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48d02a1d5c
Implement printing instruction sequences as hex dump for branch stacks. This relies on the x86 instruction decoder used by the PT decoder to find the lengths of instructions to dump them individually. This is good enough for pattern matching. This allows to study hot paths for individual samples, together with branch misprediction and cycle count / IPC information if available (on Skylake systems). % perf record -b ... % perf script -F brstackinsn ... read_hpet+67: ffffffff9905b843 insn: 74 ea # PRED ffffffff9905b82f insn: 85 c9 ffffffff9905b831 insn: 74 12 ffffffff9905b833 insn: f3 90 ffffffff9905b835 insn: 48 8b 0f ffffffff9905b838 insn: 48 89 ca ffffffff9905b83b insn: 48 c1 ea 20 ffffffff9905b83f insn: 39 f2 ffffffff9905b841 insn: 89 d0 ffffffff9905b843 insn: 74 ea # PRED Only works when no special branch filters are specified. Occasionally the path does not reach up to the sample IP, as the LBRs may be frozen before executing a final jump. In this case we print a special message. The instruction dumper piggy backs on the existing infrastructure from the IP PT decoder. An earlier iteration of this patch relied on a disassembler, but this version only uses the existing instruction decoder. Committer note: Added hint about how to get suitable perf.data files for use with '-F brstackinsm': $ perf record usleep 1 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.018 MB perf.data (8 samples) ] $ $ perf script -F brstackinsn Display of branch stack assembler requested, but non all-branch filter set Hint: run 'perf record -b ...' $ Signed-off-by: Andi Kleen <ak@linux.intel.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Link: http://lkml.kernel.org/r/20170223234634.583-1-andi@firstfloor.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
318 lines
11 KiB
Plaintext
318 lines
11 KiB
Plaintext
perf-script(1)
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=============
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NAME
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----
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perf-script - Read perf.data (created by perf record) and display trace output
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SYNOPSIS
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--------
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[verse]
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'perf script' [<options>]
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'perf script' [<options>] record <script> [<record-options>] <command>
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'perf script' [<options>] report <script> [script-args]
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'perf script' [<options>] <script> <required-script-args> [<record-options>] <command>
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'perf script' [<options>] <top-script> [script-args]
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DESCRIPTION
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-----------
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This command reads the input file and displays the trace recorded.
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There are several variants of perf script:
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'perf script' to see a detailed trace of the workload that was
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recorded.
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You can also run a set of pre-canned scripts that aggregate and
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summarize the raw trace data in various ways (the list of scripts is
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available via 'perf script -l'). The following variants allow you to
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record and run those scripts:
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'perf script record <script> <command>' to record the events required
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for 'perf script report'. <script> is the name displayed in the
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output of 'perf script --list' i.e. the actual script name minus any
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language extension. If <command> is not specified, the events are
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recorded using the -a (system-wide) 'perf record' option.
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'perf script report <script> [args]' to run and display the results
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of <script>. <script> is the name displayed in the output of 'perf
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script --list' i.e. the actual script name minus any language
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extension. The perf.data output from a previous run of 'perf script
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record <script>' is used and should be present for this command to
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succeed. [args] refers to the (mainly optional) args expected by
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the script.
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'perf script <script> <required-script-args> <command>' to both
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record the events required for <script> and to run the <script>
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using 'live-mode' i.e. without writing anything to disk. <script>
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is the name displayed in the output of 'perf script --list' i.e. the
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actual script name minus any language extension. If <command> is
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not specified, the events are recorded using the -a (system-wide)
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'perf record' option. If <script> has any required args, they
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should be specified before <command>. This mode doesn't allow for
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optional script args to be specified; if optional script args are
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desired, they can be specified using separate 'perf script record'
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and 'perf script report' commands, with the stdout of the record step
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piped to the stdin of the report script, using the '-o -' and '-i -'
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options of the corresponding commands.
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'perf script <top-script>' to both record the events required for
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<top-script> and to run the <top-script> using 'live-mode'
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i.e. without writing anything to disk. <top-script> is the name
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displayed in the output of 'perf script --list' i.e. the actual
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script name minus any language extension; a <top-script> is defined
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as any script name ending with the string 'top'.
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[<record-options>] can be passed to the record steps of 'perf script
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record' and 'live-mode' variants; this isn't possible however for
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<top-script> 'live-mode' or 'perf script report' variants.
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See the 'SEE ALSO' section for links to language-specific
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information on how to write and run your own trace scripts.
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OPTIONS
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-------
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<command>...::
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Any command you can specify in a shell.
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-D::
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--dump-raw-trace=::
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Display verbose dump of the trace data.
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-L::
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--Latency=::
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Show latency attributes (irqs/preemption disabled, etc).
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-l::
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--list=::
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Display a list of available trace scripts.
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-s ['lang']::
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--script=::
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Process trace data with the given script ([lang]:script[.ext]).
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If the string 'lang' is specified in place of a script name, a
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list of supported languages will be displayed instead.
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-g::
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--gen-script=::
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Generate perf-script.[ext] starter script for given language,
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using current perf.data.
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-a::
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Force system-wide collection. Scripts run without a <command>
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normally use -a by default, while scripts run with a <command>
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normally don't - this option allows the latter to be run in
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system-wide mode.
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-i::
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--input=::
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Input file name. (default: perf.data unless stdin is a fifo)
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-d::
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--debug-mode::
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Do various checks like samples ordering and lost events.
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-F::
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--fields::
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Comma separated list of fields to print. Options are:
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comm, tid, pid, time, cpu, event, trace, ip, sym, dso, addr, symoff,
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srcline, period, iregs, brstack, brstacksym, flags, bpf-output, brstackinsn,
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callindent, insn, insnlen. Field list can be prepended with the type, trace, sw or hw,
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to indicate to which event type the field list applies.
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e.g., -F sw:comm,tid,time,ip,sym and -F trace:time,cpu,trace
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perf script -F <fields>
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is equivalent to:
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perf script -F trace:<fields> -F sw:<fields> -F hw:<fields>
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i.e., the specified fields apply to all event types if the type string
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is not given.
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The arguments are processed in the order received. A later usage can
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reset a prior request. e.g.:
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-F trace: -F comm,tid,time,ip,sym
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The first -F suppresses trace events (field list is ""), but then the
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second invocation sets the fields to comm,tid,time,ip,sym. In this case a
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warning is given to the user:
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"Overriding previous field request for all events."
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Alternatively, consider the order:
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-F comm,tid,time,ip,sym -F trace:
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The first -F sets the fields for all events and the second -F
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suppresses trace events. The user is given a warning message about
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the override, and the result of the above is that only S/W and H/W
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events are displayed with the given fields.
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For the 'wildcard' option if a user selected field is invalid for an
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event type, a message is displayed to the user that the option is
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ignored for that type. For example:
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$ perf script -F comm,tid,trace
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'trace' not valid for hardware events. Ignoring.
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'trace' not valid for software events. Ignoring.
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Alternatively, if the type is given an invalid field is specified it
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is an error. For example:
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perf script -v -F sw:comm,tid,trace
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'trace' not valid for software events.
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At this point usage is displayed, and perf-script exits.
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The flags field is synthesized and may have a value when Instruction
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Trace decoding. The flags are "bcrosyiABEx" which stand for branch,
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call, return, conditional, system, asynchronous, interrupt,
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transaction abort, trace begin, trace end, and in transaction,
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respectively. Known combinations of flags are printed more nicely e.g.
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"call" for "bc", "return" for "br", "jcc" for "bo", "jmp" for "b",
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"int" for "bci", "iret" for "bri", "syscall" for "bcs", "sysret" for "brs",
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"async" for "by", "hw int" for "bcyi", "tx abrt" for "bA", "tr strt" for "bB",
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"tr end" for "bE". However the "x" flag will be display separately in those
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cases e.g. "jcc (x)" for a condition branch within a transaction.
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The callindent field is synthesized and may have a value when
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Instruction Trace decoding. For calls and returns, it will display the
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name of the symbol indented with spaces to reflect the stack depth.
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When doing instruction trace decoding insn and insnlen give the
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instruction bytes and the instruction length of the current
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instruction.
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Finally, a user may not set fields to none for all event types.
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i.e., -F "" is not allowed.
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The brstack output includes branch related information with raw addresses using the
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/v/v/v/v/cycles syntax in the following order:
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FROM: branch source instruction
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TO : branch target instruction
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M/P/-: M=branch target mispredicted or branch direction was mispredicted, P=target predicted or direction predicted, -=not supported
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X/- : X=branch inside a transactional region, -=not in transaction region or not supported
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A/- : A=TSX abort entry, -=not aborted region or not supported
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cycles
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The brstacksym is identical to brstack, except that the FROM and TO addresses are printed in a symbolic form if possible.
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When brstackinsn is specified the full assembler sequences of branch sequences for each sample
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is printed. This is the full execution path leading to the sample. This is only supported when the
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sample was recorded with perf record -b or -j any.
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-k::
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--vmlinux=<file>::
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vmlinux pathname
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--kallsyms=<file>::
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kallsyms pathname
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--symfs=<directory>::
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Look for files with symbols relative to this directory.
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-G::
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--hide-call-graph::
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When printing symbols do not display call chain.
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--stop-bt::
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Stop display of callgraph at these symbols
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-C::
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--cpu:: Only report samples for the list of CPUs provided. Multiple CPUs can
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be provided as a comma-separated list with no space: 0,1. Ranges of
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CPUs are specified with -: 0-2. Default is to report samples on all
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CPUs.
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-c::
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--comms=::
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Only display events for these comms. CSV that understands
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file://filename entries.
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--pid=::
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Only show events for given process ID (comma separated list).
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--tid=::
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Only show events for given thread ID (comma separated list).
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-I::
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--show-info::
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Display extended information about the perf.data file. This adds
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information which may be very large and thus may clutter the display.
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It currently includes: cpu and numa topology of the host system.
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It can only be used with the perf script report mode.
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--show-kernel-path::
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Try to resolve the path of [kernel.kallsyms]
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--show-task-events
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Display task related events (e.g. FORK, COMM, EXIT).
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--show-mmap-events
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Display mmap related events (e.g. MMAP, MMAP2).
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--show-namespace-events
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Display namespace events i.e. events of type PERF_RECORD_NAMESPACES.
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--show-switch-events
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Display context switch events i.e. events of type PERF_RECORD_SWITCH or
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PERF_RECORD_SWITCH_CPU_WIDE.
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--demangle::
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Demangle symbol names to human readable form. It's enabled by default,
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disable with --no-demangle.
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--demangle-kernel::
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Demangle kernel symbol names to human readable form (for C++ kernels).
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--header
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Show perf.data header.
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--header-only
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Show only perf.data header.
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--itrace::
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Options for decoding instruction tracing data. The options are:
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include::itrace.txt[]
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To disable decoding entirely, use --no-itrace.
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--full-source-path::
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Show the full path for source files for srcline output.
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--max-stack::
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Set the stack depth limit when parsing the callchain, anything
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beyond the specified depth will be ignored. This is a trade-off
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between information loss and faster processing especially for
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workloads that can have a very long callchain stack.
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Note that when using the --itrace option the synthesized callchain size
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will override this value if the synthesized callchain size is bigger.
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Default: 127
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--ns::
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Use 9 decimal places when displaying time (i.e. show the nanoseconds)
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-f::
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--force::
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Don't do ownership validation.
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--time::
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Only analyze samples within given time window: <start>,<stop>. Times
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have the format seconds.microseconds. If start is not given (i.e., time
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string is ',x.y') then analysis starts at the beginning of the file. If
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stop time is not given (i.e, time string is 'x.y,') then analysis goes
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to end of file.
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--max-blocks::
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Set the maximum number of program blocks to print with brstackasm for
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each sample.
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SEE ALSO
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--------
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linkperf:perf-record[1], linkperf:perf-script-perl[1],
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linkperf:perf-script-python[1]
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