aboutsummaryrefslogtreecommitdiff
path: root/Documentation/networking/statistics.rst
diff options
context:
space:
mode:
authorLibravatar Linus Torvalds <torvalds@linux-foundation.org>2023-02-21 18:24:12 -0800
committerLibravatar Linus Torvalds <torvalds@linux-foundation.org>2023-02-21 18:24:12 -0800
commit5b7c4cabbb65f5c469464da6c5f614cbd7f730f2 (patch)
treecc5c2d0a898769fd59549594fedb3ee6f84e59a0 /Documentation/networking/statistics.rst
downloadlinux-5b7c4cabbb65f5c469464da6c5f614cbd7f730f2.tar.gz
linux-5b7c4cabbb65f5c469464da6c5f614cbd7f730f2.zip
Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-nextgrafted
Pull networking updates from Jakub Kicinski: "Core: - Add dedicated kmem_cache for typical/small skb->head, avoid having to access struct page at kfree time, and improve memory use. - Introduce sysctl to set default RPS configuration for new netdevs. - Define Netlink protocol specification format which can be used to describe messages used by each family and auto-generate parsers. Add tools for generating kernel data structures and uAPI headers. - Expose all net/core sysctls inside netns. - Remove 4s sleep in netpoll if carrier is instantly detected on boot. - Add configurable limit of MDB entries per port, and port-vlan. - Continue populating drop reasons throughout the stack. - Retire a handful of legacy Qdiscs and classifiers. Protocols: - Support IPv4 big TCP (TSO frames larger than 64kB). - Add IP_LOCAL_PORT_RANGE socket option, to control local port range on socket by socket basis. - Track and report in procfs number of MPTCP sockets used. - Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path manager. - IPv6: don't check net.ipv6.route.max_size and rely on garbage collection to free memory (similarly to IPv4). - Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986). - ICMP: add per-rate limit counters. - Add support for user scanning requests in ieee802154. - Remove static WEP support. - Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate reporting. - WiFi 7 EHT channel puncturing support (client & AP). BPF: - Add a rbtree data structure following the "next-gen data structure" precedent set by recently added linked list, that is, by using kfunc + kptr instead of adding a new BPF map type. - Expose XDP hints via kfuncs with initial support for RX hash and timestamp metadata. - Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to better support decap on GRE tunnel devices not operating in collect metadata. - Improve x86 JIT's codegen for PROBE_MEM runtime error checks. - Remove the need for trace_printk_lock for bpf_trace_printk and bpf_trace_vprintk helpers. - Extend libbpf's bpf_tracing.h support for tracing arguments of kprobes/uprobes and syscall as a special case. - Significantly reduce the search time for module symbols by livepatch and BPF. - Enable cpumasks to be used as kptrs, which is useful for tracing programs tracking which tasks end up running on which CPUs in different time intervals. - Add support for BPF trampoline on s390x and riscv64. - Add capability to export the XDP features supported by the NIC. - Add __bpf_kfunc tag for marking kernel functions as kfuncs. - Add cgroup.memory=nobpf kernel parameter option to disable BPF memory accounting for container environments. Netfilter: - Remove the CLUSTERIP target. It has been marked as obsolete for years, and we still have WARN splats wrt races of the out-of-band /proc interface installed by this target. - Add 'destroy' commands to nf_tables. They are identical to the existing 'delete' commands, but do not return an error if the referenced object (set, chain, rule...) did not exist. Driver API: - Improve cpumask_local_spread() locality to help NICs set the right IRQ affinity on AMD platforms. - Separate C22 and C45 MDIO bus transactions more clearly. - Introduce new DCB table to control DSCP rewrite on egress. - Support configuration of Physical Layer Collision Avoidance (PLCA) Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of shared medium Ethernet. - Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing preemption of low priority frames by high priority frames. - Add support for controlling MACSec offload using netlink SET. - Rework devlink instance refcounts to allow registration and de-registration under the instance lock. Split the code into multiple files, drop some of the unnecessarily granular locks and factor out common parts of netlink operation handling. - Add TX frame aggregation parameters (for USB drivers). - Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning messages with notifications for debug. - Allow offloading of UDP NEW connections via act_ct. - Add support for per action HW stats in TC. - Support hardware miss to TC action (continue processing in SW from a specific point in the action chain). - Warn if old Wireless Extension user space interface is used with modern cfg80211/mac80211 drivers. Do not support Wireless Extensions for Wi-Fi 7 devices at all. Everyone should switch to using nl80211 interface instead. - Improve the CAN bit timing configuration. Use extack to return error messages directly to user space, update the SJW handling, including the definition of a new default value that will benefit CAN-FD controllers, by increasing their oscillator tolerance. New hardware / drivers: - Ethernet: - nVidia BlueField-3 support (control traffic driver) - Ethernet support for imx93 SoCs - Motorcomm yt8531 gigabit Ethernet PHY - onsemi NCN26000 10BASE-T1S PHY (with support for PLCA) - Microchip LAN8841 PHY (incl. cable diagnostics and PTP) - Amlogic gxl MDIO mux - WiFi: - RealTek RTL8188EU (rtl8xxxu) - Qualcomm Wi-Fi 7 devices (ath12k) - CAN: - Renesas R-Car V4H Drivers: - Bluetooth: - Set Per Platform Antenna Gain (PPAG) for Intel controllers. - Ethernet NICs: - Intel (1G, igc): - support TSN / Qbv / packet scheduling features of i226 model - Intel (100G, ice): - use GNSS subsystem instead of TTY - multi-buffer XDP support - extend support for GPIO pins to E823 devices - nVidia/Mellanox: - update the shared buffer configuration on PFC commands - implement PTP adjphase function for HW offset control - TC support for Geneve and GRE with VF tunnel offload - more efficient crypto key management method - multi-port eswitch support - Netronome/Corigine: - add DCB IEEE support - support IPsec offloading for NFP3800 - Freescale/NXP (enetc): - support XDP_REDIRECT for XDP non-linear buffers - improve reconfig, avoid link flap and waiting for idle - support MAC Merge layer - Other NICs: - sfc/ef100: add basic devlink support for ef100 - ionic: rx_push mode operation (writing descriptors via MMIO) - bnxt: use the auxiliary bus abstraction for RDMA - r8169: disable ASPM and reset bus in case of tx timeout - cpsw: support QSGMII mode for J721e CPSW9G - cpts: support pulse-per-second output - ngbe: add an mdio bus driver - usbnet: optimize usbnet_bh() by avoiding unnecessary queuing - r8152: handle devices with FW with NCM support - amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation - virtio-net: support multi buffer XDP - virtio/vsock: replace virtio_vsock_pkt with sk_buff - tsnep: XDP support - Ethernet high-speed switches: - nVidia/Mellanox (mlxsw): - add support for latency TLV (in FW control messages) - Microchip (sparx5): - separate explicit and implicit traffic forwarding rules, make the implicit rules always active - add support for egress DSCP rewrite - IS0 VCAP support (Ingress Classification) - IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS etc.) - ES2 VCAP support (Egress Access Control) - support for Per-Stream Filtering and Policing (802.1Q, 8.6.5.1) - Ethernet embedded switches: - Marvell (mv88e6xxx): - add MAB (port auth) offload support - enable PTP receive for mv88e6390 - NXP (ocelot): - support MAC Merge layer - support for the the vsc7512 internal copper phys - Microchip: - lan9303: convert to PHYLINK - lan966x: support TC flower filter statistics - lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x - lan937x: support Credit Based Shaper configuration - ksz9477: support Energy Efficient Ethernet - other: - qca8k: convert to regmap read/write API, use bulk operations - rswitch: Improve TX timestamp accuracy - Intel WiFi (iwlwifi): - EHT (Wi-Fi 7) rate reporting - STEP equalizer support: transfer some STEP (connection to radio on platforms with integrated wifi) related parameters from the BIOS to the firmware. - Qualcomm 802.11ax WiFi (ath11k): - IPQ5018 support - Fine Timing Measurement (FTM) responder role support - channel 177 support - MediaTek WiFi (mt76): - per-PHY LED support - mt7996: EHT (Wi-Fi 7) support - Wireless Ethernet Dispatch (WED) reset support - switch to using page pool allocator - RealTek WiFi (rtw89): - support new version of Bluetooth co-existance - Mobile: - rmnet: support TX aggregation" * tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits) page_pool: add a comment explaining the fragment counter usage net: ethtool: fix __ethtool_dev_mm_supported() implementation ethtool: pse-pd: Fix double word in comments xsk: add linux/vmalloc.h to xsk.c sefltests: netdevsim: wait for devlink instance after netns removal selftest: fib_tests: Always cleanup before exit net/mlx5e: Align IPsec ASO result memory to be as required by hardware net/mlx5e: TC, Set CT miss to the specific ct action instance net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG net/mlx5: Refactor tc miss handling to a single function net/mlx5: Kconfig: Make tc offload depend on tc skb extension net/sched: flower: Support hardware miss to tc action net/sched: flower: Move filter handle initialization earlier net/sched: cls_api: Support hardware miss to tc action net/sched: Rename user cookie and act cookie sfc: fix builds without CONFIG_RTC_LIB sfc: clean up some inconsistent indentings net/mlx4_en: Introduce flexible array to silence overflow warning net: lan966x: Fix possible deadlock inside PTP net/ulp: Remove redundant ->clone() test in inet_clone_ulp(). ...
Diffstat (limited to 'Documentation/networking/statistics.rst')
-rw-r--r--Documentation/networking/statistics.rst221
1 files changed, 221 insertions, 0 deletions
diff --git a/Documentation/networking/statistics.rst b/Documentation/networking/statistics.rst
new file mode 100644
index 000000000..551b3cc29
--- /dev/null
+++ b/Documentation/networking/statistics.rst
@@ -0,0 +1,221 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+====================
+Interface statistics
+====================
+
+Overview
+========
+
+This document is a guide to Linux network interface statistics.
+
+There are three main sources of interface statistics in Linux:
+
+ - standard interface statistics based on
+ :c:type:`struct rtnl_link_stats64 <rtnl_link_stats64>`;
+ - protocol-specific statistics; and
+ - driver-defined statistics available via ethtool.
+
+Standard interface statistics
+-----------------------------
+
+There are multiple interfaces to reach the standard statistics.
+Most commonly used is the `ip` command from `iproute2`::
+
+ $ ip -s -s link show dev ens4u1u1
+ 6: ens4u1u1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP mode DEFAULT group default qlen 1000
+ link/ether 48:2a:e3:4c:b1:d1 brd ff:ff:ff:ff:ff:ff
+ RX: bytes packets errors dropped overrun mcast
+ 74327665117 69016965 0 0 0 0
+ RX errors: length crc frame fifo missed
+ 0 0 0 0 0
+ TX: bytes packets errors dropped carrier collsns
+ 21405556176 44608960 0 0 0 0
+ TX errors: aborted fifo window heartbeat transns
+ 0 0 0 0 128
+ altname enp58s0u1u1
+
+Note that `-s` has been specified twice to see all members of
+:c:type:`struct rtnl_link_stats64 <rtnl_link_stats64>`.
+If `-s` is specified once the detailed errors won't be shown.
+
+`ip` supports JSON formatting via the `-j` option.
+
+Protocol-specific statistics
+----------------------------
+
+Protocol-specific statistics are exposed via relevant interfaces,
+the same interfaces as are used to configure them.
+
+ethtool
+~~~~~~~
+
+Ethtool exposes common low-level statistics.
+All the standard statistics are expected to be maintained
+by the device, not the driver (as opposed to driver-defined stats
+described in the next section which mix software and hardware stats).
+For devices which contain unmanaged
+switches (e.g. legacy SR-IOV or multi-host NICs) the events counted
+may not pertain exclusively to the packets destined to
+the local host interface. In other words the events may
+be counted at the network port (MAC/PHY blocks) without separation
+for different host side (PCIe) devices. Such ambiguity must not
+be present when internal switch is managed by Linux (so called
+switchdev mode for NICs).
+
+Standard ethtool statistics can be accessed via the interfaces used
+for configuration. For example ethtool interface used
+to configure pause frames can report corresponding hardware counters::
+
+ $ ethtool --include-statistics -a eth0
+ Pause parameters for eth0:
+ Autonegotiate: on
+ RX: on
+ TX: on
+ Statistics:
+ tx_pause_frames: 1
+ rx_pause_frames: 1
+
+General Ethernet statistics not associated with any particular
+functionality are exposed via ``ethtool -S $ifc`` by specifying
+the ``--groups`` parameter::
+
+ $ ethtool -S eth0 --groups eth-phy eth-mac eth-ctrl rmon
+ Stats for eth0:
+ eth-phy-SymbolErrorDuringCarrier: 0
+ eth-mac-FramesTransmittedOK: 1
+ eth-mac-FrameTooLongErrors: 1
+ eth-ctrl-MACControlFramesTransmitted: 1
+ eth-ctrl-MACControlFramesReceived: 0
+ eth-ctrl-UnsupportedOpcodesReceived: 1
+ rmon-etherStatsUndersizePkts: 1
+ rmon-etherStatsJabbers: 0
+ rmon-rx-etherStatsPkts64Octets: 1
+ rmon-rx-etherStatsPkts65to127Octets: 0
+ rmon-rx-etherStatsPkts128to255Octets: 0
+ rmon-tx-etherStatsPkts64Octets: 2
+ rmon-tx-etherStatsPkts65to127Octets: 3
+ rmon-tx-etherStatsPkts128to255Octets: 0
+
+Driver-defined statistics
+-------------------------
+
+Driver-defined ethtool statistics can be dumped using `ethtool -S $ifc`, e.g.::
+
+ $ ethtool -S ens4u1u1
+ NIC statistics:
+ tx_single_collisions: 0
+ tx_multi_collisions: 0
+
+uAPIs
+=====
+
+procfs
+------
+
+The historical `/proc/net/dev` text interface gives access to the list
+of interfaces as well as their statistics.
+
+Note that even though this interface is using
+:c:type:`struct rtnl_link_stats64 <rtnl_link_stats64>`
+internally it combines some of the fields.
+
+sysfs
+-----
+
+Each device directory in sysfs contains a `statistics` directory (e.g.
+`/sys/class/net/lo/statistics/`) with files corresponding to
+members of :c:type:`struct rtnl_link_stats64 <rtnl_link_stats64>`.
+
+This simple interface is convenient especially in constrained/embedded
+environments without access to tools. However, it's inefficient when
+reading multiple stats as it internally performs a full dump of
+:c:type:`struct rtnl_link_stats64 <rtnl_link_stats64>`
+and reports only the stat corresponding to the accessed file.
+
+Sysfs files are documented in
+`Documentation/ABI/testing/sysfs-class-net-statistics`.
+
+
+netlink
+-------
+
+`rtnetlink` (`NETLINK_ROUTE`) is the preferred method of accessing
+:c:type:`struct rtnl_link_stats64 <rtnl_link_stats64>` stats.
+
+Statistics are reported both in the responses to link information
+requests (`RTM_GETLINK`) and statistic requests (`RTM_GETSTATS`,
+when `IFLA_STATS_LINK_64` bit is set in the `.filter_mask` of the request).
+
+ethtool
+-------
+
+Ethtool IOCTL interface allows drivers to report implementation
+specific statistics. Historically it has also been used to report
+statistics for which other APIs did not exist, like per-device-queue
+statistics, or standard-based statistics (e.g. RFC 2863).
+
+Statistics and their string identifiers are retrieved separately.
+Identifiers via `ETHTOOL_GSTRINGS` with `string_set` set to `ETH_SS_STATS`,
+and values via `ETHTOOL_GSTATS`. User space should use `ETHTOOL_GDRVINFO`
+to retrieve the number of statistics (`.n_stats`).
+
+ethtool-netlink
+---------------
+
+Ethtool netlink is a replacement for the older IOCTL interface.
+
+Protocol-related statistics can be requested in get commands by setting
+the `ETHTOOL_FLAG_STATS` flag in `ETHTOOL_A_HEADER_FLAGS`. Currently
+statistics are supported in the following commands:
+
+ - `ETHTOOL_MSG_PAUSE_GET`
+ - `ETHTOOL_MSG_FEC_GET`
+ - `ETHTOOL_MSG_MM_GET`
+
+debugfs
+-------
+
+Some drivers expose extra statistics via `debugfs`.
+
+struct rtnl_link_stats64
+========================
+
+.. kernel-doc:: include/uapi/linux/if_link.h
+ :identifiers: rtnl_link_stats64
+
+Notes for driver authors
+========================
+
+Drivers should report all statistics which have a matching member in
+:c:type:`struct rtnl_link_stats64 <rtnl_link_stats64>` exclusively
+via `.ndo_get_stats64`. Reporting such standard stats via ethtool
+or debugfs will not be accepted.
+
+Drivers must ensure best possible compliance with
+:c:type:`struct rtnl_link_stats64 <rtnl_link_stats64>`.
+Please note for example that detailed error statistics must be
+added into the general `rx_error` / `tx_error` counters.
+
+The `.ndo_get_stats64` callback can not sleep because of accesses
+via `/proc/net/dev`. If driver may sleep when retrieving the statistics
+from the device it should do so periodically asynchronously and only return
+a recent copy from `.ndo_get_stats64`. Ethtool interrupt coalescing interface
+allows setting the frequency of refreshing statistics, if needed.
+
+Retrieving ethtool statistics is a multi-syscall process, drivers are advised
+to keep the number of statistics constant to avoid race conditions with
+user space trying to read them.
+
+Statistics must persist across routine operations like bringing the interface
+down and up.
+
+Kernel-internal data structures
+-------------------------------
+
+The following structures are internal to the kernel, their members are
+translated to netlink attributes when dumped. Drivers must not overwrite
+the statistics they don't report with 0.
+
+- ethtool_pause_stats()
+- ethtool_fec_stats()