| UFTRACE-GRAPH(1) | UFTRACE-GRAPH(1) |
uftrace-graph - Show function call graph
uftrace graph [options] [FUNCTION]
This command shows a function call graph for the binary or the given function in a uftrace record datafile. If the function name is omitted, whole function call graph will be shown. If a user provides a function name, it will show backtrace and calling functions. Each function in the output is annotated with a hit count and the total time spent running that function.
This command show data like below:
$ uftrace record loop $ uftrace replay # DURATION TID FUNCTION
[24447] | main() {
[24447] | foo() {
8.134 us [24447] | loop();
7.296 us [24447] | loop();
7.234 us [24447] | loop();
24.324 us [24447] | } /* foo */
[24447] | foo() {
7.234 us [24447] | loop();
7.231 us [24447] | loop();
7.231 us [24447] | loop();
22.302 us [24447] | } /* foo */
[24447] | bar() {
10.100 ms [24447] | usleep();
10.138 ms [24447] | } /* bar */
10.293 ms [24447] | } /* main */
Running the graph command shows function call graph like below:
$ uftrace graph # Function Call Graph for 'loop' (session: 073f1e84aa8b09d3) ========== FUNCTION CALL GRAPH ==========
10.293 ms : (1) loop
10.293 ms : (1) main
46.626 us : +-(2) foo
44.360 us : | (6) loop
: |
10.138 ms : +-(1) bar
10.100 ms : (1) usleep
The graph root is not a function, but the executing process itself. The left side shows total time running the function on the right side. The number in parentheses before the function name is the invocation count. As you can see, main was called once and ran for 10 msec. It called foo twice and then foo called loop 6 times in total. The printed time is the total execution time for all function invocations.
It can also be seen that main called bar once and that bar then called usleep once. To minimize nesting, the output shows calls at the same level if only a single call path exists. Since the nodes usleep and main are not directly connected, usleep is not called from main directly.
Running the graph command on the main function shows called functions and backtrace like below:
$ uftrace graph main # Function Call Graph for 'main' (session: 073f1e84aa8b09d3) =============== BACKTRACE ===============
backtrace #0: hit 1, time 10.293 ms
[0] main (0x4004f0) ========== FUNCTION CALL GRAPH ========== # TOTAL TIME FUNCTION
10.293 ms : (1) main
46.626 us : +-(2) foo
44.360 us : | (6) loop
: |
10.138 ms : +-(1) bar
10.100 ms : (1) usleep
Note that the `main' is the top-level function so it has no backtrace above itself. Running the graph command on a leaf function looks like below.
$ uftrace graph loop # Function Call Graph for 'loop' (session: 073f1e84aa8b09d3) =============== BACKTRACE ===============
backtrace #0: hit 6, time 44.360 us
[0] main (0x4004b0)
[1] foo (0x400622)
[2] loop (0x400f5f6) ========== FUNCTION CALL GRAPH ========== # TOTAL TIME FUNCTION
44.360 us : (6) loop
The backtrace shows that loop is called from foo and that foo is called from main. Since loop is a leaf function, it didn’t call any other function. In this case, loop was called only from a single path so backtrace #0 is hit 6 times.
While graph command shows function-level call graph, –task option makes the output in task-level graph which shows how processes and threads are created. The term here task includes process and thread.
For example, the task graph of GCC compiler can be shown as follows:
$ uftrace record --force /usr/bin/gcc hello.c $ uftrace graph --task ========== TASK GRAPH ========== # TOTAL TIME SELF TIME TID TASK NAME
159.854 ms 4.440 ms [ 82723] : gcc
: |
90.951 ms 90.951 ms [ 82734] : +----cc1
: |
17.150 ms 17.150 ms [ 82735] : +----as
: |
45.183 ms 6.076 ms [ 82736] : +----collect2
: |
38.880 ms 38.880 ms [ 82737] : +----ld
The above output shows gcc created cc1, as, and collect2 processes then collect2 created ld process.
TOTAL TIME is the lifetime of the task from its creation to termination, and SELF TIME is also lifetime, but it excludes internal idle time. TID is the thread id of the task.
The following shows task graph of uftrace recording itself. It shows uftrace created t-abc process, and also created many threads whose names are all WriterThread.
$ uftrace record -P. ./uftrace record -d uftrace.data.abc t-abc $ uftrace graph --task ========== TASK GRAPH ========== # TOTAL TIME SELF TIME TID TASK NAME
404.929 ms 321.692 ms [ 4230] : uftrace
: |
278.662 us 278.662 us [ 4241] : +----t-abc
: |
33.754 ms 4.061 ms [ 4242] : +-WriterThread
27.415 ms 120.992 us [ 4244] : +-WriterThread
27.212 ms 8.119 ms [ 4245] : +-WriterThread
26.754 ms 6.616 ms [ 4248] : +-WriterThread
26.859 ms 8.154 ms [ 4247] : +-WriterThread
26.509 ms 1.645 ms [ 4243] : +-WriterThread
25.320 ms 57.350 us [ 4246] : +-WriterThread
24.757 ms 4.391 ms [ 4249] : +-WriterThread
26.040 ms 3.707 ms [ 4250] : +-WriterThread
24.004 ms 3.999 ms [ 4251] : +-WriterThread
Please note that the indentation depth of thread is different from process.
Running the graph command with --srcline option shows source location in call graph like below:
$ uftrace record --srcline t-abc $ uftrace graph --srcline # Function Call Graph for 't-abc' (session: 60195bac953d8736) ========== FUNCTION CALL GRAPH ========== # TOTAL TIME FUNCTION [SOURCE]
8.909 us : (1) t-abc
1.260 us : +-(1) __monstartup
: |
0.179 us : +-(1) __cxa_atexit
: |
7.470 us : +-(1) main [tests/s-abc.c:26]
5.522 us : (1) a [tests/s-abc.c:11]
4.912 us : (1) b [tests/s-abc.c:16]
4.176 us : (1) c [tests/s-abc.c:21]
0.794 us : (1) getpid
The uftrace allows for user to customize the graph output with some of fields. Here the field means info on the left side of the colon (:) character. By default it uses time only, but you can use other fields in any order like:
$ uftrace record tests/t-abc $ uftrace graph -f total,self,addr # Function Call Graph for 't-sort' (session: b007f4b7cf792878) ========== FUNCTION CALL GRAPH ========== # TOTAL TIME SELF TIME ADDRESS FUNCTION
10.145 ms 561f652cd610 : (1) t-sort
10.145 ms 39.890 us 561f652cd610 : (1) main
16.773 us 0.734 us 561f652cd7ce : +-(2) foo
16.039 us 16.039 us 561f652cd7a0 : | (6) loop
: |
10.088 ms 14.740 us 561f652cd802 : +-(1) bar
10.073 ms 10.073 ms 561f652cd608 : (1) usleep
Each field has following meaning:
The default value is `total'. If given field name starts with “+”, then it’ll be appended to the default fields. So “-f +addr” is as same as “-f total,addr”. And it also accepts a special field name of `none' which disables the field display and shows function output only.
$ uftrace graph -f none # Function Call Graph for 't-sort' (session: b007f4b7cf792878) ========== FUNCTION CALL GRAPH ========== (1) t-sort (1) main
+-(2) foo
| (6) loop
|
+-(1) bar
(1) usleep
This output can be useful when comparing two different call graph outputs using diff tool.
It also supports field customization for task graph. The default field is set to total,self,tid, but the field option can also be used as follows:
$ uftrace graph --task -f tid,self ========== TASK GRAPH ========== # TID SELF TIME TASK NAME
[ 82723] 4.440 ms : gcc
: |
[ 82734] 90.951 ms : +----cc1
: |
[ 82735] 17.150 ms : +----as
: |
[ 82736] 6.076 ms : +----collect2
: |
[ 82737] 38.880 ms : +----ld
Each field has following meaning:
It also accepts a special field none, which hides all the fields on the left.
$ uftrace graph --task -f none ========== TASK GRAPH ========== gcc
|
+----cc1
|
+----as
|
+----collect2
|
+----ld
uftrace(1), uftrace-record(1), uftrace-replay(1), uftrace-tui(1)
Namhyung Kim <namhyung@gmail.com>.
| Sep, 2018 | Uftrace User Manuals |