgen/kpktgend_X
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/proc/net/pktgen/ethX
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Tuning NIC for max performance
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==============================
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The default NIC setting are (likely) not tuned for pktgen's artificial
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overload type of benchmarking, as this could hurt the normal use-case.
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Specifically increasing the TX ring buffer in the NIC:
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# ethtool -G ethX tx 1024
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A larger TX ring can improve pktgen's performance, while it can hurt
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in the general case, 1) because the TX ring buffer might get larger
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than the CPUs L1/L2 cache, 2) because it allow more queueing in the
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NIC HW layer (which is bad for bufferbloat).
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One should be careful to conclude, that packets/descriptors in the HW
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TX ring cause delay. Drivers usually delay cleaning up the
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ring-buffers (for various performance reasons), thus packets stalling
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the TX ring, might just be waiting for cleanup.
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This cleanup issues is specifically the case, for the driver ixgbe
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(Intel 82599 chip). This driver (ixgbe) combine TX+RX ring cleanups,
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and the cleanup interval is affected by the ethtool --coalesce setting
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of parameter "rx-usecs".
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For ixgbe use e.g "30" resulting in approx 33K interrupts/sec (1/30*10^6):
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# ethtool -C ethX rx-usecs 30
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Viewing threads
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===============
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/proc/net/pktgen/kpktgend_0
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Name: kpktgend_0 max_before_softirq: 10000
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Running:
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Stopped: eth1
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Result: OK: max_before_softirq=10000
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Most important the devices assigned to thread. Note! A device can only belong
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to one thread.
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Viewing devices
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===============
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Parm section holds configured info. Current hold running stats.
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Result is printed after run or after interruption. Example:
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/proc/net/pktgen/eth1
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Params: count 10000000 min_pkt_size: 60 max_pkt_size: 60
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frags: 0 delay: 0 clone_skb: 1000000 ifname: eth1
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flows: 0 flowlen: 0
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dst_min: 10.10.11.2 dst_max:
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src_min: src_max:
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src_mac: 00:00:00:00:00:00 dst_mac: 00:04:23:AC:FD:82
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udp_src_min: 9 udp_src_max: 9 udp_dst_min: 9 udp_dst_max: 9
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src_mac_count: 0 dst_mac_count: 0
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Flags:
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Current:
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pkts-sofar: 10000000 errors: 39664
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started: 1103053986245187us stopped: 1103053999346329us idle: 880401us
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seq_num: 10000011 cur_dst_mac_offset: 0 cur_src_mac_offset: 0
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cur_saddr: 0x10a0a0a cur_daddr: 0x20b0a0a
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cur_udp_dst: 9 cur_udp_src: 9
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flows: 0
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Result: OK: 13101142(c12220741+d880401) usec, 10000000 (60byte,0frags)
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763292pps 390Mb/sec (390805504bps) errors: 39664
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Configuring threads and devices
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================================
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This is done via the /proc interface easiest done via pgset in the scripts
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Examples:
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pgset "clone_skb 1" sets the number of copies of the same packet
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pgset "clone_skb 0" use single SKB for all transmits
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pgset "pkt_size 9014" sets packet size to 9014
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pgset "frags 5" packet will consist of 5 fragments
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pgset "count 200000" sets number of packets to send, set to zero
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for continuous sends until explicitly stopped.
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pgset "delay 5000" adds delay to hard_start_xmit(). nanoseconds
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pgset "dst 10.0.0.1" sets IP destination address
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(BEWARE! This generator is very aggressive!)
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pgset "dst_min 10.0.0.1" Same as dst
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pgset "dst_max 10.0.0.254" Set the maximum destination IP.
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pgset "src_min 10.0.0.1" Set the minimum (or only) source IP.
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pgset "src_max 10.0.0.254" Set the maximum source IP.
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pgset "dst6 fec0::1" IPV6 destination address
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pgset "src6 fec0::2" IPV6 source address
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pgset "dstmac 00:00:00:00:00:00" sets MAC destination address
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pgset "srcmac 00:00:00:00:00:00" sets MAC source address
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pgset "queue_map_min 0" Sets the min value of tx queue interval
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pgset "queue_map_max 7" Sets the max value of tx queue interval, for multiqueue devices
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To select queue 1 of a given device,
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use queue_map_min=1 and queue_map_max=1
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pgset "src_mac_count 1" Sets the number of MACs we'll range through.
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The 'minimum' MAC is what you set with srcmac.
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pgset "dst_mac_count 1" Sets the number of MACs we'll range through.
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The 'minimum' MAC is what you set with dstmac.
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pgset "flag [name]" Set a flag to determine behaviour. Current flags
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are: IPSRC_RND # IP source is random (between min/max)
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IPDST_RND # IP destination is random
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UDPSRC_RND, UDPDST_RND,
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MACSRC_RND, MACDST_RND
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TXSIZE_RND, IPV6,
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MPLS_RND, VID_RND, SVID_RND
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FLOW_SEQ,
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QUEUE_MAP_RND # queue map random
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QUEUE_MAP_CPU # queue map mirrors smp_processor_id()
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UDPCSUM,
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IPSEC # IPsec encapsulation (needs CONFIG_XFRM)
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NODE_ALLOC # node specific memory allocation
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pgset spi SPI_VALUE Set specific SA used to transform packet.
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pgset "udp_src_min 9" set UDP source port min, If < udp_src_max, then
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cycle through the port range.
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pgset "udp_src_max 9" set UDP source port max.
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pgset "udp_dst_min 9" set UDP destination port min, If < udp_dst_max, then
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cycle through the port range.
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pgset "udp_dst_max 9" set UDP destination port max.
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pgset "mpls 0001000a,0002000a,0000000a" set MPLS labels (in this example
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outer label=16,middle label=32,
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inner label=0 (IPv4 NULL)) Note that
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there must be no spaces between the
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arguments. Leading zeros are required.
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Do not set the bottom of stack bit,
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that's done automatically. If you do
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set the bottom of stack bit, that
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indicates that you want to randomly
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generate that address and the flag
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MPLS_RND will be turned on. You
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can have any mix of random and fixed
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labels in the label stack.
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pgset "mpls 0" turn off mpls (or any invalid argument works too!)
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pgset "vlan_id 77" set VLAN ID 0-4095
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pgset "vlan_p 3" set priority bit 0-7 (default 0)
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pgset "vlan_cfi 0" set canonical format identifier 0-1 (default 0)
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pgset "svlan_id 22" set SVLAN ID 0-4095
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pgset "svlan_p 3" set priority bit 0-7 (default 0)
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pgset "svlan_cfi 0" set canonical format identifier 0-1 (default 0)
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pgset "vlan_id 9999" > 4095 remove vlan and svlan tags
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pgset "svlan 9999" > 4095 remove svlan tag
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pgset "tos XX" set former IPv4 TOS field (e.g. "tos 28" for AF11 no ECN, default 00)
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pgset "traffic_class XX" set former IPv6 TRAFFIC CLASS (e.g. "traffic_class B8" for EF no ECN, default 00)
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pgset stop aborts injection. Also, ^C aborts generator.
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pgset "rate 300M" set rate to 300 Mb/s
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pgset "ratep 1000000" set rate to 1Mpps
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Example scripts
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===============
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A collection of small tutorial scripts for pktgen is in examples dir.
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pktgen.conf-1-1 # 1 CPU 1 dev
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pktgen.conf-1-2 # 1 CPU 2 dev
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pktgen.conf-2-1 # 2 CPU's 1 dev
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pktgen.conf-2-2 # 2 CPU's 2 dev
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pktgen.conf-1-1-rdos # 1 CPU 1 dev w. route DoS
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pktgen.conf-1-1-ip6 # 1 CPU 1 dev ipv6
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pktgen.conf-1-1-ip6-rdos # 1 CPU 1 dev ipv6 w. route DoS
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pktgen.conf-1-1-flows # 1 CPU 1 dev multiple flows.
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Run in shell: ./pktgen.conf-X-Y It does all the setup including sending.
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Interrupt affinity
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===================
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Note when adding devices to a specific CPU there good idea to also assign
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/proc/irq/XX/smp_affinity so the TX-interrupts gets bound to the same CPU.
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as this reduces cache bouncing when freeing skb's.
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Enable IPsec
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============
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Default IPsec transformation with ESP encapsulation plus Transport mode
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could be enabled by simply setting:
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pgset "flag IPSEC"
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pgset "flows 1"
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To avoid breaking existing testbed scripts for using AH type and tunnel mode,
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user could use "pgset spi SPI_VALUE" to specify which formal of transformation
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to employ.
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Current commands and configuration options
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==========================================
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** Pgcontrol commands:
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start
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stop
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** Thread commands:
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add_device
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rem_device_all
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max_before_softirq
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** Device commands:
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count
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clone_skb
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debug
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frags
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delay
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src_mac_count
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dst_mac_count
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pkt_size
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min_pkt_size
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max_pkt_size
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mpls
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udp_src_min
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udp_src_max
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udp_dst_min
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udp_dst_max
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flag
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IPSRC_RND
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IPDST_RND
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UDPSRC_RND
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UDPDST_RND
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MACSRC_RND
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MACDST_RND
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TXSIZE_RND
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IPV6
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MPLS_RND
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VID_RND
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SVID_RND
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FLOW_SEQ
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QUEUE_MAP_RND
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QUEUE_MAP_CPU
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UDPCSUM
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IPSEC
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NODE_ALLOC
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dst_min
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dst_max
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src_min
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src_max
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dst_mac
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src_mac
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clear_counters
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dst6
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src6
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flows
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flowlen
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rate
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ratep
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References:
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ftp://robur.slu.se/pub/Linux/net-development/pktgen-testing/
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ftp://robur.slu.se/pub/Linux/net-development/pktgen-testing/examples/
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Paper from Linux-Kongress in Erlangen 2004.
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ftp://robur.slu.se/pub/Linux/net-development/pktgen-testing/pktgen_paper.pdf
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Thanks to:
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Grant Grundler for testing on IA-64 and parisc, Harald Welte, Lennert Buytenhek
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Stephen Hemminger, Andi Kleen, Dave Miller and many others.
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Good luck with the linux net-development.
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