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

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 message. (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 info.

           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 info.

       -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 info.

           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.

               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 sample

           ·   dso_size: size of library or module executed at the time of

           ·   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

           ·   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

           ·   cgroup: cgroup pathname in the cgroupfs.

           ·   transaction: Transaction abort flags.

           ·   overhead: Overhead percentage of sample

           ·   overhead_sys: Overhead percentage of sample running in system

           ·   overhead_us: Overhead percentage of sample running in user

           ·   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.

                   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

           ·   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.

           ·   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

           ·   mem: type of memory access for the data at the time of the

           ·   snoop: type of snoop (if any) for the data at the time of the

           ·   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

                   And the default sort keys are changed to local_weight, mem, sym, dso,
                   symbol_daddr, dso_daddr, snoop, tlb, locked, 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

                   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

       -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.

           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 --no-children.

           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

               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

           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

       -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 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 details.

           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,

               "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 explicitely
           specified does.

           Options for decoding instruction tracing data. The options are:

               i       synthesize instructions 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
               o       synthesize other events recorded due to the use
                       of aux-output (refer to perf record)
               e       synthesize error events
               d       create a debug log
               f       synthesize first level cache events
               m       synthesize last level cache 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

               The default is all events i.e. the same as --itrace=ibxwpe,
               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.

               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

           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
           full proof. 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

               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 command)

           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 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


       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 100%.

       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)

       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 below.

           .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

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 ⟨⟩.  If
       you have a bug report for this manual page, send it to  This page was obtained from the
       project's upstream Git repository
       ⟨⟩ on
       2020-06-09.  (At that time, the date of the most recent commit that
       was found in the repository was 2020-06-08.)  If you discover any
       rendering problems in this HTML version of the page, or you believe
       there is a better or more up-to-date source for the page, or you have
       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to

perf                             2020-04-18                   PERF-REPORT(1)

Pages that refer to this page: perf(1)perf-annotate(1)perf-archive(1)perf-buildid-cache(1)perf-buildid-list(1)perf-diff(1)perf-evlist(1)perf-inject(1)perf-intel-pt(1)perf-kvm(1)perf-mem(1)perf-top(1)