The compiler might optimize a call/ret combination by making it a jmp.
However the thread-stack does not presently cater for that, so that such
control flow is not visible in the call graph. Make it visible by
recording on the stack a branch to the start of a different symbol.
Note, that means when a ret pops the stack, all jmps must be popped off
first.
Example:
$ cat jmp-to-fn.c
__attribute__((noinline)) int bar(void)
{
return -1;
}
__attribute__((noinline)) int foo(void)
{
return bar() + 1;
}
int main()
{
return foo();
}
$ gcc -ggdb3 -Wall -Wextra -O2 -o jmp-to-fn jmp-to-fn.c
$ objdump -d jmp-to-fn
<SNIP>
0000000000001040 <main>:
1040: 31 c0 xor %eax,%eax
1042: e9 09 01 00 00 jmpq 1150 <foo>
<SNIP>
0000000000001140 <bar>:
1140: b8 ff ff ff ff mov $0xffffffff,%eax
1145: c3 retq
<SNIP>
0000000000001150 <foo>:
1150: 31 c0 xor %eax,%eax
1152: e8 e9 ff ff ff callq 1140 <bar>
1157: 83 c0 01 add $0x1,%eax
115a: c3 retq
<SNIP>
$ perf record -o jmp-to-fn.perf.data -e intel_pt/cyc/u ./jmp-to-fn
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0,017 MB jmp-to-fn.perf.data ]
$ perf script -i jmp-to-fn.perf.data --itrace=be -s ~/libexec/perf-core/scripts/python/export-to-sqlite.py jmp-to-fn.db branches calls
2019-01-08 13:24:58.783069 Creating database...
2019-01-08 13:24:58.794650 Writing records...
2019-01-08 13:24:59.008050 Adding indexes
2019-01-08 13:24:59.015802 Done
$ ~/libexec/perf-core/scripts/python/exported-sql-viewer.py jmp-to-fn.db
Before:
main
-> bar
After:
main
-> foo
-> bar
Committer testing:
Install the python2-pyside package, then select these menu options
on the GUI:
"Reports"
"Context sensitive callgraphs"
Then go on expanding the symbols, to get, full picture when doing this
on a fedora:29 with gcc version 8.2.1 20181215 (Red Hat 8.2.1-6) (GCC):
jmp-to-fn
PID:TID
_start (ld-2.28.so)
__libc_start_main
main
foo
bar
To verify that indeed, this fixes the problem.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: http://lkml.kernel.org/r/20190109091835.5570-5-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Displaying all the database tables can help make the database easier to
understand.
Committer testing:
Opened all the tables, even the sqlite master table, which I selected
everything and used control+C, lets see if it works...
CREATE VIEW threads_view AS SELECT id,machine_id,(SELECT host_or_guest FROM machines_view WHERE id = machine_id) AS host_or_guest,process_id,pid,tid FROM threads
Humm, nope, just one of the cells got copied, even with everything selected :-)
Anyway, works as advertised, useful for perusing the data.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/20181001062853.28285-17-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Add a Find bar that appears at the bottom of the call-graph window.
Committer testing:
Using:
python tools/perf/scripts/python/exported-sql-viewer.py pt_example branches calls
Using the database built in the first "Committer Testing" section in
this patch series I was able to:
"Reports"
"Context-Sensitive Call Graphs"
Control+F or select "Edit" in the top menu then "Find"
__poll<ENTER>
and find the first place where the "__poll" function appears, then
press the down arrow in the lower right corner and go to the next, etc.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/20181001062853.28285-15-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Use Qt MDI (multiple document interface) to support multiple sub-windows.
Put the data model in a cache so that each sub-window can share the same
data. This allows mutiple views of the call-graph at the same time and
paves the way to add more reports.
Committer testing:
Starts with a "File Reports Windows" main menu, from the "Reports" I
can get what was available up to now, the "Context-Sensitivi Call Graph"
option.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/20181001062853.28285-14-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
class TreeItem represents items at all levels of the call-graph tree.
However, not all the levels represent the same data i.e. the top-level is
comms, the next level is threads, and subsequent levels are functions.
Consequently it is simpler to have separate classes for different levels
with commonality in a base class. Refactor TreeItem class accordingly.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/20181001062853.28285-12-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Set initial column sizes to improve initial display.
Committer testing:
Extended instructions on testing this, using the sqlite variant:
Make sure you have the SQLite glue for python+Qt installed, on fedora 27
I used:
# dnf install python-pyside
Collect some PT samples, say 5-secs worth, system wide:
# perf record -r 10 -e intel_pt//u -a sleep 5
[ perf record: Woken up 49 times to write data ]
[ perf record: Captured and wrote 96.131 MB perf.data ]
This results in this perf.data file:
# ls -larth perf.data
-rw-------. 1 root root 97M Oct 23 10:11 perf.data
With the following attributes:
# perf evlist -v
intel_pt//u: type: 8, size: 112, config: 0x300e601, { sample_period, sample_freq }: 1, sample_type: IP|TID|TIME|CPU|IDENTIFIER, read_format: ID, disabled: 1, inherit: 1, exclude_kernel: 1, exclude_hv: 1, sample_id_all: 1
dummy:u: type: 1, size: 112, config: 0x9, { sample_period, sample_freq }: 1, sample_type: IP|TID|TIME|CPU|IDENTIFIER, read_format: ID, inherit: 1, exclude_kernel: 1, exclude_hv: 1, mmap: 1, comm: 1, task: 1, sample_id_all: 1, mmap2: 1, comm_exec: 1, context_switch: 1
#
Then generate the "pt_example" tables using:
# perf script -s ~/libexec/perf-core/scripts/python/export-to-sqlite.py pt_example branches calls
2018-10-23 10:56:59.177711 Creating database...
2018-10-23 10:56:59.195842 Writing records...
instruction trace error type 1 cpu 2 pid 1644 tid 1644 ip 0x263984516750 code 5: Failed to get instruction
instruction trace error type 1 cpu 2 pid 1644 tid 1644 ip 0x7f26e116fd20 code 6: Trace doesn't match instruction
instruction trace error type 1 cpu 2 pid 1644 tid 1644 ip 0x7f26e162c9ee code 6: Trace doesn't match instruction
instruction trace error type 1 cpu 2 pid 1644 tid 1644 ip 0x7f26e9ce831a code 6: Trace doesn't match instruction
<SNIP>
instruction trace error type 1 cpu 0 pid 1644 tid 1644 ip 0x7f26e13d07b4 code 6: Trace doesn't match instruction
Warning:
132 instruction trace errors
2018-10-23 11:25:25.015717 Adding indexes
2018-10-23 11:25:28.788061 Done
#
In my example, that perf.data file generated this db:
# file pt_example
pt_example: SQLite 3.x database, last written using SQLite version 3020001
[root@seventh perf]# ls -lah pt_example
-rw-r--r--. 1 root root 6.6G Oct 23 11:25 pt_example
#
Then use this python script to use that db and provide a GUI:
$ python tools/perf/scripts/python/call-graph-from-sql.py pt_example branches calls
I compared the column widths before this patch and after applying it,
the visual results match the patch intent.
The following patches will refer to this set of instructions in the "Committer
Testing" section.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/20181001062853.28285-3-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
