NAME¶

SYNOPSIS¶

DESCRIPTION¶

OPTIONS¶

--flat

Print flat format rather than C-like format. This is usually for debugging and testing purpose.

-F FUNC, --filter=FUNC

Set filter to trace selected functions only. This option can be used more than once. See FILTERS.

-N FUNC, --notrace=FUNC

Set filter not to trace selected functions (or the functions called underneath them). This option can be used more than once. See FILTERS.

-T TRG, --trigger=TRG

Set trigger on selected functions. This option can be used more than once. See TRIGGERS.

-t TIME, --time-filter=TIME

Do not show functions which run under the time threshold. If some functions explicitly have the `trace' trigger applied, those are always traced regardless of execution time.

--tid=TID[,TID,...]

Only print functions called by the given threads. To see the list of threads in the data file, you can use uftrace report --threads or uftrace info. This option can also be used more than once.

-D DEPTH, --depth DEPTH

Set trace limit in nesting level.

-f FIELD, --output-fields=FIELD

Customize field in the output. Possible values are: duration, tid, addr, time, delta, elapsed, task and module. Multiple fields can be set by using comma. Special field of `none' can be used (solely) to hide all fields. Default is `duration,tid'. See FIELDS.

-r RANGE, --time-range=RANGE

Only show functions executed within the time RANGE. The RANGE can be <start>~<stop> (separated by “~”) and one of <start> and <stop> can be omitted. The <start> and <stop> are timestamp or elapsed time if they have <time_unit> postfix, for example `100us'. The timestamp or elapsed time can be shown with -f time or -f elapsed option respectively.

--disable

Start uftrace with tracing disabled. This is only meaningful when used with a trace_on trigger.

--demangle=TYPE

Use demangled C++ symbol names for filters, triggers, arguments and/or return values. Possible values are “full”, “simple” and “no”. Default is “simple” which ignores function arguments and template parameters.

–column-view

Show each task in separate column. This makes easy to distinguish functions in different tasks.

–column-offset=DEPTH

When --column-view option is used, this option specifies the amount of offset between each task. Default is 8.

–task-newline

Interleave a new line when task is changed. This makes easy to distinguish functions in different tasks.

–no-comment

Do not show comments of returned functions.

-k, --kernel

Trace kernel functions (and events) as well as user functions (and events). This options has no meaning and so is deprecated now. It will always show kernel functions and events if exists. If you want to hide kernel functions, please use -N .@kernel to filter out all kernel functions (for the regex match).

--kernel-full

Show all kernel functions and events occurred outside of user functions. This option is the inverse of --kernel-skip-out.

--kernel-skip-out

Do not show kernel functions called outside of user functions. This option is deprecated and set to true by default.

--kernel-only

Show kernel functions only without user functions.

--event-full

Show all (user) events outside of user functions.

--no-event

Do not show any events.

--libname

Show libname name along with function name.

–match=TYPE

Use pattern match using TYPE. Possible types are regex and glob. Default is regex.

FILTERS¶

The first one is an opt-in filter. By default, it doesn't show anything. But when one of the specified functions is met, printing is started. When the function returns, printing is stopped again.

For example, consider a simple program which calls a(), b() and c() in turn.

$ cat abc.c
void c(void) {
    /* do nothing */
}
void b(void) {
    c();
}
void a(void) {
    b();
}
int main(void) {
    a();
    return 0;
}
$ gcc -pg -o abc abc.c

    

Normally uftrace replay will show all the functions from main() to c().

$ uftrace ./abc
# DURATION    TID     FUNCTION
 138.494 us [ 1234] | __cxa_atexit();
            [ 1234] | main() {
            [ 1234] |   a() {
            [ 1234] |     b() {
   3.880 us [ 1234] |       c();
   5.475 us [ 1234] |     } /* b */
   6.448 us [ 1234] |   } /* a */
   8.631 us [ 1234] | } /* main */

    

But when the -F b filter option is used, it will not show main() or a() but only b() and c(). Note that the filter was set on uftrace replay, not at record time.

$ uftrace record ./abc
$ uftrace replay -F b
# DURATION    TID     FUNCTION
            [ 1234] | b() {
   3.880 us [ 1234] |   c();
   5.475 us [ 1234] | } /* b */

    

The second type of filter is opt-out. When used, everything is shown by default, but printing stops once one of the specified functions is met. When the given function returns, printing is started again.

In the above example, you can omit the function b() and all calls it makes with the -N option.

$ uftrace record ./abc
$ uftrace replay -N b
# DURATION    TID     FUNCTION
 138.494 us [ 1234] | __cxa_atexit();
            [ 1234] | main() {
   6.448 us [ 1234] |   a();
   8.631 us [ 1234] | } /* main */

    

In addition, you can limit the print nesting level with -D option.

$ uftrace record ./abc
$ uftrace replay -D 3
# DURATION    TID     FUNCTION
 138.494 us [ 1234] | __cxa_atexit();
            [ 1234] | main() {
            [ 1234] |   a() {
   5.475 us [ 1234] |     b();
   6.448 us [ 1234] |   } /* a */
   8.631 us [ 1234] | } /* main */

    

In the above example, uftrace only prints functions up to a depth of 3, so leaf function c() was omitted. Note that the -D option also works with -F.

Sometimes it's useful to see long-running functions only. This is good because there are usually many tiny functions that are not interesting. The -t/--time-filter option implements the time-based filter that only records functions which run longer than the given threshold. In the above example, the user might want to see functions running more than 5 microseconds like below:

$ uftrace record ./abc
$ uftrace replay -t 5us
# DURATION    TID     FUNCTION
 138.494 us [ 1234] | __cxa_atexit();
            [ 1234] | main() {
            [ 1234] |   a() {
   5.475 us [ 1234] |     b();
   6.448 us [ 1234] |   } /* a */
   8.631 us [ 1234] | } /* main */

    

You can also see replay output with different time threshold for the same recorded data.

$ uftrace replay -t 6us
# DURATION    TID     FUNCTION
 138.494 us [ 1234] | __cxa_atexit();
            [ 1234] | main() {
   6.448 us [ 1234] |   a();
   8.631 us [ 1234] | } /* main */

    

In addition, The -r option can show functions executed within the given time range. When using this option, you can see TIMESTAMP or ELAPSED fields as well as DURATION and TID.

$ uftrace replay -r 502716.387320101~502716.387322389
#     TIMESTAMP      DURATION    TID     FUNCTION
502716.387320101   0.289 us [ 6126] |   fgets();
502716.387320584            [ 6126] |   get_values_from() {
502716.387320709   0.245 us [ 6126] |     strdup();
502716.387321172   0.144 us [ 6126] |     strsep();
502716.387321542   0.223 us [ 6126] |     atoi();
502716.387321983   0.239 us [ 6126] |     atoi();
502716.387322389   1.805 us [ 6126] |   } /* get_values_from */
$ uftrace replay -r 40us~ | head -10
#  ELAPSED   DURATION    TID     FUNCTION
  40.141 us            [ 6126] |   get_values_from() {
  40.269 us   0.249 us [ 6126] |     strdup();
  40.756 us   0.149 us [ 6126] |     strsep();
  41.119 us   0.235 us [ 6126] |     atoi();
  41.578 us   0.211 us [ 6126] |     atoi();
  41.957 us   1.816 us [ 6126] |   } /* get_values_from */
  42.124 us   0.220 us [ 6126] |   fgets();
  42.529 us            [ 6126] |   get_values_from() {
  42.645 us   0.236 us [ 6126] |     strdup();

    

You can also set triggers on filtered functions. See TRIGGERS section below for details.

TRIGGERS¶

<trigger>    :=  <symbol> "@" <actions>
<actions>    :=  <action>  | <action> "," <actions>
<action>     :=  "depth="<num> | "backtrace" | "trace_on" | "trace_off" |
                 "color="<color> | "time="<time_spec> | "filter" | "notrace"
<time_spec>  :=  <num> [ <time_unit> ]
<time_unit>  :=  "ns" | "nsec" | "us" | "usec" | "ms" | "msec" | "s" | "sec" | "m" | "min"

    

The depth trigger is to change filter depth during execution of the function. It can be used to apply different filter depths for different functions. And the backtrace trigger is used to print a stack backtrace at replay time.

The color trigger is to change the color of the function in replay output. The supported colors are red, green, blue, yellow, magenta, cyan, bold, and gray.

The following example shows how triggers work. We set a filter on function b() with the backtrace action and change the maximum filter depth under b() to 2.

$ uftrace record ./abc
$ uftrace replay -T 'b@filter,backtrace,depth=2'
# DURATION    TID     FUNCTION
  backtrace [ 1234] | /* [ 0] main */
  backtrace [ 1234] | /* [ 1] a */
            [ 1234] | b {
   3.880 us [ 1234] |   c();
   5.475 us [ 1234] | } /* b */

    

The traceon and traceoff actions (the _ can be omitted from trace_on and trace_off) control whether uftrace shows functions or not. The trigger runs at replay time, not run time, so it can handle kernel functions as well. Contrast this with triggers used under uftrace record.

The `time' trigger is to change time filter setting during execution of the function. It can be used to apply different time filter for different functions.

The `filter' and `notrace' triggers have same effect as -F/–filter and -N/–notrace options respectively.

FIELDS¶

$ uftrace replay -f time,delta,duration,addr
#     TIMESTAMP      TIMEDELTA  DURATION     ADDRESS     FUNCTION
    74469.340757350              1.583 us       4004d0 | __monstartup();
    74469.340762221   4.871 us   0.766 us       4004f0 | __cxa_atexit();
    74469.340764847   2.626 us                  4006b1 | main() {
    74469.340765061   0.214 us                  400656 |   a() {
    74469.340765195   0.134 us                  400669 |     b() {
    74469.340765344   0.149 us                  40067c |       c() {
    74469.340765524   0.180 us   0.742 us       4004b0 |         getpid();
    74469.340766935   1.411 us   1.591 us       40067c |       } /* c */
    74469.340767195   0.260 us   2.000 us       400669 |     } /* b */
    74469.340767372   0.177 us   2.311 us       400656 |   } /* a */
    74469.340767541   0.169 us   2.694 us       4006b1 | } /* main */

    

Each field has following meaning:

•

tid: task id (obtained by gettid(2))

•

duration: function execution time

•

time: timestamp at the execution

•

delta: difference between two timestamp in a task

•

elapsed: elapsed time from the first timestamp

•

addr: address of the function

•

task: task name (comm)

•

module: library or executable name of the function

The default value is `duration,tid'. If given field name starts with “+”, then it'll be appended to the default fields. So “-f +time” is as same as “-f duration,tid,time”. And it also accepts a special field name of `none' which disables the field display and shows function output only.

SEE ALSO¶

AUTHORS¶