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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
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Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
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+perf-list(1)
+============
+
+NAME
+----
+perf-list - List all symbolic event types
+
+SYNOPSIS
+--------
+[verse]
+'perf list' [--no-desc] [--long-desc]
+ [hw|sw|cache|tracepoint|pmu|sdt|metric|metricgroup|event_glob]
+
+DESCRIPTION
+-----------
+This command displays the symbolic event types which can be selected in the
+various perf commands with the -e option.
+
+OPTIONS
+-------
+-d::
+--desc::
+Print extra event descriptions. (default)
+
+--no-desc::
+Don't print descriptions.
+
+-v::
+--long-desc::
+Print longer event descriptions.
+
+--debug::
+Enable debugging output.
+
+--details::
+Print how named events are resolved internally into perf events, and also
+any extra expressions computed by perf stat.
+
+--deprecated::
+Print deprecated events. By default the deprecated events are hidden.
+
+--cputype::
+Print events applying cpu with this type for hybrid platform
+(e.g. --cputype core or --cputype atom)
+
+[[EVENT_MODIFIERS]]
+EVENT MODIFIERS
+---------------
+
+Events can optionally have a modifier by appending a colon and one or
+more modifiers. Modifiers allow the user to restrict the events to be
+counted. The following modifiers exist:
+
+ u - user-space counting
+ k - kernel counting
+ h - hypervisor counting
+ I - non idle counting
+ G - guest counting (in KVM guests)
+ H - host counting (not in KVM guests)
+ p - precise level
+ P - use maximum detected precise level
+ S - read sample value (PERF_SAMPLE_READ)
+ D - pin the event to the PMU
+ W - group is weak and will fallback to non-group if not schedulable,
+ e - group or event are exclusive and do not share the PMU
+
+The 'p' modifier can be used for specifying how precise the instruction
+address should be. The 'p' modifier can be specified multiple times:
+
+ 0 - SAMPLE_IP can have arbitrary skid
+ 1 - SAMPLE_IP must have constant skid
+ 2 - SAMPLE_IP requested to have 0 skid
+ 3 - SAMPLE_IP must have 0 skid, or uses randomization to avoid
+ sample shadowing effects.
+
+For Intel systems precise event sampling is implemented with PEBS
+which supports up to precise-level 2, and precise level 3 for
+some special cases
+
+On AMD systems it is implemented using IBS (up to precise-level 2).
+The precise modifier works with event types 0x76 (cpu-cycles, CPU
+clocks not halted) and 0xC1 (micro-ops retired). Both events map to
+IBS execution sampling (IBS op) with the IBS Op Counter Control bit
+(IbsOpCntCtl) set respectively (see the
+Core Complex (CCX) -> Processor x86 Core -> Instruction Based Sampling (IBS)
+section of the [AMD Processor Programming Reference (PPR)] relevant to the
+family, model and stepping of the processor being used).
+
+Manual Volume 2: System Programming, 13.3 Instruction-Based
+Sampling). Examples to use IBS:
+
+ perf record -a -e cpu-cycles:p ... # use ibs op counting cycles
+ perf record -a -e r076:p ... # same as -e cpu-cycles:p
+ perf record -a -e r0C1:p ... # use ibs op counting micro-ops
+
+RAW HARDWARE EVENT DESCRIPTOR
+-----------------------------
+Even when an event is not available in a symbolic form within perf right now,
+it can be encoded in a per processor specific way.
+
+For instance on x86 CPUs, N is a hexadecimal value that represents the raw register encoding with the
+layout of IA32_PERFEVTSELx MSRs (see [IntelĀ® 64 and IA-32 Architectures Software Developer's Manual Volume 3B: System Programming Guide] Figure 30-1 Layout
+of IA32_PERFEVTSELx MSRs) or AMD's PERF_CTL MSRs (see the
+Core Complex (CCX) -> Processor x86 Core -> MSR Registers section of the
+[AMD Processor Programming Reference (PPR)] relevant to the family, model
+and stepping of the processor being used).
+
+Note: Only the following bit fields can be set in x86 counter
+registers: event, umask, edge, inv, cmask. Esp. guest/host only and
+OS/user mode flags must be setup using <<EVENT_MODIFIERS, EVENT
+MODIFIERS>>.
+
+Example:
+
+If the Intel docs for a QM720 Core i7 describe an event as:
+
+ Event Umask Event Mask
+ Num. Value Mnemonic Description Comment
+
+ A8H 01H LSD.UOPS Counts the number of micro-ops Use cmask=1 and
+ delivered by loop stream detector invert to count
+ cycles
+
+raw encoding of 0x1A8 can be used:
+
+ perf stat -e r1a8 -a sleep 1
+ perf record -e r1a8 ...
+
+It's also possible to use pmu syntax:
+
+ perf record -e r1a8 -a sleep 1
+ perf record -e cpu/r1a8/ ...
+ perf record -e cpu/r0x1a8/ ...
+
+Some processors, like those from AMD, support event codes and unit masks
+larger than a byte. In such cases, the bits corresponding to the event
+configuration parameters can be seen with:
+
+ cat /sys/bus/event_source/devices/<pmu>/format/<config>
+
+Example:
+
+If the AMD docs for an EPYC 7713 processor describe an event as:
+
+ Event Umask Event Mask
+ Num. Value Mnemonic Description
+
+ 28FH 03H op_cache_hit_miss.op_cache_hit Counts Op Cache micro-tag
+ hit events.
+
+raw encoding of 0x0328F cannot be used since the upper nibble of the
+EventSelect bits have to be specified via bits 32-35 as can be seen with:
+
+ cat /sys/bus/event_source/devices/cpu/format/event
+
+raw encoding of 0x20000038F should be used instead:
+
+ perf stat -e r20000038f -a sleep 1
+ perf record -e r20000038f ...
+
+It's also possible to use pmu syntax:
+
+ perf record -e r20000038f -a sleep 1
+ perf record -e cpu/r20000038f/ ...
+ perf record -e cpu/r0x20000038f/ ...
+
+You should refer to the processor specific documentation for getting these
+details. Some of them are referenced in the SEE ALSO section below.
+
+ARBITRARY PMUS
+--------------
+
+perf also supports an extended syntax for specifying raw parameters
+to PMUs. Using this typically requires looking up the specific event
+in the CPU vendor specific documentation.
+
+The available PMUs and their raw parameters can be listed with
+
+ ls /sys/devices/*/format
+
+For example the raw event "LSD.UOPS" core pmu event above could
+be specified as
+
+ perf stat -e cpu/event=0xa8,umask=0x1,name=LSD.UOPS_CYCLES,cmask=0x1/ ...
+
+ or using extended name syntax
+
+ perf stat -e cpu/event=0xa8,umask=0x1,cmask=0x1,name=\'LSD.UOPS_CYCLES:cmask=0x1\'/ ...
+
+PER SOCKET PMUS
+---------------
+
+Some PMUs are not associated with a core, but with a whole CPU socket.
+Events on these PMUs generally cannot be sampled, but only counted globally
+with perf stat -a. They can be bound to one logical CPU, but will measure
+all the CPUs in the same socket.
+
+This example measures memory bandwidth every second
+on the first memory controller on socket 0 of a Intel Xeon system
+
+ perf stat -C 0 -a uncore_imc_0/cas_count_read/,uncore_imc_0/cas_count_write/ -I 1000 ...
+
+Each memory controller has its own PMU. Measuring the complete system
+bandwidth would require specifying all imc PMUs (see perf list output),
+and adding the values together. To simplify creation of multiple events,
+prefix and glob matching is supported in the PMU name, and the prefix
+'uncore_' is also ignored when performing the match. So the command above
+can be expanded to all memory controllers by using the syntaxes:
+
+ perf stat -C 0 -a imc/cas_count_read/,imc/cas_count_write/ -I 1000 ...
+ perf stat -C 0 -a *imc*/cas_count_read/,*imc*/cas_count_write/ -I 1000 ...
+
+This example measures the combined core power every second
+
+ perf stat -I 1000 -e power/energy-cores/ -a
+
+ACCESS RESTRICTIONS
+-------------------
+
+For non root users generally only context switched PMU events are available.
+This is normally only the events in the cpu PMU, the predefined events
+like cycles and instructions and some software events.
+
+Other PMUs and global measurements are normally root only.
+Some event qualifiers, such as "any", are also root only.
+
+This can be overridden by setting the kernel.perf_event_paranoid
+sysctl to -1, which allows non root to use these events.
+
+For accessing trace point events perf needs to have read access to
+/sys/kernel/debug/tracing, even when perf_event_paranoid is in a relaxed
+setting.
+
+TRACING
+-------
+
+Some PMUs control advanced hardware tracing capabilities, such as Intel PT,
+that allows low overhead execution tracing. These are described in a separate
+intel-pt.txt document.
+
+PARAMETERIZED EVENTS
+--------------------
+
+Some pmu events listed by 'perf-list' will be displayed with '?' in them. For
+example:
+
+ hv_gpci/dtbp_ptitc,phys_processor_idx=?/
+
+This means that when provided as an event, a value for '?' must
+also be supplied. For example:
+
+ perf stat -C 0 -e 'hv_gpci/dtbp_ptitc,phys_processor_idx=0x2/' ...
+
+EVENT QUALIFIERS:
+
+It is also possible to add extra qualifiers to an event:
+
+percore:
+
+Sums up the event counts for all hardware threads in a core, e.g.:
+
+
+ perf stat -e cpu/event=0,umask=0x3,percore=1/
+
+
+EVENT GROUPS
+------------
+
+Perf supports time based multiplexing of events, when the number of events
+active exceeds the number of hardware performance counters. Multiplexing
+can cause measurement errors when the workload changes its execution
+profile.
+
+When metrics are computed using formulas from event counts, it is useful to
+ensure some events are always measured together as a group to minimize multiplexing
+errors. Event groups can be specified using { }.
+
+ perf stat -e '{instructions,cycles}' ...
+
+The number of available performance counters depend on the CPU. A group
+cannot contain more events than available counters.
+For example Intel Core CPUs typically have four generic performance counters
+for the core, plus three fixed counters for instructions, cycles and
+ref-cycles. Some special events have restrictions on which counter they
+can schedule, and may not support multiple instances in a single group.
+When too many events are specified in the group some of them will not
+be measured.
+
+Globally pinned events can limit the number of counters available for
+other groups. On x86 systems, the NMI watchdog pins a counter by default.
+The nmi watchdog can be disabled as root with
+
+ echo 0 > /proc/sys/kernel/nmi_watchdog
+
+Events from multiple different PMUs cannot be mixed in a group, with
+some exceptions for software events.
+
+LEADER SAMPLING
+---------------
+
+perf also supports group leader sampling using the :S specifier.
+
+ perf record -e '{cycles,instructions}:S' ...
+ perf report --group
+
+Normally all events in an event group sample, but with :S only
+the first event (the leader) samples, and it only reads the values of the
+other events in the group.
+
+However, in the case AUX area events (e.g. Intel PT or CoreSight), the AUX
+area event must be the leader, so then the second event samples, not the first.
+
+OPTIONS
+-------
+
+Without options all known events will be listed.
+
+To limit the list use:
+
+. 'hw' or 'hardware' to list hardware events such as cache-misses, etc.
+
+. 'sw' or 'software' to list software events such as context switches, etc.
+
+. 'cache' or 'hwcache' to list hardware cache events such as L1-dcache-loads, etc.
+
+. 'tracepoint' to list all tracepoint events, alternatively use
+ 'subsys_glob:event_glob' to filter by tracepoint subsystems such as sched,
+ block, etc.
+
+. 'pmu' to print the kernel supplied PMU events.
+
+. 'sdt' to list all Statically Defined Tracepoint events.
+
+. 'metric' to list metrics
+
+. 'metricgroup' to list metricgroups with metrics.
+
+. If none of the above is matched, it will apply the supplied glob to all
+ events, printing the ones that match.
+
+. As a last resort, it will do a substring search in all event names.
+
+One or more types can be used at the same time, listing the events for the
+types specified.
+
+Support raw format:
+
+. '--raw-dump', shows the raw-dump of all the events.
+. '--raw-dump [hw|sw|cache|tracepoint|pmu|event_glob]', shows the raw-dump of
+ a certain kind of events.
+
+SEE ALSO
+--------
+linkperf:perf-stat[1], linkperf:perf-top[1],
+linkperf:perf-record[1],
+http://www.intel.com/sdm/[IntelĀ® 64 and IA-32 Architectures Software Developer's Manual Volume 3B: System Programming Guide],
+https://bugzilla.kernel.org/show_bug.cgi?id=206537[AMD Processor Programming Reference (PPR)]