trace-cmd-report(1) — Linux manual page


TRACE-CMD-REPORT(1)                                  TRACE-CMD-REPORT(1)

NAME         top

       trace-cmd-report - show in ASCII a trace created by trace-cmd

SYNOPSIS         top

       trace-cmd report [OPTIONS] [input-file]

DESCRIPTION         top

       The trace-cmd(1) report command will output a human readable
       report of a trace created by trace-cmd record.

OPTIONS         top

       -i input-file
           By default, trace-cmd report will read the file trace.dat.
           But the -i option open up the given input-file instead. Note,
           the input file may also be specified as the last item on the
           command line.

           This outputs the endianess of the file. trace-cmd report is
           smart enough to be able to read big endian files on little
           endian machines, and vise versa.

           This outputs the list of all functions that have been mapped
           in the trace.dat file. Note, this list may contain functions
           that may not appear in the trace, as it is the list of
           mappings to translate function addresses into function names.

           This outputs the list of "trace_printk()" data. The raw trace
           data points to static pointers in the kernel. This must be
           stored in the trace.dat file.

           This lists the possible events in the file (but this list is
           not necessarily the list of events in the file).

           This will list the event formats that are stored in the
           trace.dat file.

       --event regex
           This will print events that match the given regex. If a colon
           is specified, then the characters before the colon will be
           used to match the system and the characters after the colon
           will match the event.

               trace-cmd report --event sys:read

               The above will only match events where the system name contains "sys"
               and the event name contains "read".

               trace-cmd report --event read

               The above will match all events that contain "read" in its name. Also it
               may list all events of a system that contains "read" as well.

           This will parse the event format strings that are stored in
           the trace.dat file and return whether the formats can be
           parsed correctly. It will load plugins unless -N is

           Print the full timestamp. The timestamps in the data file are
           usually recorded to the nanosecond. But the default display
           of the timestamp is only to the microsecond. To see the full
           timestamp, add the -t option.

       -F filter
           Add a filter to limit what events are displayed. The format
           of the filter is:

               <events> ':' <filter>
               <events> = SYSTEM'/'EVENT  | SYSTEM | EVENT | <events> ',' <events>
               <filter> = EVENT_FIELD <op> <value> | <filter> '&&' <filter> |
                          <filter> '||' <filter> | '(' <filter> ')' | '!' <filter>
               <op> = '==' | '!=' | '>=' | '<=' | '>' | '<' | '&' | '|' | '^' |
                      '+' | '-' | '*' | '/' | '%'
               <value> = NUM | STRING | EVENT_FIELD

           SYSTEM is the name of the system to filter on. If the EVENT is left out,
           then it applies to all events under the SYSTEM. If only one string is used
           without the '/' to deliminate between SYSTEM and EVENT, then the filter
           will be applied to all systems and events that match the given string.

           Whitespace is ignored, such that "sched:next_pid==123" is equivalent to
           "sched : next_pid == 123".

           STRING is defined with single or double quotes (single quote must end with
           single quote, and double with double). Whitespace within quotes are not

           The representation of a SYSTEM or EVENT may also be a regular expression
           as defined by 'regcomp(3)'.

           The EVENT_FIELD is the name of the field of an event that is being
           filtered. If the event does not contain the EVENT_FIELD, that part of the
           equation will be considered false.

               -F 'sched : bogus == 1 || common_pid == 2'

           The "bogus == 1" will always evaluate to FALSE because no event has a
           field called "bogus", but the "common_pid == 2" will still be evaluated
           since all events have the field "common_pid". Any "sched" event that was
           traced by the process with the PID of 2 will be shown.

           Note, the EVENT_FIELD is the field name as shown by an events format
           (as displayed with *--events*), and not what is found in the output.
           If the output shows "ID:foo" but the field that "foo" belongs to was
           called "name" in the event format, then "name" must be used in the filter.
           The same is true about values. If the value that is displayed is converted
           by to a string symbol, the filter checks the original value and not the
           value displayed. For example, to filter on all tasks that were in the
           running state at a context switch:

               -F 'sched/sched_switch : prev_state==0'

           Although the output displays 'R', having 'prev_stat=="R"' will not work.

           Note: You can also specify 'COMM' as an EVENT_FIELD. This will use the
           task name (or comm) of the record to compare. For example, to filter out
           all of the "trace-cmd" tasks:

               -F '.*:COMM != "trace-cmd"'

           Do not print events where the HARDIRQ latency flag is set.
           This will filter out most events that are from interrupt
           context. Note, it may not filter out function traced
           functions that are in interrupt context but were called
           before the kernel "in interrupt" flag was set.

           Do not print events where the SOFTIRQ latency flag is set.
           This will filter out most events that are from soft interrupt

           This causes the following filters of -F to filter out the
           matching events.

               -v -F 'sched/sched_switch : prev_state == 0'

           Will not display any sched_switch events that have a prev_state of 0.
           Removing the *-v* will only print out those events.

           Test the filters of -F. After processing a filter string, the
           resulting filter will be displayed for each event. This is
           useful for using a filter for more than one event where a
           field may not exist in all events. Also it can be used to
           make sure there are no misspelled event field names, as they
           will simply be ignored.  -T is ignored if -F is not

           Show the plugins that are loaded.

           This will not load system wide plugins. It loads "local
           only". That is what it finds in the ~/.trace-cmd/plugins

           This will not load any plugins.

       -n event-re
           This will cause all events that match the option to ignore
           any registered handler (by the plugins) to print the event.
           The normal event will be printed instead. The event-re is a
           regular expression as defined by regcomp(3).

           With the --profile option, "trace-cmd report" will process
           all the events first, and then output a format showing where
           tasks have spent their time in the kernel, as well as where
           they are blocked the most, and where wake up latencies are.

               See trace-cmd-profile(1) for more details and examples.

           Set interrupt (soft and hard) events as global (associated to
           CPU instead of tasks). Only works for --profile.

       -H event-hooks
           Add custom event matching to connect any two events together.

               See trace-cmd-profile(1) for format.

           This will show the events in "raw" format. That is, it will
           ignore the event’s print formatting and just print the
           contents of each field.

       -r event-re
           This will cause all events that match the option to print its
           raw fields. The event-re is a regular expression as defined
           by regcomp(3).

           This adds a "latency output" format. Information about
           interrupts being disabled, soft irq being disabled, the
           "need_resched" flag being set, preempt count, and big kernel
           lock are all being recorded with every event. But the default
           display does not show this information. This option will set
           display this information with 6 characters. When one of the
           fields is zero or N/A a '.\' is shown.

                 <idle>-0       0d.h1. 106467.859747: function:             ktime_get <-- tick_check_idle

           The 0d.h1. denotes this information. The first character is never a '.'
           and represents what CPU the trace was recorded on (CPU 0). The 'd' denotes
           that interrupts were disabled. The 'h' means that this was called inside
           an interrupt handler. The '1' is the preemption disabled (preempt_count)
           was set to one.  The two '.'s are "need_resched" flag and kernel lock
           counter.  If the "need_resched" flag is set, then that character would be a

           If both the sched_switch and sched_wakeup events are enabled,
           then this option will report the latency between the time the
           task was first woken, and the time it was scheduled in.

           Quiet non critical warnings.

           Pass options to the trace-cmd plugins that are loaded.

               -O plugin:var=value

               The 'plugin:' and '=value' are optional. Value may be left off for options
               that are boolean. If the 'plugin:' is left off, then any variable that matches
               in all plugins will be set.

               Example:  -O fgraph:tailprint

       --cpu <cpu list>
           List of CPUs, separated by "," or ":", used for filtering the
           events. A range of CPUs can be specified using "cpuX-cpuY"
           notation, where all CPUs in the range between cpuX and cpuY
           will be included in the list. The order of CPUs in the list
           must be from lower to greater.

               Example:  "--cpu 0,3" - show events from CPUs 0 and 3
                         "--cpu 2-4" - show events from CPUs 2, 3 and 4

           If the trace.dat file recorded the final stats (outputed at
           the end of record) the --stat option can be used to retrieve

           If the trace.dat file recorded uname during the run, this
           will retrieve that information.

           If the trace.dat file recorded the version of the executable
           used to create it, report that version.

       --ts-offset offset
           Add (or subtract if negative) an offset for all timestamps of
           the previous data file specified with -i. This is useful to
           merge sort multiple trace.dat files where the difference in
           the timestamp is known. For example if a trace is done on a
           virtual guest, and another trace is done on the host. If the
           host timestamp is 1000 units ahead of the guest, the
           following can be done:

               trace-cmd report -i host.dat --ts-offset -1000 -i guest.dat

               This will subtract 1000 timestamp units from all the host events as it merges
               with the guest.dat events. Note, the units is for the raw units recorded in
               the trace. If the units are nanoseconds, the addition (or subtraction) from
               the offset will be nanoseconds even if the displayed units are microseconds.

       --ts2secs HZ
           Convert the current clock source into a second (nanosecond
           resolution) output. When using clocks like x86-tsc, if the
           frequency is known, by passing in the clock frequency, this
           will convert the time to seconds.

               This option affects any trace.dat file given with *-i* proceeding it.
               If this option comes before any *-i* option, then that value becomes
               the default conversion for all other trace.dat files. If another
               --ts2secs option appears after a *-i* trace.dat file, than that option
               will override the default value.

               Example: On a 3.4 GHz machine

               trace-cmd record -p function -C x86-tsc

               trace-cmd report --ts2ns 3400000000

               The report will convert the cycles timestamps into a readable second
               display. The default display resolution is microseconds, unless *-t*
               is used.

               The value of --ts-offset must still be in the raw timestamp units, even
               with this option. The offset will be converted as well.

           Show the time differences between events. The difference will
           appear in parenthesis just after the timestamp.

           Make sure no timestamp goes backwards, and if it does, print
           out a warning message of the fact.

EXAMPLES         top

       Using a trace.dat file that was created with:

               # trace-cmd record -p function -e all sleep 5

       The default report shows:

            # trace-cmd report
                  trace-cmd-16129 [002] 158126.498411: function: __mutex_unlock_slowpath <-- mutex_unlock
                  trace-cmd-16131 [000] 158126.498411: kmem_cache_alloc: call_site=811223c5 ptr=0xffff88003ecf2b40 bytes_req=272 bytes_alloc=320 gfp_flags=GFP_KERNEL|GFP_ZERO
                  trace-cmd-16130 [003] 158126.498411: function:             do_splice_to <-- sys_splice
                      sleep-16133 [001] 158126.498412: function: inotify_inode_queue_event <-- vfs_write
                  trace-cmd-16129 [002] 158126.498420: lock_release: 0xffff88003f1fa4f8 &sb->s_type->i_mutex_key
                  trace-cmd-16131 [000] 158126.498421: function: security_file_alloc <-- get_empty_filp
                      sleep-16133 [001] 158126.498422: function: __fsnotify_parent <-- vfs_write
                  trace-cmd-16130 [003] 158126.498422: function: rw_verify_area <-- do_splice_to
                  trace-cmd-16131 [000] 158126.498424: function: cap_file_alloc_security <-- security_file_alloc
                  trace-cmd-16129 [002] 158126.498425: function: syscall_trace_leave <-- int_check_syscall_exit_work
                      sleep-16133 [001] 158126.498426: function: inotify_dentry_parent_queue_event <-- vfs_write
                  trace-cmd-16130 [003] 158126.498426: function: security_file_permission <-- rw_verify_area
                  trace-cmd-16129 [002] 158126.498428: function: audit_syscall_exit <-- syscall_trace_leave

       To see everything but the function traces:

            # trace-cmd report -v -F 'function'
                  trace-cmd-16131 [000] 158126.498411: kmem_cache_alloc: call_site=811223c5 ptr=0xffff88003ecf2b40 bytes_req=272 bytes_alloc=320 gfp_flags=GFP_KERNEL|GFP_ZERO
                  trace-cmd-16129 [002] 158126.498420: lock_release: 0xffff88003f1fa4f8 &sb->s_type->i_mutex_key
                  trace-cmd-16130 [003] 158126.498436: lock_acquire: 0xffffffff8166bf78 read all_cpu_access_lock
                  trace-cmd-16131 [000] 158126.498438: lock_acquire: 0xffff88003df5b520 read &fs->lock
                  trace-cmd-16129 [002] 158126.498446: kfree: call_site=810a7abb ptr=0x0
                  trace-cmd-16130 [003] 158126.498448: lock_acquire: 0xffff880002250a80 &per_cpu(cpu_access_lock, cpu)
                  trace-cmd-16129 [002] 158126.498450: sys_exit_splice:      0xfffffff5
                  trace-cmd-16131 [000] 158126.498454: lock_release: 0xffff88003df5b520 &fs->lock
                      sleep-16133 [001] 158126.498456: kfree: call_site=810a7abb ptr=0x0
                      sleep-16133 [001] 158126.498460: sys_exit_write:       0x1
                  trace-cmd-16130 [003] 158126.498462: kmalloc: call_site=810bf95b ptr=0xffff88003dedc040 bytes_req=24 bytes_alloc=32 gfp_flags=GFP_KERNEL|GFP_ZERO

       To see only the kmalloc calls that were greater than 1000 bytes:

            #trace-cmd report -F 'kmalloc: bytes_req > 1000'
                     <idle>-0     [000] 158128.126641: kmalloc: call_site=81330635 ptr=0xffff88003c2fd000 bytes_req=2096 bytes_alloc=4096 gfp_flags=GFP_ATOMIC

       To see wakeups and sched switches that left the previous task in
       the running state:

            # trace-cmd report -F 'sched: prev_state == 0 || (success == 1)'
                  trace-cmd-16132 [002] 158126.499951: sched_wakeup: comm=trace-cmd pid=16129 prio=120 success=1 target_cpu=002
                  trace-cmd-16132 [002] 158126.500401: sched_switch: prev_comm=trace-cmd prev_pid=16132 prev_prio=120 prev_state=R ==> next_comm=trace-cmd next_pid=16129 next_prio=120
                     <idle>-0     [003] 158126.500585: sched_wakeup: comm=trace-cmd pid=16130 prio=120 success=1 target_cpu=003
                     <idle>-0     [003] 158126.501241: sched_switch: prev_comm=swapper prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=trace-cmd next_pid=16130 next_prio=120
                  trace-cmd-16132 [000] 158126.502475: sched_wakeup: comm=trace-cmd pid=16131 prio=120 success=1 target_cpu=000
                  trace-cmd-16131 [002] 158126.506516: sched_wakeup: comm=trace-cmd pid=16129 prio=120 success=1 target_cpu=002
                     <idle>-0     [003] 158126.550110: sched_switch: prev_comm=swapper prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=trace-cmd next_pid=16130 next_prio=120
                  trace-cmd-16131 [003] 158126.570243: sched_wakeup: comm=trace-cmd pid=16129 prio=120 success=1 target_cpu=003
                  trace-cmd-16130 [002] 158126.618202: sched_switch: prev_comm=trace-cmd prev_pid=16130 prev_prio=120 prev_state=R ==> next_comm=yum-updatesd next_pid=3088 next_prio=1 20
                  trace-cmd-16129 [003] 158126.622379: sched_wakeup: comm=trace-cmd pid=16131 prio=120 success=1 target_cpu=003
                  trace-cmd-16129 [000] 158126.649287: sched_wakeup: comm=trace-cmd pid=16131 prio=120 success=1 target_cpu=000

       The above needs a little explanation. The filter specifies the
       "sched" subsystem, which includes both sched_switch and
       sched_wakeup events. Any event that does not have the format
       field "prev_state" or "success", will evaluate those expressions
       as FALSE, and will not produce a match. Using "||" will have the
       "prev_state" test happen for the "sched_switch" event and the
       "success" test happen for the "sched_wakeup" event.

             # trace-cmd report -w -F 'sched_switch, sched_wakeup.*'
                  trace-cmd-16130 [003] 158131.580616: sched_wakeup: comm=trace-cmd pid=16131 prio=120 success=1 target_cpu=003
                  trace-cmd-16129 [000] 158131.581502: sched_switch: prev_comm=trace-cmd prev_pid=16129 prev_prio=120 prev_state=S ==> next_comm=trace-cmd next_pid=16131 next_prio=120 Latency: 885.901 usecs
                  trace-cmd-16131 [000] 158131.582414: sched_wakeup: comm=trace-cmd pid=16129 prio=120 success=1 target_cpu=000
                  trace-cmd-16132 [001] 158131.583219: sched_switch: prev_comm=trace-cmd prev_pid=16132 prev_prio=120 prev_state=S ==> next_comm=trace-cmd next_pid=16129 next_prio=120 Latency: 804.809 usecs
                      sleep-16133 [002] 158131.584121: sched_wakeup: comm=trace-cmd pid=16120 prio=120 success=1 target_cpu=002
                  trace-cmd-16129 [001] 158131.584128: sched_wakeup: comm=trace-cmd pid=16132 prio=120 success=1 target_cpu=001
                      sleep-16133 [002] 158131.584275: sched_switch: prev_comm=sleep prev_pid=16133 prev_prio=120 prev_state=R ==> next_comm=trace-cmd next_pid=16120 next_prio=120 Latency: 153.915 usecs
                  trace-cmd-16130 [003] 158131.585284: sched_switch: prev_comm=trace-cmd prev_pid=16130 prev_prio=120 prev_state=S ==> next_comm=trace-cmd next_pid=16132 next_prio=120 Latency: 1155.677 usecs

           Average wakeup latency: 26626.656 usecs

       The above trace produces the wakeup latencies of the tasks. The
       "sched_switch" event reports each individual latency after
       writing the event information. At the end of the report, the
       average wakeup latency is reported.

             # trace-cmd report -w -F 'sched_switch, sched_wakeup.*: prio < 100 || next_prio < 100'
                     <idle>-0     [003] 158131.516753: sched_wakeup: comm=ksoftirqd/3 pid=13 prio=49 success=1 target_cpu=003
                     <idle>-0     [003] 158131.516855: sched_switch: prev_comm=swapper prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=ksoftirqd/3 next_pid=13 next_prio=49 Latency: 101.244 usecs
                     <idle>-0     [003] 158131.533781: sched_wakeup: comm=ksoftirqd/3 pid=13 prio=49 success=1 target_cpu=003
                     <idle>-0     [003] 158131.533897: sched_switch: prev_comm=swapper prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=ksoftirqd/3 next_pid=13 next_prio=49 Latency: 115.608 usecs
                     <idle>-0     [003] 158131.569730: sched_wakeup: comm=ksoftirqd/3 pid=13 prio=49 success=1 target_cpu=003
                     <idle>-0     [003] 158131.569851: sched_switch: prev_comm=swapper prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=ksoftirqd/3 next_pid=13 next_prio=49 Latency: 121.024 usecs

           Average wakeup latency: 110.021 usecs

       The above version will only show the wakeups and context switches
       of Real Time tasks. The prio used inside the kernel starts at 0
       for highest priority. That is prio 0 is equivalent to user space
       real time priority 99, and priority 98 is equivalent to user
       space real time priority 1. Prios less than 100 represent Real
       Time tasks.

       An example of the profile:

            # trace-cmd record --profile sleep 1
            # trace-cmd report --profile --comm sleep
           task: sleep-21611
             Event: sched_switch:R (1) Total: 99442 Avg: 99442 Max: 99442 Min:99442
                <stack> 1 total:99442 min:99442 max:99442 avg=99442
                  => ftrace_raw_event_sched_switch (0xffffffff8105f812)
                  => __schedule (0xffffffff8150810a)
                  => preempt_schedule (0xffffffff8150842e)
                  => ___preempt_schedule (0xffffffff81273354)
                  => cpu_stop_queue_work (0xffffffff810b03c5)
                  => stop_one_cpu (0xffffffff810b063b)
                  => sched_exec (0xffffffff8106136d)
                  => do_execve_common.isra.27 (0xffffffff81148c89)
                  => do_execve (0xffffffff811490b0)
                  => SyS_execve (0xffffffff811492c4)
                  => return_to_handler (0xffffffff8150e3c8)
                  => stub_execve (0xffffffff8150c699)
             Event: sched_switch:S (1) Total: 1000506680 Avg: 1000506680 Max: 1000506680 Min:1000506680
                <stack> 1 total:1000506680 min:1000506680 max:1000506680 avg=1000506680
                  => ftrace_raw_event_sched_switch (0xffffffff8105f812)
                  => __schedule (0xffffffff8150810a)
                  => schedule (0xffffffff815084b8)
                  => do_nanosleep (0xffffffff8150b22c)
                  => hrtimer_nanosleep (0xffffffff8108d647)
                  => SyS_nanosleep (0xffffffff8108d72c)
                  => return_to_handler (0xffffffff8150e3c8)
                  => tracesys_phase2 (0xffffffff8150c304)
             Event: sched_wakeup:21611 (1) Total: 30326 Avg: 30326 Max: 30326 Min:30326
                <stack> 1 total:30326 min:30326 max:30326 avg=30326
                  => ftrace_raw_event_sched_wakeup_template (0xffffffff8105f653)
                  => ttwu_do_wakeup (0xffffffff810606eb)
                  => ttwu_do_activate.constprop.124 (0xffffffff810607c8)
                  => try_to_wake_up (0xffffffff8106340a)

SEE ALSO         top

       trace-cmd(1), trace-cmd-record(1), trace-cmd-start(1),
       trace-cmd-stop(1), trace-cmd-extract(1), trace-cmd-reset(1),
       trace-cmd-split(1), trace-cmd-list(1), trace-cmd-listen(1),

AUTHOR         top

       Written by Steven Rostedt, <[1]>

RESOURCES         top


COPYING         top

       Copyright (C) 2010 Red Hat, Inc. Free use of this software is
       granted under the terms of the GNU Public License (GPL).

NOTES         top


COLOPHON         top

       This page is part of the trace-cmd (a front-end for Ftrace)
       project.  Information about the project can be found at [unknown
       -- if you know, please contact] If you have a
       bug report for this manual page, send it to Steven Rostedt
       <>.  This page was obtained from the project's
       upstream Git repository
       on 2020-12-18.  (At that time, the date of the most recent commit
       that was found in the repository was 2020-12-16.)  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

                               12/16/2020            TRACE-CMD-REPORT(1)

Pages that refer to this page: trace-cmd(1)trace-cmd-check-events(1)trace-cmd-clear(1)trace-cmd-extract(1)trace-cmd-hist(1)trace-cmd-list(1)trace-cmd-listen(1)trace-cmd-mem(1)trace-cmd-profile(1)trace-cmd-record(1)trace-cmd-reset(1)trace-cmd-restore(1)trace-cmd-set(1)trace-cmd-show(1)trace-cmd-snapshot(1)trace-cmd-split(1)trace-cmd-stack(1)trace-cmd-start(1)trace-cmd-stat(1)trace-cmd-stop(1)trace-cmd-stream(1)trace-cmd.dat(5)