perf callchain: Stop validating callchains by the max_stack sysctl

[linux-2.6-block.git] / tools / perf / Documentation / perf-script.txt

perf-script(1)
=============

NAME
----
perf-script - Read perf.data (created by perf record) and display trace output

SYNOPSIS
--------
[verse]
'perf script' [<options>]
'perf script' [<options>] record <script> [<record-options>] <command>
'perf script' [<options>] report <script> [script-args]
'perf script' [<options>] <script> <required-script-args> [<record-options>] <command>
'perf script' [<options>] <top-script> [script-args]

DESCRIPTION
-----------
This command reads the input file and displays the trace recorded.

There are several variants of perf script:

  'perf script' to see a detailed trace of the workload that was
  recorded.

  You can also run a set of pre-canned scripts that aggregate and
  summarize the raw trace data in various ways (the list of scripts is
  available via 'perf script -l').  The following variants allow you to
  record and run those scripts:

  'perf script record <script> <command>' to record the events required
  for 'perf script report'.  <script> is the name displayed in the
  output of 'perf script --list' i.e. the actual script name minus any
  language extension.  If <command> is not specified, the events are
  recorded using the -a (system-wide) 'perf record' option.

  'perf script report <script> [args]' to run and display the results
  of <script>.  <script> is the name displayed in the output of 'perf
  trace --list' i.e. the actual script name minus any language
  extension.  The perf.data output from a previous run of 'perf script
  record <script>' is used and should be present for this command to
  succeed.  [args] refers to the (mainly optional) args expected by
  the script.

  'perf script <script> <required-script-args> <command>' to both
  record the events required for <script> and to run the <script>
  using 'live-mode' i.e. without writing anything to disk.  <script>
  is the name displayed in the output of 'perf script --list' i.e. the
  actual script name minus any language extension.  If <command> is
  not specified, the events are recorded using the -a (system-wide)
  'perf record' option.  If <script> has any required args, they
  should be specified before <command>.  This mode doesn't allow for
  optional script args to be specified; if optional script args are
  desired, they can be specified using separate 'perf script record'
  and 'perf script report' commands, with the stdout of the record step
  piped to the stdin of the report script, using the '-o -' and '-i -'
  options of the corresponding commands.

  'perf script <top-script>' to both record the events required for
  <top-script> and to run the <top-script> using 'live-mode'
  i.e. without writing anything to disk.  <top-script> is the name
  displayed in the output of 'perf script --list' i.e. the actual
  script name minus any language extension; a <top-script> is defined
  as any script name ending with the string 'top'.

  [<record-options>] can be passed to the record steps of 'perf script
  record' and 'live-mode' variants; this isn't possible however for
  <top-script> 'live-mode' or 'perf script report' variants.

  See the 'SEE ALSO' section for links to language-specific
  information on how to write and run your own trace scripts.

OPTIONS
-------
<command>...::
	Any command you can specify in a shell.

-D::
--dump-raw-script=::
        Display verbose dump of the trace data.

-L::
--Latency=::
        Show latency attributes (irqs/preemption disabled, etc).

-l::
--list=::
        Display a list of available trace scripts.

-s ['lang']::
--script=::
        Process trace data with the given script ([lang]:script[.ext]).
	If the string 'lang' is specified in place of a script name, a
        list of supported languages will be displayed instead.

-g::
--gen-script=::
        Generate perf-script.[ext] starter script for given language,
        using current perf.data.

-a::
        Force system-wide collection.  Scripts run without a <command>
        normally use -a by default, while scripts run with a <command>
        normally don't - this option allows the latter to be run in
        system-wide mode.

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

-d::
--debug-mode::
        Do various checks like samples ordering and lost events.

-F::
--fields::
        Comma separated list of fields to print. Options are:
        comm, tid, pid, time, cpu, event, trace, ip, sym, dso, addr, symoff,
	srcline, period, iregs, brstack, brstacksym, flags.
        Field list can be prepended with the type, trace, sw or hw,
        to indicate to which event type the field list applies.
        e.g., -f sw:comm,tid,time,ip,sym  and -f trace:time,cpu,trace

		perf script -f <fields>

	is equivalent to:

		perf script -f trace:<fields> -f sw:<fields> -f hw:<fields>

	i.e., the specified fields apply to all event types if the type string
	is not given.

	The arguments are processed in the order received. A later usage can
	reset a prior request. e.g.:

		-f trace: -f comm,tid,time,ip,sym

	The first -f suppresses trace events (field list is ""), but then the
	second invocation sets the fields to comm,tid,time,ip,sym. In this case a
	warning is given to the user:

		"Overriding previous field request for all events."

	Alternatively, consider the order:

		-f comm,tid,time,ip,sym -f trace:

	The first -f sets the fields for all events and the second -f
	suppresses trace events. The user is given a warning message about
	the override, and the result of the above is that only S/W and H/W
	events are displayed with the given fields.

	For the 'wildcard' option if a user selected field is invalid for an
	event type, a message is displayed to the user that the option is
	ignored for that type. For example:

		$ perf script -f comm,tid,trace
		'trace' not valid for hardware events. Ignoring.
		'trace' not valid for software events. Ignoring.

	Alternatively, if the type is given an invalid field is specified it
	is an error. For example:

        perf script -v -f sw:comm,tid,trace
        'trace' not valid for software events.

	At this point usage is displayed, and perf-script exits.

	The flags field is synthesized and may have a value when Instruction
	Trace decoding. The flags are "bcrosyiABEx" which stand for branch,
	call, return, conditional, system, asynchronous, interrupt,
	transaction abort, trace begin, trace end, and in transaction,
	respectively.

	Finally, a user may not set fields to none for all event types.
	i.e., -f "" is not allowed.

	The brstack output includes branch related information with raw addresses using the
	/v/v/v/v/ syntax in the following order:
	FROM: branch source instruction
	TO  : branch target instruction
        M/P/-: M=branch target mispredicted or branch direction was mispredicted, P=target predicted or direction predicted, -=not supported
	X/- : X=branch inside a transactional region, -=not in transaction region or not supported
	A/- : A=TSX abort entry, -=not aborted region or not supported

	The brstacksym is identical to brstack, except that the FROM and TO addresses are printed in a symbolic form if possible.

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

--kallsyms=<file>::
        kallsyms pathname

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

-G::
--hide-call-graph::
        When printing symbols do not display call chain.

-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.

-c::
--comms=::
	Only display events for these comms. CSV that understands
	file://filename entries.

--pid=::
	Only show events for given process ID (comma separated list).

--tid=::
	Only show events for given thread ID (comma separated list).

-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.
	It can only be used with the perf script report mode.

--show-kernel-path::
	Try to resolve the path of [kernel.kallsyms]

--show-task-events
	Display task related events (e.g. FORK, COMM, EXIT).

--show-mmap-events
	Display mmap related events (e.g. MMAP, MMAP2).

--show-switch-events
	Display context switch events i.e. events of type PERF_RECORD_SWITCH or
	PERF_RECORD_SWITCH_CPU_WIDE.

--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).

--header
	Show perf.data header.

--header-only
	Show only perf.data header.

--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.

--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: /proc/sys/kernel/perf_event_max_stack when present, 127 otherwise.

--ns::
	Use 9 decimal places when displaying time (i.e. show the nanoseconds)

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

SEE ALSO
--------
linkperf:perf-record[1], linkperf:perf-script-perl[1],
linkperf:perf-script-python[1]