ARK-OS/arkos/kernel/tools/perf/Documentation/perf-report.txt

perf-report(1)
==============

NAME
----
perf-report - Read perf.data (created by perf record) and display the profile

SYNOPSIS
--------
[verse]
'perf report' [-i <file> | --input=file]

DESCRIPTION
-----------
This command displays the performance counter profile information recorded
via perf record.

OPTIONS
-------
-i::
--input=::
        Input file name. (default: perf.data unless stdin is a fifo)

-v::
--verbose::
        Be more verbose. (show symbol address, etc)

-q::
--quiet::
	Do not show any warnings or messages.  (Suppress -v)

-n::
--show-nr-samples::
	Show the number of samples for each symbol

--show-cpu-utilization::
        Show sample percentage for different cpu modes.

-T::
--threads::
	Show per-thread event counters.  The input data file should be recorded
	with -s option.
-c::
--comms=::
	Only consider symbols in these comms. CSV that understands
	file://filename entries.  This option will affect the percentage of
	the overhead and latency columns.  See --percentage for more info.
--pid=::
        Only show events for given process ID (comma separated list).

--tid=::
        Only show events for given thread ID (comma separated list).
-d::
--dsos=::
	Only consider symbols in these dsos. CSV that understands
	file://filename entries.  This option will affect the percentage of
	the overhead and latency columns.  See --percentage for more info.
-S::
--symbols=::
	Only consider these symbols. CSV that understands
	file://filename entries.  This option will affect the percentage of
	the overhead and latency columns.  See --percentage for more info.

--symbol-filter=::
	Only show symbols that match (partially) with this filter.

-U::
--hide-unresolved::
        Only display entries resolved to a symbol.

--parallelism::
        Only consider these parallelism levels. Parallelism level is the number
        of threads that actively run on CPUs at the time of sample. The flag
        accepts single number, comma-separated list, and ranges (for example:
        "1", "7,8", "1,64-128"). This is useful in understanding what a program
        is doing during sequential/low-parallelism phases as compared to
        high-parallelism phases. This option will affect the percentage of
        the overhead and latency columns. See --percentage for more info.
        Also see the `CPU and latency overheads' section for more details.

--latency::
        Show latency-centric profile rather than the default
        CPU-consumption-centric profile
        (requires perf record --latency flag).

-s::
--sort=::
	Sort histogram entries by given key(s) - multiple keys can be specified
	in CSV format.  Following sort keys are available:
	pid, comm, dso, symbol, parent, cpu, socket, srcline, weight,
	local_weight, cgroup_id, addr.

	Each key has following meaning:

	- comm: command (name) of the task which can be read via /proc/<pid>/comm
	- pid: command and tid of the task
	- tgid: command and tgid of the task
	- dso: name of library or module executed at the time of sample
	- dso_size: size of library or module executed at the time of sample
	- symbol: name of function executed at the time of sample
	- symbol_size: size of function executed at the time of sample
	- parent: name of function matched to the parent regex filter. Unmatched
	entries are displayed as "[other]".
	- cpu: cpu number the task ran at the time of sample
	- socket: processor socket number the task ran at the time of sample
	- parallelism: number of running threads at the time of sample
	- srcline: filename and line number executed at the time of sample.  The
	DWARF debugging info must be provided.
	- srcfile: file name of the source file of the samples. Requires dwarf
	information.
	- weight: Event specific weight, e.g. memory latency or transaction
	abort cost. This is the global weight.
	- local_weight: Local weight version of the weight above.
	- cgroup_id: ID derived from cgroup namespace device and inode numbers.
	- cgroup: cgroup pathname in the cgroupfs.
	- transaction: Transaction abort flags.
	- overhead: CPU overhead percentage of sample.
	- latency: latency (wall-clock) overhead percentage of sample.
	  See the `CPU and latency overheads' section for more details.
	- overhead_sys: CPU overhead percentage of sample running in system mode
	- overhead_us: CPU overhead percentage of sample running in user mode
	- overhead_guest_sys: CPU overhead percentage of sample running in system mode
	on guest machine
	- overhead_guest_us: CPU overhead percentage of sample running in user mode on
	guest machine
	- sample: Number of sample
	- period: Raw number of event count of sample
	- time: Separate the samples by time stamp with the resolution specified by
	--time-quantum (default 100ms). Specify with overhead and before it.
	- code_page_size: the code page size of sampled code address (ip)
	- ins_lat: Instruction latency in core cycles. This is the global instruction
	  latency
	- local_ins_lat: Local instruction latency version
	- p_stage_cyc: On powerpc, this presents the number of cycles spent in a
	  pipeline stage. And currently supported only on powerpc.
	- addr: (Full) virtual address of the sampled instruction
	- retire_lat: On X86, this reports pipeline stall of this instruction compared
	  to the previous instruction in cycles. And currently supported only on X86
	- simd: Flags describing a SIMD operation. "e" for empty Arm SVE predicate. "p" for partial Arm SVE predicate
	- type: Data type of sample memory access.
	- typeoff: Offset in the data type of sample memory access.
	- symoff: Offset in the symbol.
	- weight1: Average value of event specific weight (1st field of weight_struct).
	- weight2: Average value of event specific weight (2nd field of weight_struct).
	- weight3: Average value of event specific weight (3rd field of weight_struct).

	By default, overhead, comm, dso and symbol keys are used.
	(i.e. --sort overhead,comm,dso,symbol).

	If --branch-stack option is used, following sort keys are also
	available:

	- dso_from: name of library or module branched from
	- dso_to: name of library or module branched to
	- symbol_from: name of function branched from
	- symbol_to: name of function branched to
	- srcline_from: source file and line branched from
	- srcline_to: source file and line branched to
	- mispredict: "N" for predicted branch, "Y" for mispredicted branch
	- in_tx: branch in TSX transaction
	- abort: TSX transaction abort.
	- cycles: Cycles in basic block

	And default sort keys are changed to comm, dso_from, symbol_from, dso_to
	and symbol_to, see '--branch-stack'.

	When the sort key symbol is specified, columns "IPC" and "IPC Coverage"
	are enabled automatically. Column "IPC" reports the average IPC per function
	and column "IPC coverage" reports the percentage of instructions with
	sampled IPC in this function. IPC means Instruction Per Cycle. If it's low,
	it indicates there may be a performance bottleneck when the function is
	executed, such as a memory access bottleneck. If a function has high overhead
	and low IPC, it's worth further analyzing it to optimize its performance.

	If the --mem-mode option is used, the following sort keys are also available
	(incompatible with --branch-stack):
	symbol_daddr, dso_daddr, locked, tlb, mem, snoop, dcacheline, blocked.

	- symbol_daddr: name of data symbol being executed on at the time of sample
	- dso_daddr: name of library or module containing the data being executed
	on at the time of the sample
	- locked: whether the bus was locked at the time of the sample
	- tlb: type of tlb access for the data at the time of the sample
	- mem: type of memory access for the data at the time of the sample
	- snoop: type of snoop (if any) for the data at the time of the sample
	- dcacheline: the cacheline the data address is on at the time of the sample
	- phys_daddr: physical address of data being executed on at the time of sample
	- data_page_size: the data page size of data being executed on at the time of sample
	- blocked: reason of blocked load access for the data at the time of the sample

	And the default sort keys are changed to local_weight, mem, sym, dso,
	symbol_daddr, dso_daddr, snoop, tlb, locked, blocked, local_ins_lat,
	see '--mem-mode'.

	If the data file has tracepoint event(s), following (dynamic) sort keys
	are also available:
	trace, trace_fields, [<event>.]<field>[/raw]

	- trace: pretty printed trace output in a single column
	- trace_fields: fields in tracepoints in separate columns
	- <field name>: optional event and field name for a specific field

	The last form consists of event and field names.  If event name is
	omitted, it searches all events for matching field name.  The matched
	field will be shown only for the event has the field.  The event name
	supports substring match so user doesn't need to specify full subsystem
	and event name everytime.  For example, 'sched:sched_switch' event can
	be shortened to 'switch' as long as it's not ambiguous.  Also event can
	be specified by its index (starting from 1) preceded by the '%'.
	So '%1' is the first event, '%2' is the second, and so on.

	The field name can have '/raw' suffix which disables pretty printing
	and shows raw field value like hex numbers.  The --raw-trace option
	has the same effect for all dynamic sort keys.

	The default sort keys are changed to 'trace' if all events in the data
	file are tracepoint.

-F::
--fields=::
	Specify output field - multiple keys can be specified in CSV format.
	Following fields are available:
	overhead, latency, overhead_sys, overhead_us, overhead_children, sample,
	period, weight1, weight2, weight3, ins_lat, p_stage_cyc and retire_lat.
	The last 3 names are alias for the corresponding weights.  When the weight
	fields are used, they will show the average value of the weight.

	Also it can contain any sort key(s).

	By default, every sort keys not specified in -F will be appended
	automatically.

	If the keys starts with a prefix '+', then it will append the specified
        field(s) to the default field order. For example: perf report -F +period,sample.

-p::
--parent=<regex>::
        A regex filter to identify parent. The parent is a caller of this
	function and searched through the callchain, thus it requires callchain
	information recorded. The pattern is in the extended regex format and
	defaults to "\^sys_|^do_page_fault", see '--sort parent'.

-x::
--exclude-other::
        Only display entries with parent-match.

-w::
--column-widths=<width[,width...]>::
	Force each column width to the provided list, for large terminal
	readability.  0 means no limit (default behavior).

-t::
--field-separator=::
	Use a special separator character and don't pad with spaces, replacing
	all occurrences of this separator in symbol names (and other output)
	with a '.' character, that thus it's the only non valid separator.

-D::
--dump-raw-trace::
        Dump raw trace in ASCII.

--disable-order::
	Disable raw trace ordering.

-g::
--call-graph=<print_type,threshold[,print_limit],order,sort_key[,branch],value>::
        Display call chains using type, min percent threshold, print limit,
	call order, sort key, optional branch and value.  Note that ordering
	is not fixed so any parameter can be given in an arbitrary order.
	One exception is the print_limit which should be preceded by threshold.

	print_type can be either:
	- flat: single column, linear exposure of call chains.
	- graph: use a graph tree, displaying absolute overhead rates. (default)
	- fractal: like graph, but displays relative rates. Each branch of
		 the tree is considered as a new profiled object.
	- folded: call chains are displayed in a line, separated by semicolons
	- none: disable call chain display.

	threshold is a percentage value which specifies a minimum percent to be
	included in the output call graph.  Default is 0.5 (%).

	print_limit is only applied when stdio interface is used.  It's to limit
	number of call graph entries in a single hist entry.  Note that it needs
	to be given after threshold (but not necessarily consecutive).
	Default is 0 (unlimited).

	order can be either:
	- callee: callee based call graph.
	- caller: inverted caller based call graph.
	Default is 'caller' when --children is used, otherwise 'callee'.

	sort_key can be:
	- function: compare on functions (default)
	- address: compare on individual code addresses
	- srcline: compare on source filename and line number

	branch can be:
	- branch: include last branch information in callgraph when available.
	          Usually more convenient to use --branch-history for this.

	value can be:
	- percent: display overhead percent (default)
	- period: display event period
	- count: display event count

--children::
	Accumulate callchain of children to parent entry so that then can
	show up in the output.  The output will have a new "Children" column
	and will be sorted on the data.  It requires callchains are recorded.
	See the `Overhead calculation' section for more details. Enabled by
	default, disable with --no-children.

--max-stack::
	Set the stack depth limit when parsing the callchain, anything
	beyond the specified depth will be ignored. This is a trade-off
	between information loss and faster processing especially for
	workloads that can have a very long callchain stack.
	Note that when using the --itrace option the synthesized callchain size
	will override this value if the synthesized callchain size is bigger.

	Default: 127

-G::
--inverted::
        alias for inverted caller based call graph.

--ignore-callees=<regex>::
        Ignore callees of the function(s) matching the given regex.
        This has the effect of collecting the callers of each such
        function into one place in the call-graph tree.

--pretty=<key>::
        Pretty printing style.  key: normal, raw

--stdio:: Use the stdio interface.

--stdio-color::
	'always', 'never' or 'auto', allowing configuring color output
	via the command line, in addition to via "color.ui" .perfconfig.
	Use '--stdio-color always' to generate color even when redirecting
	to a pipe or file. Using just '--stdio-color' is equivalent to
	using 'always'.

--tui:: Use the TUI interface, that is integrated with annotate and allows
        zooming into DSOs or threads, among other features. Use of --tui
	requires a tty, if one is not present, as when piping to other
	commands, the stdio interface is used.

--gtk:: Use the GTK2 interface.

-k::
--vmlinux=<file>::
        vmlinux pathname

--ignore-vmlinux::
	Ignore vmlinux files.

--kallsyms=<file>::
        kallsyms pathname

-m::
--modules::
        Load module symbols. WARNING: This should only be used with -k and
        a LIVE kernel.

-f::
--force::
        Don't do ownership validation.

--symfs=<directory>::
        Look for files with symbols relative to this directory.

-C::
--cpu:: Only report samples for the list of CPUs provided. Multiple CPUs can
	be provided as a comma-separated list with no space: 0,1. Ranges of
	CPUs are specified with -: 0-2. Default is to report samples on all
	CPUs.

-M::
--disassembler-style=:: Set disassembler style for objdump.

--source::
	Interleave source code with assembly code. Enabled by default,
	disable with --no-source.

--asm-raw::
	Show raw instruction encoding of assembly instructions.

--show-total-period:: Show a column with the sum of periods.

-I::
--show-info::
	Display extended information about the perf.data file. This adds
	information which may be very large and thus may clutter the display.
	It currently includes: cpu and numa topology of the host system.

-b::
--branch-stack::
	Use the addresses of sampled taken branches instead of the instruction
	address to build the histograms. To generate meaningful output, the
	perf.data file must have been obtained using perf record -b or
	perf record --branch-filter xxx where xxx is a branch filter option.
	perf report is able to auto-detect whether a perf.data file contains
	branch stacks and it will automatically switch to the branch view mode,
	unless --no-branch-stack is used.

--branch-history::
	Add the addresses of sampled taken branches to the callstack.
	This allows to examine the path the program took to each sample.
	The data collection must have used -b (or -j) and -g.

	Also show with some branch flags that can be:
	- Predicted: display the average percentage of predicated branches.
		     (predicated number / total number)
	- Abort: display the number of tsx aborted branches.
	- Cycles: cycles in basic block.

	- iterations: display the average number of iterations in callchain list.

--addr2line=<path>::
        Path to addr2line binary.

--objdump=<path>::
        Path to objdump binary.

--prefix=PREFIX::
--prefix-strip=N::
	Remove first N entries from source file path names in executables
	and add PREFIX. This allows to display source code compiled on systems
	with different file system layout.

--group::
	Show event group information together. It forces group output also
	if there are no groups defined in data file.

--group-sort-idx::
	Sort the output by the event at the index n in group. If n is invalid,
	sort by the first event. It can support multiple groups with different
	amount of events. WARNING: This should be used on grouped events.

--demangle::
	Demangle symbol names to human readable form. It's enabled by default,
	disable with --no-demangle.

--demangle-kernel::
	Demangle kernel symbol names to human readable form (for C++ kernels).

--mem-mode::
	Use the data addresses of samples in addition to instruction addresses
	to build the histograms.  To generate meaningful output, the perf.data
	file must have been obtained using perf record -d -W and using a
	special event -e cpu/mem-loads/p or -e cpu/mem-stores/p. See
	'perf mem' for simpler access.

--percent-limit::
	Do not show entries which have an overhead under that percent.
	(Default: 0).  Note that this option also sets the percent limit (threshold)
	of callchains.  However the default value of callchain threshold is
	different than the default value of hist entries.  Please see the
	--call-graph option for details.

--percentage::
	Determine how to display the CPU and latency overhead percentage
	of filtered entries. Filters can be applied by --comms, --dsos, --symbols
	and/or --parallelism options and Zoom operations on the TUI (thread, dso, etc).

	"relative" means it's relative to filtered entries only so that the
	sum of shown entries will be always 100%.  "absolute" means it retains
	the original value before and after the filter is applied.

--header::
	Show header information in the perf.data file.  This includes
	various information like hostname, OS and perf version, cpu/mem
	info, perf command line, event list and so on.  Currently only
	--stdio output supports this feature.

--header-only::
	Show only perf.data header (forces --stdio).

--time::
	Only analyze samples within given time window: <start>,<stop>. Times
	have the format seconds.nanoseconds. If start is not given (i.e. time
	string is ',x.y') then analysis starts at the beginning of the file. If
	stop time is not given (i.e. time string is 'x.y,') then analysis goes
	to end of file. Multiple ranges can be separated by spaces, which
	requires the argument to be quoted e.g. --time "1234.567,1234.789 1235,"

	Also support time percent with multiple time ranges. Time string is
	'a%/n,b%/m,...' or 'a%-b%,c%-%d,...'.

	For example:
	Select the second 10% time slice:

	  perf report --time 10%/2

	Select from 0% to 10% time slice:

	  perf report --time 0%-10%

	Select the first and second 10% time slices:

	  perf report --time 10%/1,10%/2

	Select from 0% to 10% and 30% to 40% slices:

	  perf report --time 0%-10%,30%-40%

--switch-on EVENT_NAME::
	Only consider events after this event is found.

	This may be interesting to measure a workload only after some initialization
	phase is over, i.e. insert a perf probe at that point and then using this
	option with that probe.

--switch-off EVENT_NAME::
	Stop considering events after this event is found.

--show-on-off-events::
	Show the --switch-on/off events too. This has no effect in 'perf report' now
	but probably we'll make the default not to show the switch-on/off events
        on the --group mode and if there is only one event besides the off/on ones,
	go straight to the histogram browser, just like 'perf report' with no events
	explicitly specified does.

--itrace::
	Options for decoding instruction tracing data. The options are:

include::itrace.txt[]

	To disable decoding entirely, use --no-itrace.

--full-source-path::
	Show the full path for source files for srcline output.

--show-ref-call-graph::
	When multiple events are sampled, it may not be needed to collect
	callgraphs for all of them. The sample sites are usually nearby,
	and it's enough to collect the callgraphs on a reference event.
	So user can use "call-graph=no" event modifier to disable callgraph
	for other events to reduce the overhead.
	However, perf report cannot show callgraphs for the event which
	disable the callgraph.
	This option extends the perf report to show reference callgraphs,
	which collected by reference event, in no callgraph event.

--stitch-lbr::
	Show callgraph with stitched LBRs, which may have more complete
	callgraph. The perf.data file must have been obtained using
	perf record --call-graph lbr.
	Disabled by default. In common cases with call stack overflows,
	it can recreate better call stacks than the default lbr call stack
	output. But this approach is not foolproof. There can be cases
	where it creates incorrect call stacks from incorrect matches.
	The known limitations include exception handing such as
	setjmp/longjmp will have calls/returns not match.

--socket-filter::
	Only report the samples on the processor socket that match with this filter

--samples=N::
	Save N individual samples for each histogram entry to show context in perf
	report tui browser.

--raw-trace::
	When displaying traceevent output, do not use print fmt or plugins.

-H::
--hierarchy::
	Enable hierarchical output.  In the hierarchy mode, each sort key groups
	samples based on the criteria and then sub-divide it using the lower
	level sort key.

	For example:
	In normal output:

	  perf report -s dso,sym
	  # Overhead  Shared Object      Symbol
	      50.00%  [kernel.kallsyms]  [k] kfunc1
	      20.00%  perf               [.] foo
	      15.00%  [kernel.kallsyms]  [k] kfunc2
	      10.00%  perf               [.] bar
	       5.00%  libc.so            [.] libcall

	In hierarchy output:

	  perf report -s dso,sym --hierarchy
	  #   Overhead  Shared Object / Symbol
	      65.00%    [kernel.kallsyms]
	        50.00%    [k] kfunc1
	        15.00%    [k] kfunc2
	      30.00%    perf
	        20.00%    [.] foo
	        10.00%    [.] bar
	       5.00%    libc.so
	         5.00%    [.] libcall

--inline::
	If a callgraph address belongs to an inlined function, the inline stack
	will be printed. Each entry is function name or file/line. Enabled by
	default, disable with --no-inline.

--mmaps::
	Show --tasks output plus mmap information in a format similar to
	/proc/<PID>/maps.

	Please note that not all mmaps are stored, options affecting which ones
	are include 'perf record --data', for instance.

--ns::
	Show time stamps in nanoseconds.

--stats::
	Display overall events statistics without any further processing.
	(like the one at the end of the perf report -D command)

--tasks::
	Display monitored tasks stored in perf data. Displaying pid/tid/ppid
	plus the command string aligned to distinguish parent and child tasks.

--percent-type::
	Set annotation percent type from following choices:
	  global-period, local-period, global-hits, local-hits

	The local/global keywords set if the percentage is computed
	in the scope of the function (local) or the whole data (global).
	The period/hits keywords set the base the percentage is computed
	on - the samples period or the number of samples (hits).

--time-quantum::
	Configure time quantum for time sort key. Default 100ms.
	Accepts s, us, ms, ns units.

--total-cycles::
	When --total-cycles is specified, it supports sorting for all blocks by
	'Sampled Cycles%'. This is useful to concentrate on the globally hottest
	blocks. In output, there are some new columns:

	'Sampled Cycles%' - block sampled cycles aggregation / total sampled cycles
	'Sampled Cycles'  - block sampled cycles aggregation
	'Avg Cycles%'     - block average sampled cycles / sum of total block average
			    sampled cycles
	'Avg Cycles'      - block average sampled cycles
	'Branch Counter'  - block branch counter histogram (with -v showing the number)

--skip-empty::
	Do not print 0 results in the --stat output.

include::cpu-and-latency-overheads.txt[]

include::callchain-overhead-calculation.txt[]

SEE ALSO
--------
linkperf:perf-stat[1], linkperf:perf-annotate[1], linkperf:perf-record[1],
linkperf:perf-intel-pt[1]