1PERF-REPORT(1)                    perf Manual                   PERF-REPORT(1)
2
3
4

NAME

6       perf-report - Read perf.data (created by perf record) and display the
7       profile
8

SYNOPSIS

10       perf report [-i <file> | --input=file]
11

DESCRIPTION

13       This command displays the performance counter profile information
14       recorded via perf record.
15

OPTIONS

17       -i, --input=
18           Input file name. (default: perf.data unless stdin is a fifo)
19
20       -v, --verbose
21           Be more verbose. (show symbol address, etc)
22
23       -q, --quiet
24           Do not show any message. (Suppress -v)
25
26       -n, --show-nr-samples
27           Show the number of samples for each symbol
28
29       --show-cpu-utilization
30           Show sample percentage for different cpu modes.
31
32       -T, --threads
33           Show per-thread event counters. The input data file should be
34           recorded with -s option.
35
36       -c, --comms=
37           Only consider symbols in these comms. CSV that understands
38           file://filename entries. This option will affect the percentage of
39           the overhead column. See --percentage for more info.
40
41       --pid=
42           Only show events for given process ID (comma separated list).
43
44       --tid=
45           Only show events for given thread ID (comma separated list).
46
47       -d, --dsos=
48           Only consider symbols in these dsos. CSV that understands
49           file://filename entries. This option will affect the percentage of
50           the overhead column. See --percentage for more info.
51
52       -S, --symbols=
53           Only consider these symbols. CSV that understands file://filename
54           entries. This option will affect the percentage of the overhead
55           column. See --percentage for more info.
56
57       --symbol-filter=
58           Only show symbols that match (partially) with this filter.
59
60       -U, --hide-unresolved
61           Only display entries resolved to a symbol.
62
63       -s, --sort=
64           Sort histogram entries by given key(s) - multiple keys can be
65           specified in CSV format. Following sort keys are available: pid,
66           comm, dso, symbol, parent, cpu, socket, srcline, weight,
67           local_weight, cgroup_id.
68
69               Each key has following meaning:
70
71           ·   comm: command (name) of the task which can be read via
72               /proc/<pid>/comm
73
74           ·   pid: command and tid of the task
75
76           ·   dso: name of library or module executed at the time of sample
77
78           ·   dso_size: size of library or module executed at the time of
79               sample
80
81           ·   symbol: name of function executed at the time of sample
82
83           ·   symbol_size: size of function executed at the time of sample
84
85           ·   parent: name of function matched to the parent regex filter.
86               Unmatched entries are displayed as "[other]".
87
88           ·   cpu: cpu number the task ran at the time of sample
89
90           ·   socket: processor socket number the task ran at the time of
91               sample
92
93           ·   srcline: filename and line number executed at the time of
94               sample. The DWARF debugging info must be provided.
95
96           ·   srcfile: file name of the source file of the samples. Requires
97               dwarf information.
98
99           ·   weight: Event specific weight, e.g. memory latency or
100               transaction abort cost. This is the global weight.
101
102           ·   local_weight: Local weight version of the weight above.
103
104           ·   cgroup_id: ID derived from cgroup namespace device and inode
105               numbers.
106
107           ·   cgroup: cgroup pathname in the cgroupfs.
108
109           ·   transaction: Transaction abort flags.
110
111           ·   overhead: Overhead percentage of sample
112
113           ·   overhead_sys: Overhead percentage of sample running in system
114               mode
115
116           ·   overhead_us: Overhead percentage of sample running in user mode
117
118           ·   overhead_guest_sys: Overhead percentage of sample running in
119               system mode on guest machine
120
121           ·   overhead_guest_us: Overhead percentage of sample running in
122               user mode on guest machine
123
124           ·   sample: Number of sample
125
126           ·   period: Raw number of event count of sample
127
128           ·   time: Separate the samples by time stamp with the resolution
129               specified by --time-quantum (default 100ms). Specify with
130               overhead and before it.
131
132                   By default, comm, dso and symbol keys are used.
133                   (i.e. --sort comm,dso,symbol)
134
135                   If --branch-stack option is used, following sort keys are also
136                   available:
137
138           ·   dso_from: name of library or module branched from
139
140           ·   dso_to: name of library or module branched to
141
142           ·   symbol_from: name of function branched from
143
144           ·   symbol_to: name of function branched to
145
146           ·   srcline_from: source file and line branched from
147
148           ·   srcline_to: source file and line branched to
149
150           ·   mispredict: "N" for predicted branch, "Y" for mispredicted
151               branch
152
153           ·   in_tx: branch in TSX transaction
154
155           ·   abort: TSX transaction abort.
156
157           ·   cycles: Cycles in basic block
158
159                   And default sort keys are changed to comm, dso_from, symbol_from, dso_to
160                   and symbol_to, see '--branch-stack'.
161
162                   When the sort key symbol is specified, columns "IPC" and "IPC Coverage"
163                   are enabled automatically. Column "IPC" reports the average IPC per function
164                   and column "IPC coverage" reports the percentage of instructions with
165                   sampled IPC in this function. IPC means Instruction Per Cycle. If it's low,
166                   it indicates there may be a performance bottleneck when the function is
167                   executed, such as a memory access bottleneck. If a function has high overhead
168                   and low IPC, it's worth further analyzing it to optimize its performance.
169
170                   If the --mem-mode option is used, the following sort keys are also available
171                   (incompatible with --branch-stack):
172                   symbol_daddr, dso_daddr, locked, tlb, mem, snoop, dcacheline.
173
174           ·   symbol_daddr: name of data symbol being executed on at the time
175               of sample
176
177           ·   dso_daddr: name of library or module containing the data being
178               executed on at the time of the sample
179
180           ·   locked: whether the bus was locked at the time of the sample
181
182           ·   tlb: type of tlb access for the data at the time of the sample
183
184           ·   mem: type of memory access for the data at the time of the
185               sample
186
187           ·   snoop: type of snoop (if any) for the data at the time of the
188               sample
189
190           ·   dcacheline: the cacheline the data address is on at the time of
191               the sample
192
193           ·   phys_daddr: physical address of data being executed on at the
194               time of sample
195
196           ·   data_page_size: the data page size of data being executed on at
197               the time of sample
198
199                   And the default sort keys are changed to local_weight, mem, sym, dso,
200                   symbol_daddr, dso_daddr, snoop, tlb, locked, see '--mem-mode'.
201
202                   If the data file has tracepoint event(s), following (dynamic) sort keys
203                   are also available:
204                   trace, trace_fields, [<event>.]<field>[/raw]
205
206           ·   trace: pretty printed trace output in a single column
207
208           ·   trace_fields: fields in tracepoints in separate columns
209
210           ·   <field name>: optional event and field name for a specific
211               field
212
213                   The last form consists of event and field names.  If event name is
214                   omitted, it searches all events for matching field name.  The matched
215                   field will be shown only for the event has the field.  The event name
216                   supports substring match so user doesn't need to specify full subsystem
217                   and event name everytime.  For example, 'sched:sched_switch' event can
218                   be shortened to 'switch' as long as it's not ambiguous.  Also event can
219                   be specified by its index (starting from 1) preceded by the '%'.
220                   So '%1' is the first event, '%2' is the second, and so on.
221
222                   The field name can have '/raw' suffix which disables pretty printing
223                   and shows raw field value like hex numbers.  The --raw-trace option
224                   has the same effect for all dynamic sort keys.
225
226                   The default sort keys are changed to 'trace' if all events in the data
227                   file are tracepoint.
228
229       -F, --fields=
230           Specify output field - multiple keys can be specified in CSV
231           format. Following fields are available: overhead, overhead_sys,
232           overhead_us, overhead_children, sample and period. Also it can
233           contain any sort key(s).
234
235               By default, every sort keys not specified in -F will be appended
236               automatically.
237
238               If the keys starts with a prefix '+', then it will append the specified
239               field(s) to the default field order. For example: perf report -F +period,sample.
240
241       -p, --parent=<regex>
242           A regex filter to identify parent. The parent is a caller of this
243           function and searched through the callchain, thus it requires
244           callchain information recorded. The pattern is in the extended
245           regex format and defaults to "^sys_|^do_page_fault", see --sort
246           parent.
247
248       -x, --exclude-other
249           Only display entries with parent-match.
250
251       -w, --column-widths=<width[,width...]>
252           Force each column width to the provided list, for large terminal
253           readability. 0 means no limit (default behavior).
254
255       -t, --field-separator=
256           Use a special separator character and don’t pad with spaces,
257           replacing all occurrences of this separator in symbol names (and
258           other output) with a .  character, that thus it’s the only non
259           valid separator.
260
261       -D, --dump-raw-trace
262           Dump raw trace in ASCII.
263
264       -g,
265       --call-graph=<print_type,threshold[,print_limit],order,sort_key[,branch],value>
266           Display call chains using type, min percent threshold, print limit,
267           call order, sort key, optional branch and value. Note that ordering
268           is not fixed so any parameter can be given in an arbitrary order.
269           One exception is the print_limit which should be preceded by
270           threshold.
271
272               print_type can be either:
273               - flat: single column, linear exposure of call chains.
274               - graph: use a graph tree, displaying absolute overhead rates. (default)
275               - fractal: like graph, but displays relative rates. Each branch of
276                        the tree is considered as a new profiled object.
277               - folded: call chains are displayed in a line, separated by semicolons
278               - none: disable call chain display.
279
280               threshold is a percentage value which specifies a minimum percent to be
281               included in the output call graph.  Default is 0.5 (%).
282
283               print_limit is only applied when stdio interface is used.  It's to limit
284               number of call graph entries in a single hist entry.  Note that it needs
285               to be given after threshold (but not necessarily consecutive).
286               Default is 0 (unlimited).
287
288               order can be either:
289               - callee: callee based call graph.
290               - caller: inverted caller based call graph.
291               Default is 'caller' when --children is used, otherwise 'callee'.
292
293               sort_key can be:
294               - function: compare on functions (default)
295               - address: compare on individual code addresses
296               - srcline: compare on source filename and line number
297
298               branch can be:
299               - branch: include last branch information in callgraph when available.
300                         Usually more convenient to use --branch-history for this.
301
302               value can be:
303               - percent: display overhead percent (default)
304               - period: display event period
305               - count: display event count
306
307       --children
308           Accumulate callchain of children to parent entry so that then can
309           show up in the output. The output will have a new "Children" column
310           and will be sorted on the data. It requires callchains are
311           recorded. See the ‘overhead calculation’ section for more details.
312           Enabled by default, disable with --no-children.
313
314       --max-stack
315           Set the stack depth limit when parsing the callchain, anything
316           beyond the specified depth will be ignored. This is a trade-off
317           between information loss and faster processing especially for
318           workloads that can have a very long callchain stack. Note that when
319           using the --itrace option the synthesized callchain size will
320           override this value if the synthesized callchain size is bigger.
321
322               Default: 127
323
324       -G, --inverted
325           alias for inverted caller based call graph.
326
327       --ignore-callees=<regex>
328           Ignore callees of the function(s) matching the given regex. This
329           has the effect of collecting the callers of each such function into
330           one place in the call-graph tree.
331
332       --pretty=<key>
333           Pretty printing style. key: normal, raw
334
335       --stdio
336           Use the stdio interface.
337
338       --stdio-color
339           always, never or auto, allowing configuring color output via the
340           command line, in addition to via "color.ui" .perfconfig. Use
341           --stdio-color always to generate color even when redirecting to a
342           pipe or file. Using just --stdio-color is equivalent to using
343           always.
344
345       --tui
346           Use the TUI interface, that is integrated with annotate and allows
347           zooming into DSOs or threads, among other features. Use of --tui
348           requires a tty, if one is not present, as when piping to other
349           commands, the stdio interface is used.
350
351       --gtk
352           Use the GTK2 interface.
353
354       -k, --vmlinux=<file>
355           vmlinux pathname
356
357       --ignore-vmlinux
358           Ignore vmlinux files.
359
360       --kallsyms=<file>
361           kallsyms pathname
362
363       -m, --modules
364           Load module symbols. WARNING: This should only be used with -k and
365           a LIVE kernel.
366
367       -f, --force
368           Don’t do ownership validation.
369
370       --symfs=<directory>
371           Look for files with symbols relative to this directory.
372
373       -C, --cpu
374           Only report samples for the list of CPUs provided. Multiple CPUs
375           can be provided as a comma-separated list with no space: 0,1.
376           Ranges of CPUs are specified with -: 0-2. Default is to report
377           samples on all CPUs.
378
379       -M, --disassembler-style=
380           Set disassembler style for objdump.
381
382       --source
383           Interleave source code with assembly code. Enabled by default,
384           disable with --no-source.
385
386       --asm-raw
387           Show raw instruction encoding of assembly instructions.
388
389       --show-total-period
390           Show a column with the sum of periods.
391
392       -I, --show-info
393           Display extended information about the perf.data file. This adds
394           information which may be very large and thus may clutter the
395           display. It currently includes: cpu and numa topology of the host
396           system.
397
398       -b, --branch-stack
399           Use the addresses of sampled taken branches instead of the
400           instruction address to build the histograms. To generate meaningful
401           output, the perf.data file must have been obtained using perf
402           record -b or perf record --branch-filter xxx where xxx is a branch
403           filter option. perf report is able to auto-detect whether a
404           perf.data file contains branch stacks and it will automatically
405           switch to the branch view mode, unless --no-branch-stack is used.
406
407       --branch-history
408           Add the addresses of sampled taken branches to the callstack. This
409           allows to examine the path the program took to each sample. The
410           data collection must have used -b (or -j) and -g.
411
412       --objdump=<path>
413           Path to objdump binary.
414
415       --prefix=PREFIX, --prefix-strip=N
416           Remove first N entries from source file path names in executables
417           and add PREFIX. This allows to display source code compiled on
418           systems with different file system layout.
419
420       --group
421           Show event group information together. It forces group output also
422           if there are no groups defined in data file.
423
424       --group-sort-idx
425           Sort the output by the event at the index n in group. If n is
426           invalid, sort by the first event. It can support multiple groups
427           with different amount of events. WARNING: This should be used on
428           grouped events.
429
430       --demangle
431           Demangle symbol names to human readable form. It’s enabled by
432           default, disable with --no-demangle.
433
434       --demangle-kernel
435           Demangle kernel symbol names to human readable form (for C++
436           kernels).
437
438       --mem-mode
439           Use the data addresses of samples in addition to instruction
440           addresses to build the histograms. To generate meaningful output,
441           the perf.data file must have been obtained using perf record -d -W
442           and using a special event -e cpu/mem-loads/p or -e
443           cpu/mem-stores/p. See perf mem for simpler access.
444
445       --percent-limit
446           Do not show entries which have an overhead under that percent.
447           (Default: 0). Note that this option also sets the percent limit
448           (threshold) of callchains. However the default value of callchain
449           threshold is different than the default value of hist entries.
450           Please see the --call-graph option for details.
451
452       --percentage
453           Determine how to display the overhead percentage of filtered
454           entries. Filters can be applied by --comms, --dsos and/or --symbols
455           options and Zoom operations on the TUI (thread, dso, etc).
456
457               "relative" means it's relative to filtered entries only so that the
458               sum of shown entries will be always 100%.  "absolute" means it retains
459               the original value before and after the filter is applied.
460
461       --header
462           Show header information in the perf.data file. This includes
463           various information like hostname, OS and perf version, cpu/mem
464           info, perf command line, event list and so on. Currently only
465           --stdio output supports this feature.
466
467       --header-only
468           Show only perf.data header (forces --stdio).
469
470       --time
471           Only analyze samples within given time window: <start>,<stop>.
472           Times have the format seconds.nanoseconds. If start is not given
473           (i.e. time string is ,x.y) then analysis starts at the beginning of
474           the file. If stop time is not given (i.e. time string is x.y,) then
475           analysis goes to end of file. Multiple ranges can be separated by
476           spaces, which requires the argument to be quoted e.g. --time
477           "1234.567,1234.789 1235,"
478
479               Also support time percent with multiple time ranges. Time string is
480               'a%/n,b%/m,...' or 'a%-b%,c%-%d,...'.
481
482               For example:
483               Select the second 10% time slice:
484
485               perf report --time 10%/2
486
487               Select from 0% to 10% time slice:
488
489               perf report --time 0%-10%
490
491               Select the first and second 10% time slices:
492
493               perf report --time 10%/1,10%/2
494
495               Select from 0% to 10% and 30% to 40% slices:
496
497               perf report --time 0%-10%,30%-40%
498
499       --switch-on EVENT_NAME
500           Only consider events after this event is found.
501
502               This may be interesting to measure a workload only after some initialization
503               phase is over, i.e. insert a perf probe at that point and then using this
504               option with that probe.
505
506       --switch-off EVENT_NAME
507           Stop considering events after this event is found.
508
509       --show-on-off-events
510           Show the --switch-on/off events too. This has no effect in perf
511           report now but probably we’ll make the default not to show the
512           switch-on/off events on the --group mode and if there is only one
513           event besides the off/on ones, go straight to the histogram
514           browser, just like perf report with no events explicitely specified
515           does.
516
517       --itrace
518           Options for decoding instruction tracing data. The options are:
519
520               i       synthesize instructions events
521               b       synthesize branches events (branch misses for Arm SPE)
522               c       synthesize branches events (calls only)
523               r       synthesize branches events (returns only)
524               x       synthesize transactions events
525               w       synthesize ptwrite events
526               p       synthesize power events
527               o       synthesize other events recorded due to the use
528                       of aux-output (refer to perf record)
529               e       synthesize error events
530               d       create a debug log
531               f       synthesize first level cache events
532               m       synthesize last level cache events
533               M       synthesize memory events
534               t       synthesize TLB events
535               a       synthesize remote access events
536               g       synthesize a call chain (use with i or x)
537               G       synthesize a call chain on existing event records
538               l       synthesize last branch entries (use with i or x)
539               L       synthesize last branch entries on existing event records
540               s       skip initial number of events
541               q       quicker (less detailed) decoding
542
543               The default is all events i.e. the same as --itrace=ibxwpe,
544               except for perf script where it is --itrace=ce
545
546               In addition, the period (default 100000, except for perf script where it is 1)
547               for instructions events can be specified in units of:
548
549               i       instructions
550               t       ticks
551               ms      milliseconds
552               us      microseconds
553               ns      nanoseconds (default)
554
555               Also the call chain size (default 16, max. 1024) for instructions or
556               transactions events can be specified.
557
558               Also the number of last branch entries (default 64, max. 1024) for
559               instructions or transactions events can be specified.
560
561               Similar to options g and l, size may also be specified for options G and L.
562               On x86, note that G and L work poorly when data has been recorded with
563               large PEBS. Refer linkperf:perf-intel-pt[1] man page for details.
564
565               It is also possible to skip events generated (instructions, branches, transactions,
566               ptwrite, power) at the beginning. This is useful to ignore initialization code.
567
568               --itrace=i0nss1000000
569
570               skips the first million instructions.
571
572               The 'e' option may be followed by flags which affect what errors will or
573               will not be reported. Each flag must be preceded by either '+' or '-'.
574               The flags are:
575                       o       overflow
576                       l       trace data lost
577
578               If supported, the 'd' option may be followed by flags which affect what
579               debug messages will or will not be logged. Each flag must be preceded
580               by either '+' or '-'. The flags are:
581                       a       all perf events
582
583               If supported, the 'q' option may be repeated to increase the effect.
584
585               To disable decoding entirely, use --no-itrace.
586
587       --full-source-path
588           Show the full path for source files for srcline output.
589
590       --show-ref-call-graph
591           When multiple events are sampled, it may not be needed to collect
592           callgraphs for all of them. The sample sites are usually nearby,
593           and it’s enough to collect the callgraphs on a reference event. So
594           user can use "call-graph=no" event modifier to disable callgraph
595           for other events to reduce the overhead. However, perf report
596           cannot show callgraphs for the event which disable the callgraph.
597           This option extends the perf report to show reference callgraphs,
598           which collected by reference event, in no callgraph event.
599
600       --stitch-lbr
601           Show callgraph with stitched LBRs, which may have more complete
602           callgraph. The perf.data file must have been obtained using perf
603           record --call-graph lbr. Disabled by default. In common cases with
604           call stack overflows, it can recreate better call stacks than the
605           default lbr call stack output. But this approach is not full proof.
606           There can be cases where it creates incorrect call stacks from
607           incorrect matches. The known limitations include exception handing
608           such as setjmp/longjmp will have calls/returns not match.
609
610       --socket-filter
611           Only report the samples on the processor socket that match with
612           this filter
613
614       --samples=N
615           Save N individual samples for each histogram entry to show context
616           in perf report tui browser.
617
618       --raw-trace
619           When displaying traceevent output, do not use print fmt or plugins.
620
621       --hierarchy
622           Enable hierarchical output.
623
624       --inline
625           If a callgraph address belongs to an inlined function, the inline
626           stack will be printed. Each entry is function name or file/line.
627           Enabled by default, disable with --no-inline.
628
629       --mmaps
630           Show --tasks output plus mmap information in a format similar to
631           /proc/<PID>/maps.
632
633               Please note that not all mmaps are stored, options affecting which ones
634               are include 'perf record --data', for instance.
635
636       --ns
637           Show time stamps in nanoseconds.
638
639       --stats
640           Display overall events statistics without any further processing.
641           (like the one at the end of the perf report -D command)
642
643       --tasks
644           Display monitored tasks stored in perf data. Displaying
645           pid/tid/ppid plus the command string aligned to distinguish parent
646           and child tasks.
647
648       --percent-type
649           Set annotation percent type from following choices: global-period,
650           local-period, global-hits, local-hits
651
652               The local/global keywords set if the percentage is computed
653               in the scope of the function (local) or the whole data (global).
654               The period/hits keywords set the base the percentage is computed
655               on - the samples period or the number of samples (hits).
656
657       --time-quantum
658           Configure time quantum for time sort key. Default 100ms. Accepts s,
659           us, ms, ns units.
660
661       --total-cycles
662           When --total-cycles is specified, it supports sorting for all
663           blocks by Sampled Cycles%. This is useful to concentrate on the
664           globally hottest blocks. In output, there are some new columns:
665
666               'Sampled Cycles%' - block sampled cycles aggregation / total sampled cycles
667               'Sampled Cycles'  - block sampled cycles aggregation
668               'Avg Cycles%'     - block average sampled cycles / sum of total block average
669                                   sampled cycles
670               'Avg Cycles'      - block average sampled cycles
671

OVERHEAD CALCULATION

673       The overhead can be shown in two columns as Children and Self when perf
674       collects callchains. The self overhead is simply calculated by adding
675       all period values of the entry - usually a function (symbol). This is
676       the value that perf shows traditionally and sum of all the self
677       overhead values should be 100%.
678
679       The children overhead is calculated by adding all period values of the
680       child functions so that it can show the total overhead of the higher
681       level functions even if they don’t directly execute much. Children here
682       means functions that are called from another (parent) function.
683
684       It might be confusing that the sum of all the children overhead values
685       exceeds 100% since each of them is already an accumulation of self
686       overhead of its child functions. But with this enabled, users can find
687       which function has the most overhead even if samples are spread over
688       the children.
689
690       Consider the following example; there are three functions like below.
691
692
693           .ft C
694           void foo(void) {
695               /* do something */
696           }
697
698           void bar(void) {
699               /* do something */
700               foo();
701           }
702
703           int main(void) {
704               bar()
705               return 0;
706           }
707           .ft
708
709
710       In this case foo is a child of bar, and bar is an immediate child of
711       main so foo also is a child of main. In other words, main is a parent
712       of foo and bar, and bar is a parent of foo.
713
714       Suppose all samples are recorded in foo and bar only. When it’s
715       recorded with callchains the output will show something like below in
716       the usual (self-overhead-only) output of perf report:
717
718
719           .ft C
720           Overhead  Symbol
721           ........  .....................
722             60.00%  foo
723                     |
724                     --- foo
725                         bar
726                         main
727                         __libc_start_main
728
729             40.00%  bar
730                     |
731                     --- bar
732                         main
733                         __libc_start_main
734           .ft
735
736
737       When the --children option is enabled, the self overhead values of
738       child functions (i.e. foo and bar) are added to the parents to
739       calculate the children overhead. In this case the report could be
740       displayed as:
741
742
743           .ft C
744           Children      Self  Symbol
745           ........  ........  ....................
746            100.00%     0.00%  __libc_start_main
747                     |
748                     --- __libc_start_main
749
750            100.00%     0.00%  main
751                     |
752                     --- main
753                         __libc_start_main
754
755            100.00%    40.00%  bar
756                     |
757                     --- bar
758                         main
759                         __libc_start_main
760
761             60.00%    60.00%  foo
762                     |
763                     --- foo
764                         bar
765                         main
766                         __libc_start_main
767           .ft
768
769
770       In the above output, the self overhead of foo (60%) was add to the
771       children overhead of bar, main and __libc_start_main. Likewise, the
772       self overhead of bar (40%) was added to the children overhead of main
773       and \_\_libc_start_main.
774
775       So \_\_libc_start_main and main are shown first since they have same
776       (100%) children overhead (even though they have zero self overhead) and
777       they are the parents of foo and bar.
778
779       Since v3.16 the children overhead is shown by default and the output is
780       sorted by its values. The children overhead is disabled by specifying
781       --no-children option on the command line or by adding report.children =
782       false or top.children = false in the perf config file.
783

SEE ALSO

785       perf-stat(1), perf-annotate(1), perf-record(1), perf-intel-pt(1)
786
787
788
789perf                              03/30/2021                    PERF-REPORT(1)
Impressum