NAME | SYNOPSIS | DESCRIPTION | OPTIONS | OVERHEAD CALCULATION | SEE ALSO | COLOPHON

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

NAME         top

       perf-report - Read perf.data (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: perf.data 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-cpu-utilization
           Show sample percentage for different cpu modes.

       -T, --threads
           Show per-thread event counters. The input data file should be
           recorded with -s option.

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

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

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

       -d, --dsos=
           Only consider symbols in these dsos. CSV that understands
           file://filename entries. This option will affect the percentage
           of the overhead 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.

       --symbol-filter=
           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
               /proc/<pid>/comm

           ·   pid: command and tid of the task

           ·   dso: name of library or module executed at the time of sample

           ·   symbol: name of function executed at the time of sample

           ·   symbol_size: size of function executed at the time of sample

           ·   parent: name of function matched to the parent regex filter.
               Unmatched entries are displayed as "[other]".

           ·   cpu: cpu number the task ran at the time of sample

           ·   socket: processor socket number the task ran at the time of
               sample

           ·   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 same. 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.

           ·   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

                   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
                   available:

           ·   dso_from: name of library or module branched from

           ·   dso_to: name of library or module branched to

           ·   symbol_from: name of function branched from

           ·   symbol_to: name of function branched to

           ·   srcline_from: source file and line branched from

           ·   srcline_to: source file and line branched to

           ·   mispredict: "N" for predicted branch, "Y" for mispredicted
               branch

           ·   in_tx: branch in TSX transaction

           ·   abort: TSX transaction abort.

           ·   cycles: Cycles in basic block

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

                   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
               sample

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

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

           ·   dcacheline: the cacheline the data address is on at the time
               of the sample

           ·   phys_daddr: physical address of data being executed on at the
               time of sample

                   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
               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
               automatically.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

               Default: 127

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

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

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

       --stdio
           Use the stdio interface.

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

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

       --gtk
           Use the GTK2 interface.

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

       --kallsyms=<file>
           kallsyms pathname

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

       -f, --force
           Don’t do ownership validation.

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

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

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

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

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

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

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

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

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

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

       --group
           Show event group information together.

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

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

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

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

       --percentage
           Determine how to display the 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.

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

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

       --time
           Only analyze samples within given time window: <start>,<stop>.
           Times have the format seconds.microseconds. 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.

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

               i       synthesize instructions events
               b       synthesize branches events
               c       synthesize branches events (calls only)
               r       synthesize branches events (returns only)
               x       synthesize transactions events
               w       synthesize ptwrite events
               p       synthesize power events
               e       synthesize error events
               d       create a debug log
               g       synthesize a call chain (use with i or x)
               l       synthesize last branch entries (use with i or x)
               s       skip initial number of events

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

               In addition, the period (default 100000) 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.

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

               --itrace=i0nss1000000

               skips the first million instructions.

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

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

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

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

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

       --hierarchy
           Enable hierarchical output.

       --inline
           If a callgraph address belongs to an inlined function, the inline
           stack will be printed. Each entry is function name or file/line.

OVERHEAD CALCULATION         top

       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)
       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 below.

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

           void bar(void) {
               /* do something */
               foo();
           }

           int main(void) {
               bar()
               return 0;
           }
           .ft

       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
                         bar
                         main
                         __libc_start_main

             40.00%  bar
                     |
                     --- bar
                         main
                         __libc_start_main
           .ft

       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
                         __libc_start_main

            100.00%    40.00%  bar
                     |
                     --- bar
                         main
                         __libc_start_main

             60.00%    60.00%  foo
                     |
                     --- foo
                         bar
                         main
                         __libc_start_main
           .ft

       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)

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 ⟨https://perf.wiki.kernel.org/index.php/Main_Page⟩.  If
       you have a bug report for this manual page, send it to
       linux-kernel@vger.kernel.org.  This page was obtained from the
       project's upstream Git repository 
       ⟨http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git⟩ on
       2017-09-15.  If you discover any rendering problems in this HTML ver‐
       sion 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 man‐
       ual page), send a mail to man-pages@man7.org

perf                             09/14/2017                   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-kvm(1)perf-mem(1)perf-top(1)