perf-report(1) — Linux manual page


PERF-REPORT(1)                 perf Manual                PERF-REPORT(1)

NAME         top

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

SYNOPSIS         top

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

DESCRIPTION         top

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

OPTIONS         top

       -i, --input=
           Input file name. (default: 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 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 column. See --percentage for more

           Only show events for given process ID (comma separated list).

           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 column. See --percentage for more

       -S, --symbols=
           Only consider these symbols. CSV that understands
           file://filename entries. This option will affect the
           percentage of the overhead column. See --percentage for more

           Only show symbols that match (partially) with this filter.

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

       -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

           •   pid: command and tid of the task

           •   dso: name of library or module executed at the time of

           •   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

           •   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

           •   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: Overhead percentage of sample

           •   overhead_sys: Overhead percentage of sample running in
               system mode

           •   overhead_us: Overhead percentage of sample running in
               user mode

           •   overhead_guest_sys: Overhead percentage of sample running
               in system mode on guest machine

           •   overhead_guest_us: 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

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

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

           •   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

           •   tlb: type of tlb access for the data at the time of the

           •   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,
           overhead_sys, overhead_us, overhead_children, sample and
           period. Also it can contain any sort key(s).

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

               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 raw trace ordering.

           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

           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

           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 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 printing style. key: normal, raw

           Use the stdio interface.

           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.

           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.

           Use the GTK2 interface.

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

           Ignore vmlinux files.

           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.

           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.

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

           Show raw instruction encoding of assembly instructions.

           Show a column with the sum of periods.

       -I, --show-info
           Display extended information about the 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 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 file contains branch stacks
           and it will automatically switch to the branch view mode,
           unless --no-branch-stack is used.

           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.

           Path to addr2line binary.

           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.

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

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

           Demangle kernel symbol names to human readable form (for C++

           Use the data addresses of samples in addition to instruction
           addresses to build the histograms. To generate meaningful
           output, the 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.

           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

           Determine how to display the overhead percentage of filtered
           entries. Filters can be applied by --comms, --dsos and/or
           --symbols 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.

           Show header information in the 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.

           Show only header (forces --stdio).

           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 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.

           Options for decoding instruction tracing data. The options

               i       synthesize instructions events
               y       synthesize cycles events
               b       synthesize branches events (branch misses for Arm SPE)
               c       synthesize branches events (calls only)
               r       synthesize branches events (returns only)
               x       synthesize transactions events
               w       synthesize ptwrite events
               p       synthesize power events (incl. PSB events for Intel PT)
               o       synthesize other events recorded due to the use
                       of aux-output (refer to perf record)
               I       synthesize interrupt or similar (asynchronous) events
                       (e.g. Intel PT Event Trace)
               e       synthesize error events
               d       create a debug log
               f       synthesize first level cache events
               m       synthesize last level cache events
               M       synthesize memory events
               t       synthesize TLB events
               a       synthesize remote access events
               g       synthesize a call chain (use with i or x)
               G       synthesize a call chain on existing event records
               l       synthesize last branch entries (use with i or x)
               L       synthesize last branch entries on existing event records
               s       skip initial number of events
               q       quicker (less detailed) decoding
               A       approximate IPC
               Z       prefer to ignore timestamps (so-called "timeless" decoding)

               The default is all events i.e. the same as --itrace=iybxwpe,
               except for perf script where it is --itrace=ce

               In addition, the period (default 100000, except for perf script where it is 1)
               for instructions events can be specified in units of:

               i       instructions
               t       ticks
               ms      milliseconds
               us      microseconds
               ns      nanoseconds (default)

               Also the call chain size (default 16, max. 1024) for instructions or
               transactions events can be specified.

               Also the number of last branch entries (default 64, max. 1024) for
               instructions or transactions events can be specified.

               Similar to options g and l, size may also be specified for options G and L.
               On x86, note that G and L work poorly when data has been recorded with
               large PEBS. Refer linkperf:perf-intel-pt[1] man page for details.

               It is also possible to skip events generated (instructions, branches, transactions,
               ptwrite, power) at the beginning. This is useful to ignore initialization code.


               skips the first million instructions.

               The 'e' option may be followed by flags which affect what errors will or
               will not be reported. Each flag must be preceded by either '+' or '-'.
               The flags are:
                       o       overflow
                       l       trace data lost

               If supported, the 'd' option may be followed by flags which affect what
               debug messages will or will not be logged. Each flag must be preceded
               by either '+' or '-'. The flags are:
                       a       all perf events
                       e       output only on errors (size configurable - see linkperf:perf-config[1])
                       o       output to stdout

               If supported, the 'q' option may be repeated to increase the effect.

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

           Show the full path for source files for srcline output.

           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.

           Show callgraph with stitched LBRs, which may have more
           complete callgraph. The 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.

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

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

           When displaying traceevent output, do not use print fmt or

           Enable hierarchical output.

           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.

           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.

           Show time stamps in nanoseconds.

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

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

           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).

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

           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

               '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

           Do not print 0 results in the --stat output.


       The overhead can be shown in two columns as Children and Self
       when perf collects callchains. The self overhead is simply
       calculated by adding all period values of the entry - usually a
       function (symbol). This is the value that perf shows
       traditionally and sum of all the self overhead values should be

       The children overhead is calculated by adding all period values
       of the child functions so that it can show the total overhead of
       the higher level functions even if they don’t directly execute
       much. Children here means functions that are called from another
       (parent) function.

       It might be confusing that the sum of all the children overhead
       values exceeds 100% since each of them is already an accumulation
       of self overhead of its child functions. But with this enabled,
       users can find which function has the most overhead even if
       samples are spread over the children.

       Consider the following example; there are three functions like

           .ft C
           void foo(void) {
               /* do something */

           void bar(void) {
               /* do something */

           int main(void) {
               return 0;

       In this case foo is a child of bar, and bar is an immediate child
       of main so foo also is a child of main. In other words, main is a
       parent of foo and bar, and bar is a parent of foo.

       Suppose all samples are recorded in foo and bar only. When it’s
       recorded with callchains the output will show something like
       below in the usual (self-overhead-only) output of perf report:

           .ft C
           Overhead  Symbol
           ........  .....................
             60.00%  foo
                     --- foo

             40.00%  bar
                     --- bar

       When the --children option is enabled, the self overhead values
       of child functions (i.e. foo and bar) are added to the parents to
       calculate the children overhead. In this case the report could be
       displayed as:

           .ft C
           Children      Self  Symbol
           ........  ........  ....................
            100.00%     0.00%  __libc_start_main
                     --- __libc_start_main

            100.00%     0.00%  main
                     --- main

            100.00%    40.00%  bar
                     --- bar

             60.00%    60.00%  foo
                     --- foo

       In the above output, the self overhead of foo (60%) was add to
       the children overhead of bar, main and __libc_start_main.
       Likewise, the self overhead of bar (40%) was added to the
       children overhead of main and \_\_libc_start_main.

       So \_\_libc_start_main and main are shown first since they have
       same (100%) children overhead (even though they have zero self
       overhead) and they are the parents of foo and bar.

       Since v3.16 the children overhead is shown by default and the
       output is sorted by its values. The children overhead is disabled
       by specifying --no-children option on the command line or by
       adding report.children = false or top.children = false in the
       perf config file.

SEE ALSO         top

       perf-stat(1), perf-annotate(1), perf-record(1), perf-intel-pt(1)

COLOPHON         top

       This page is part of the perf (Performance analysis tools for
       Linux (in Linux source tree)) project.  Information about the
       project can be found at 
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       bug report for this manual page, send it to  This page was obtained from the
       project's upstream Git repository
       on 2023-12-22.  (At that time, the date of the most recent commit
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perf                           2023-04-04                 PERF-REPORT(1)

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