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().
  ...

1 files changed, 682 insertions, 0 deletions

diff --git a/tools/perf/Documentation/perf.data-file-format.txt b/tools/perf/Documentation/perf.data-file-format.txt
new file mode 100644
index 000000000..635ba043f
--- /dev/null
+++ b/tools/perf/Documentation/perf.data-file-format.txt
@@ -0,0 +1,682 @@
+perf.data format
+
+Uptodate as of v4.7
+
+This document describes the on-disk perf.data format, generated by perf record
+or perf inject and consumed by the other perf tools.
+
+On a high level perf.data contains the events generated by the PMUs, plus metadata.
+
+All fields are in native-endian of the machine that generated the perf.data.
+
+When perf is writing to a pipe it uses a special version of the file
+format that does not rely on seeking to adjust data offsets.  This
+format is described in "Pipe-mode data" section. The pipe data version can be
+augmented with additional events using perf inject.
+
+The file starts with a perf_header:
+
+struct perf_header {
+	char magic[8];		/* PERFILE2 */
+	uint64_t size;		/* size of the header */
+	uint64_t attr_size;	/* size of an attribute in attrs */
+	struct perf_file_section attrs;
+	struct perf_file_section data;
+	struct perf_file_section event_types;
+	uint64_t flags;
+	uint64_t flags1[3];
+};
+
+The magic number identifies the perf file and the version. Current perf versions
+use PERFILE2. Old perf versions generated a version 1 format (PERFFILE). Version 1
+is not described here. The magic number also identifies the endian. When the
+magic value is 64bit byte swapped compared the file is in non-native
+endian.
+
+A perf_file_section contains a pointer to another section of the perf file.
+The header contains three such pointers: for attributes, data and event types.
+
+struct perf_file_section {
+	uint64_t offset;	/* offset from start of file */
+	uint64_t size;		/* size of the section */
+};
+
+Flags section:
+
+For each of the optional features a perf_file_section it placed after the data
+section if the feature bit is set in the perf_header flags bitset. The
+respective perf_file_section points to the data of the additional header and
+defines its size.
+
+Some headers consist of strings, which are defined like this:
+
+struct perf_header_string {
+       uint32_t len;
+       char string[len]; /* zero terminated */
+};
+
+Some headers consist of a sequence of strings, which start with a
+
+struct perf_header_string_list {
+     uint32_t nr;
+     struct perf_header_string strings[nr]; /* variable length records */
+};
+
+The bits are the flags bits in a 256 bit bitmap starting with
+flags. These define the valid bits:
+
+	HEADER_RESERVED		= 0,	/* always cleared */
+	HEADER_FIRST_FEATURE	= 1,
+	HEADER_TRACING_DATA	= 1,
+
+Describe me.
+
+	HEADER_BUILD_ID = 2,
+
+The header consists of an sequence of build_id_event. The size of each record
+is defined by header.size (see perf_event.h). Each event defines a ELF build id
+for a executable file name for a pid. An ELF build id is a unique identifier
+assigned by the linker to an executable.
+
+struct build_id_event {
+	struct perf_event_header header;
+	pid_t			 pid;
+	uint8_t			 build_id[24];
+	char			 filename[header.size - offsetof(struct build_id_event, filename)];
+};
+
+	HEADER_HOSTNAME = 3,
+
+A perf_header_string with the hostname where the data was collected
+(uname -n)
+
+	HEADER_OSRELEASE = 4,
+
+A perf_header_string with the os release where the data was collected
+(uname -r)
+
+	HEADER_VERSION = 5,
+
+A perf_header_string with the perf user tool version where the
+data was collected. This is the same as the version of the source tree
+the perf tool was built from.
+
+	HEADER_ARCH = 6,
+
+A perf_header_string with the CPU architecture (uname -m)
+
+	HEADER_NRCPUS = 7,
+
+A structure defining the number of CPUs.
+
+struct nr_cpus {
+       uint32_t nr_cpus_available; /* CPUs not yet onlined */
+       uint32_t nr_cpus_online;
+};
+
+	HEADER_CPUDESC = 8,
+
+A perf_header_string with description of the CPU. On x86 this is the model name
+in /proc/cpuinfo
+
+	HEADER_CPUID = 9,
+
+A perf_header_string with the exact CPU type. On x86 this is
+vendor,family,model,stepping. For example: GenuineIntel,6,69,1
+
+	HEADER_TOTAL_MEM = 10,
+
+An uint64_t with the total memory in kilobytes.
+
+	HEADER_CMDLINE = 11,
+
+A perf_header_string_list with the perf arg-vector used to collect the data.
+
+	HEADER_EVENT_DESC = 12,
+
+Another description of the perf_event_attrs, more detailed than header.attrs
+including IDs and names. See perf_event.h or the man page for a description
+of a struct perf_event_attr.
+
+struct {
+       uint32_t nr; /* number of events */
+       uint32_t attr_size; /* size of each perf_event_attr */
+       struct {
+	      struct perf_event_attr attr;  /* size of attr_size */
+	      uint32_t nr_ids;
+	      struct perf_header_string event_string;
+	      uint64_t ids[nr_ids];
+       } events[nr]; /* Variable length records */
+};
+
+	HEADER_CPU_TOPOLOGY = 13,
+
+struct {
+	/*
+	 * First revision of HEADER_CPU_TOPOLOGY
+	 *
+	 * See 'struct perf_header_string_list' definition earlier
+	 * in this file.
+	 */
+
+       struct perf_header_string_list cores; /* Variable length */
+       struct perf_header_string_list threads; /* Variable length */
+
+       /*
+        * Second revision of HEADER_CPU_TOPOLOGY, older tools
+        * will not consider what comes next
+        */
+
+       struct {
+	      uint32_t core_id;
+	      uint32_t socket_id;
+       } cpus[nr]; /* Variable length records */
+       /* 'nr' comes from previously processed HEADER_NRCPUS's nr_cpu_avail */
+
+        /*
+	 * Third revision of HEADER_CPU_TOPOLOGY, older tools
+	 * will not consider what comes next
+	 */
+
+	struct perf_header_string_list dies; /* Variable length */
+	uint32_t die_id[nr_cpus_avail]; /* from previously processed HEADER_NR_CPUS, VLA */
+};
+
+Example:
+	sibling sockets : 0-8
+	sibling dies	: 0-3
+	sibling dies	: 4-7
+	sibling threads : 0-1
+	sibling threads : 2-3
+	sibling threads : 4-5
+	sibling threads : 6-7
+
+	HEADER_NUMA_TOPOLOGY = 14,
+
+	A list of NUMA node descriptions
+
+struct {
+       uint32_t nr;
+       struct {
+	      uint32_t nodenr;
+	      uint64_t mem_total;
+	      uint64_t mem_free;
+	      struct perf_header_string cpus;
+       } nodes[nr]; /* Variable length records */
+};
+
+	HEADER_BRANCH_STACK = 15,
+
+Not implemented in perf.
+
+	HEADER_PMU_MAPPINGS = 16,
+
+	A list of PMU structures, defining the different PMUs supported by perf.
+
+struct {
+       uint32_t nr;
+       struct pmu {
+	      uint32_t pmu_type;
+	      struct perf_header_string pmu_name;
+       } [nr]; /* Variable length records */
+};
+
+	HEADER_GROUP_DESC = 17,
+
+	Description of counter groups ({...} in perf syntax)
+
+struct {
+         uint32_t nr;
+         struct {
+		struct perf_header_string string;
+		uint32_t leader_idx;
+		uint32_t nr_members;
+	 } [nr]; /* Variable length records */
+};
+
+	HEADER_AUXTRACE = 18,
+
+Define additional auxtrace areas in the perf.data. auxtrace is used to store
+undecoded hardware tracing information, such as Intel Processor Trace data.
+
+/**
+ * struct auxtrace_index_entry - indexes a AUX area tracing event within a
+ *                               perf.data file.
+ * @file_offset: offset within the perf.data file
+ * @sz: size of the event
+ */
+struct auxtrace_index_entry {
+	u64			file_offset;
+	u64			sz;
+};
+
+#define PERF_AUXTRACE_INDEX_ENTRY_COUNT 256
+
+/**
+ * struct auxtrace_index - index of AUX area tracing events within a perf.data
+ *                         file.
+ * @list: linking a number of arrays of entries
+ * @nr: number of entries
+ * @entries: array of entries
+ */
+struct auxtrace_index {
+	struct list_head	list;
+	size_t			nr;
+	struct auxtrace_index_entry entries[PERF_AUXTRACE_INDEX_ENTRY_COUNT];
+};
+
+	HEADER_STAT = 19,
+
+This is merely a flag signifying that the data section contains data
+recorded from perf stat record.
+
+	HEADER_CACHE = 20,
+
+Description of the cache hierarchy. Based on the Linux sysfs format
+in /sys/devices/system/cpu/cpu*/cache/
+
+	u32 version	Currently always 1
+	u32 number_of_cache_levels
+
+struct {
+	u32	level;
+	u32	line_size;
+	u32	sets;
+	u32	ways;
+	struct perf_header_string type;
+	struct perf_header_string size;
+	struct perf_header_string map;
+}[number_of_cache_levels];
+
+	HEADER_SAMPLE_TIME = 21,
+
+Two uint64_t for the time of first sample and the time of last sample.
+
+	HEADER_SAMPLE_TOPOLOGY = 22,
+
+Physical memory map and its node assignments.
+
+The format of data in MEM_TOPOLOGY is as follows:
+
+	u64 version;            // Currently 1
+	u64 block_size_bytes;   // /sys/devices/system/memory/block_size_bytes
+	u64 count;              // number of nodes
+
+struct memory_node {
+        u64 node_id;            // node index
+        u64 size;               // size of bitmap
+        struct bitmap {
+		/* size of bitmap again */
+                u64 bitmapsize;
+		/* bitmap of memory indexes that belongs to node     */
+		/* /sys/devices/system/node/node<NODE>/memory<INDEX> */
+                u64 entries[(bitmapsize/64)+1];
+        }
+}[count];
+
+The MEM_TOPOLOGY can be displayed with following command:
+
+$ perf report --header-only -I
+...
+# memory nodes (nr 1, block size 0x8000000):
+#    0 [7G]: 0-23,32-69
+
+	HEADER_CLOCKID = 23,
+
+One uint64_t for the clockid frequency, specified, for instance, via 'perf
+record -k' (see clock_gettime()), to enable timestamps derived metrics
+conversion into wall clock time on the reporting stage.
+
+	HEADER_DIR_FORMAT = 24,
+
+The data files layout is described by HEADER_DIR_FORMAT feature.  Currently it
+holds only version number (1):
+
+  uint64_t version;
+
+The current version holds only version value (1) means that data files:
+
+- Follow the 'data.*' name format.
+
+- Contain raw events data in standard perf format as read from kernel (and need
+  to be sorted)
+
+Future versions are expected to describe different data files layout according
+to special needs.
+
+        HEADER_BPF_PROG_INFO = 25,
+
+struct perf_bpil, which contains detailed information about
+a BPF program, including type, id, tag, jited/xlated instructions, etc.
+
+        HEADER_BPF_BTF = 26,
+
+Contains BPF Type Format (BTF). For more information about BTF, please
+refer to Documentation/bpf/btf.rst.
+
+struct {
+	u32	id;
+	u32	data_size;
+	char	data[];
+};
+
+        HEADER_COMPRESSED = 27,
+
+struct {
+	u32	version;
+	u32	type;
+	u32	level;
+	u32	ratio;
+	u32	mmap_len;
+};
+
+Indicates that trace contains records of PERF_RECORD_COMPRESSED type
+that have perf_events records in compressed form.
+
+	HEADER_CPU_PMU_CAPS = 28,
+
+	A list of cpu PMU capabilities. The format of data is as below.
+
+struct {
+	u32 nr_cpu_pmu_caps;
+	{
+		char	name[];
+		char	value[];
+	} [nr_cpu_pmu_caps]
+};
+
+
+Example:
+ cpu pmu capabilities: branches=32, max_precise=3, pmu_name=icelake
+
+	HEADER_CLOCK_DATA = 29,
+
+	Contains clock id and its reference time together with wall clock
+	time taken at the 'same time', both values are in nanoseconds.
+	The format of data is as below.
+
+struct {
+	u32 version;  /* version = 1 */
+	u32 clockid;
+	u64 wall_clock_ns;
+	u64 clockid_time_ns;
+};
+
+	HEADER_HYBRID_TOPOLOGY = 30,
+
+Indicate the hybrid CPUs. The format of data is as below.
+
+struct {
+	u32 nr;
+	struct {
+		char pmu_name[];
+		char cpus[];
+	} [nr]; /* Variable length records */
+};
+
+Example:
+  hybrid cpu system:
+  cpu_core cpu list : 0-15
+  cpu_atom cpu list : 16-23
+
+	HEADER_PMU_CAPS = 31,
+
+	List of pmu capabilities (except cpu pmu which is already
+	covered by HEADER_CPU_PMU_CAPS). Note that hybrid cpu pmu
+	capabilities are also stored here.
+
+struct {
+	u32 nr_pmu;
+	struct {
+		u32 nr_caps;
+		{
+			char	name[];
+			char	value[];
+		} [nr_caps];
+		char pmu_name[];
+	} [nr_pmu];
+};
+
+	other bits are reserved and should ignored for now
+	HEADER_FEAT_BITS	= 256,
+
+Attributes
+
+This is an array of perf_event_attrs, each attr_size bytes long, which defines
+each event collected. See perf_event.h or the man page for a detailed
+description.
+
+Data
+
+This section is the bulk of the file. It consist of a stream of perf_events
+describing events. This matches the format generated by the kernel.
+See perf_event.h or the manpage for a detailed description.
+
+Some notes on parsing:
+
+Ordering
+
+The events are not necessarily in time stamp order, as they can be
+collected in parallel on different CPUs. If the events should be
+processed in time order they need to be sorted first. It is possible
+to only do a partial sort using the FINISHED_ROUND event header (see
+below). perf record guarantees that there is no reordering over a
+FINISHED_ROUND.
+
+ID vs IDENTIFIER
+
+When the event stream contains multiple events each event is identified
+by an ID. This can be either through the PERF_SAMPLE_ID or the
+PERF_SAMPLE_IDENTIFIER header. The PERF_SAMPLE_IDENTIFIER header is
+at a fixed offset from the event header, which allows reliable
+parsing of the header. Relying on ID may be ambiguous.
+IDENTIFIER is only supported by newer Linux kernels.
+
+Perf record specific events:
+
+In addition to the kernel generated event types perf record adds its
+own event types (in addition it also synthesizes some kernel events,
+for example MMAP events)
+
+	PERF_RECORD_USER_TYPE_START		= 64,
+	PERF_RECORD_HEADER_ATTR			= 64,
+
+struct attr_event {
+	struct perf_event_header header;
+	struct perf_event_attr attr;
+	uint64_t id[];
+};
+
+	PERF_RECORD_HEADER_EVENT_TYPE		= 65, /* deprecated */
+
+#define MAX_EVENT_NAME 64
+
+struct perf_trace_event_type {
+	uint64_t	event_id;
+	char	name[MAX_EVENT_NAME];
+};
+
+struct event_type_event {
+	struct perf_event_header header;
+	struct perf_trace_event_type event_type;
+};
+
+
+	PERF_RECORD_HEADER_TRACING_DATA		= 66,
+
+Describe me
+
+struct tracing_data_event {
+	struct perf_event_header header;
+	uint32_t size;
+};
+
+	PERF_RECORD_HEADER_BUILD_ID		= 67,
+
+Define a ELF build ID for a referenced executable.
+
+       struct build_id_event;   /* See above */
+
+	PERF_RECORD_FINISHED_ROUND		= 68,
+
+No event reordering over this header. No payload.
+
+	PERF_RECORD_ID_INDEX			= 69,
+
+Map event ids to CPUs and TIDs.
+
+struct id_index_entry {
+	uint64_t id;
+	uint64_t idx;
+	uint64_t cpu;
+	uint64_t tid;
+};
+
+struct id_index_event {
+	struct perf_event_header header;
+	uint64_t nr;
+	struct id_index_entry entries[nr];
+};
+
+	PERF_RECORD_AUXTRACE_INFO		= 70,
+
+Auxtrace type specific information. Describe me
+
+struct auxtrace_info_event {
+	struct perf_event_header header;
+	uint32_t type;
+	uint32_t reserved__; /* For alignment */
+	uint64_t priv[];
+};
+
+	PERF_RECORD_AUXTRACE			= 71,
+
+Defines auxtrace data. Followed by the actual data. The contents of
+the auxtrace data is dependent on the event and the CPU. For example
+for Intel Processor Trace it contains Processor Trace data generated
+by the CPU.
+
+struct auxtrace_event {
+	struct perf_event_header header;
+	uint64_t size;
+	uint64_t offset;
+	uint64_t reference;
+	uint32_t idx;
+	uint32_t tid;
+	uint32_t cpu;
+	uint32_t reserved__; /* For alignment */
+};
+
+struct aux_event {
+	struct perf_event_header header;
+	uint64_t	aux_offset;
+	uint64_t	aux_size;
+	uint64_t	flags;
+};
+
+	PERF_RECORD_AUXTRACE_ERROR		= 72,
+
+Describes an error in hardware tracing
+
+enum auxtrace_error_type {
+	PERF_AUXTRACE_ERROR_ITRACE  = 1,
+	PERF_AUXTRACE_ERROR_MAX
+};
+
+#define MAX_AUXTRACE_ERROR_MSG 64
+
+struct auxtrace_error_event {
+	struct perf_event_header header;
+	uint32_t type;
+	uint32_t code;
+	uint32_t cpu;
+	uint32_t pid;
+	uint32_t tid;
+	uint32_t reserved__; /* For alignment */
+	uint64_t ip;
+	char msg[MAX_AUXTRACE_ERROR_MSG];
+};
+
+	PERF_RECORD_HEADER_FEATURE		= 80,
+
+Describes a header feature. These are records used in pipe-mode that
+contain information that otherwise would be in perf.data file's header.
+
+	PERF_RECORD_COMPRESSED 			= 81,
+
+struct compressed_event {
+	struct perf_event_header	header;
+	char				data[];
+};
+
+	PERF_RECORD_FINISHED_INIT			= 82,
+
+Marks the end of records for the system, pre-existing threads in system wide
+sessions, etc. Those are the ones prefixed PERF_RECORD_USER_*.
+
+This is used, for instance, to 'perf inject' events after init and before
+regular events, those emitted by the kernel, to support combining guest and
+host records.
+
+
+The header is followed by compressed data frame that can be decompressed
+into array of perf trace records. The size of the entire compressed event
+record including the header is limited by the max value of header.size.
+
+Event types
+
+Define the event attributes with their IDs.
+
+An array bound by the perf_file_section size.
+
+	struct {
+		struct perf_event_attr attr;   /* Size defined by header.attr_size */
+		struct perf_file_section ids;
+	}
+
+ids points to a array of uint64_t defining the ids for event attr attr.
+
+Pipe-mode data
+
+Pipe-mode avoid seeks in the file by removing the perf_file_section and flags
+from the struct perf_header. The trimmed header is:
+
+struct perf_pipe_file_header {
+	u64				magic;
+	u64				size;
+};
+
+The information about attrs, data, and event_types is instead in the
+synthesized events PERF_RECORD_ATTR, PERF_RECORD_HEADER_TRACING_DATA,
+PERF_RECORD_HEADER_EVENT_TYPE, and PERF_RECORD_HEADER_FEATURE
+that are generated by perf record in pipe-mode.
+
+
+References:
+
+include/uapi/linux/perf_event.h
+
+This is the canonical description of the kernel generated perf_events
+and the perf_event_attrs.
+
+perf_events manpage
+
+A manpage describing perf_event and perf_event_attr is here:
+http://web.eece.maine.edu/~vweaver/projects/perf_events/programming.html
+This tends to be slightly behind the kernel include, but has better
+descriptions.  An (typically older) version of the man page may be
+included with the standard Linux man pages, available with "man
+perf_events"
+
+pmu-tools
+
+https://github.com/andikleen/pmu-tools/tree/master/parser
+
+A definition of the perf.data format in python "construct" format is available
+in pmu-tools parser. This allows to read perf.data from python and dump it.
+
+quipper
+
+The quipper C++ parser is available at
+http://github.com/google/perf_data_converter/tree/master/src/quipper
+