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Often it is interesting to know how costly a given source line is in
total. Previously, one had to build these sums manually based on all
addresses that pointed to the same source line. This patch introduces
srcline as a sort key, which will do the aggregation for us.
Paired with the recent addition of showing inline frames, this makes
perf report much more useful for many C++ work loads.
The following shows the new feature in action. First, let's show the
status quo output when we sort by address. The result contains many hist
entries that generate the same output:
~~~~~~~~~~~~~~~~
$ perf report --stdio --inline -g address
# Children Self Command Shared Object Symbol
# ........ ........ ............ ................... .........................................
#
99.89% 35.34% cpp-inlining cpp-inlining [.] main
|
|--64.55%--main complex:655
| /home/milian/projects/kdab/rnd/hotspot/tests/test-clients/cpp-inlining/main.cpp:39 (inline)
| /usr/include/c++/6.3.1/complex:664 (inline)
| |
| |--60.31%--hypot +20
| | |
| | |--8.52%--__hypot_finite +273
| | |
| | |--7.32%--__hypot_finite +411
...
--35.34%--_start +4194346
__libc_start_main +241
|
|--6.65%--main random.tcc:3326
| /home/milian/projects/kdab/rnd/hotspot/tests/test-clients/cpp-inlining/main.cpp:39 (inline)
| /usr/include/c++/6.3.1/bits/random.h:1809 (inline)
| /usr/include/c++/6.3.1/bits/random.h:1818 (inline)
| /usr/include/c++/6.3.1/bits/random.h:185 (inline)
|
|--2.70%--main random.tcc:3326
| /home/milian/projects/kdab/rnd/hotspot/tests/test-clients/cpp-inlining/main.cpp:39 (inline)
| /usr/include/c++/6.3.1/bits/random.h:1809 (inline)
| /usr/include/c++/6.3.1/bits/random.h:1818 (inline)
| /usr/include/c++/6.3.1/bits/random.h:185 (inline)
|
|--1.69%--main random.tcc:3326
| /home/milian/projects/kdab/rnd/hotspot/tests/test-clients/cpp-inlining/main.cpp:39 (inline)
| /usr/include/c++/6.3.1/bits/random.h:1809 (inline)
| /usr/include/c++/6.3.1/bits/random.h:1818 (inline)
| /usr/include/c++/6.3.1/bits/random.h:185 (inline)
...
~~~~~~~~~~~~~~~~
With this patch and `-g srcline` we instead get the following output:
~~~~~~~~~~~~~~~~
$ perf report --stdio --inline -g srcline
# Children Self Command Shared Object Symbol
# ........ ........ ............ ................... .........................................
#
99.89% 35.34% cpp-inlining cpp-inlining [.] main
|
|--64.55%--main complex:655
| /home/milian/projects/kdab/rnd/hotspot/tests/test-clients/cpp-inlining/main.cpp:39 (inline)
| /usr/include/c++/6.3.1/complex:664 (inline)
| |
| |--64.02%--hypot
| | |
| | --59.81%--__hypot_finite
| |
| --0.53%--cabs
|
--35.34%--_start
__libc_start_main
|
|--12.48%--main random.tcc:3326
| /home/milian/projects/kdab/rnd/hotspot/tests/test-clients/cpp-inlining/main.cpp:39 (inline)
| /usr/include/c++/6.3.1/bits/random.h:1809 (inline)
| /usr/include/c++/6.3.1/bits/random.h:1818 (inline)
| /usr/include/c++/6.3.1/bits/random.h:185 (inline)
...
~~~~~~~~~~~~~~~~
Signed-off-by: Milian Wolff <milian.wolff@kdab.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Yao Jin <yao.jin@linux.intel.com>
Link: http://lkml.kernel.org/r/20170318214928.9047-1-milian.wolff@kdab.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.