kernel.git/tools/perf/util/callchain.h, branch linux-4.12.y

perf report: Enable sorting by srcline as key

2017-03-27T15:13:28Z

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 Cc: Jiri Olsa Cc: Yao Jin Link: http://lkml.kernel.org/r/20170318214928.9047-1-milian.wolff@kdab.com Signed-off-by: Arnaldo Carvalho de Melo

perf callchain: Reference count maps

2017-02-02T14:39:09Z

If dso__load_kcore frees all of the existing maps, but one has already been attached to a callchain cursor node, then we can get a SIGSEGV in any function that happens to try to use this invalid cursor. Use the existing map refcount mechanism to forestall cleanup of a map until the cursor iterates past the node. Signed-off-by: Krister Johansen Tested-by: Arnaldo Carvalho de Melo Cc: Frederic Weisbecker Cc: Masami Hiramatsu Cc: Namhyung Kim Cc: stable@kernel.org Fixes: 84c2cafa2889 ("perf tools: Reference count struct map") Link: http://lkml.kernel.org/r/20170106062331.GB2707@templeofstupid.com Signed-off-by: Arnaldo Carvalho de Melo

perf callchain: Introduce callchain_cursor__copy()

2016-12-07T15:00:33Z

The callchain_cursor__copy() function is to save current callchain captured by a cursor. It'll be used to keep callchains when switching to idle task for each cpu. Signed-off-by: Namhyung Kim Cc: Andi Kleen Cc: David Ahern Cc: Jiri Olsa Cc: Minchan Kim Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/20161206034010.6499-3-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf report: Calculate and return the branch flag counting

2016-11-14T16:25:58Z

Create some branch counters in per callchain list entry. Each counter is for a branch flag. For example, predicted_count counts all the *predicted* branches. The counters get updated by processing the callchain cursor nodes. It also provides functions to retrieve or print the values of counters in callchain list. Besides the counting for branch flags, it also counts and returns the average number of iterations. Signed-off-by: Yao Jin Acked-by: Andi Kleen Cc: Jiri Olsa Cc: Kan Liang Cc: Linux-kernel@vger.kernel.org Cc: Yao Jin Link: http://lkml.kernel.org/r/1477876794-30749-4-git-send-email-yao.jin@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo

perf report: Add branch flag to callchain cursor node

2016-11-14T16:15:56Z

Since the branch ip has been added to call stack for easier browsing, this patch adds more branch information. For example, add a flag to indicate if this ip is a branch, and also add with the branch flag. Then we can know if the cursor node represents a branch and know what the branch flag it has. The branch history code has a loop detection pass that removes loops. It would be nice for knowing how many loops were removed then in next steps, we can compute out the average number of iterations. For example: Before remove_loops(), entry0: from = 0x100, to = 0x200 entry1: from = 0x300, to = 0x250 entry2: from = 0x300, to = 0x250 entry3: from = 0x300, to = 0x250 entry4: from = 0x700, to = 0x800 After remove_loops() entry0: from = 0x100, to = 0x200 entry1: from = 0x300, to = 0x250 entry2: from = 0x700, to = 0x800 The original entry2 and entry3 are removed. So the number of iterations (from = 0x300, to = 0x250) is equal to removed number + 1 (2 + 1). iterations = removed number + 1; average iteractions = Sum(iteractions) / number of samples This formula ignores other cases, for example, iterations cross multiple buffers and one buffer contains 2+ loops. Because in practice, it's good enough. Signed-off-by: Yao Jin Acked-by: Andi Kleen Cc: Jiri Olsa Cc: Kan Liang Cc: Linux-kernel@vger.kernel.org Cc: Yao Jin Link: http://lkml.kernel.org/n/1477876794-30749-2-git-send-email-yao.jin@linux.intel.com [ Renamed 'iter' to 'nr_loop_iter' for clarity ] Signed-off-by: Arnaldo Carvalho de Melo

perf callchain: Fixup help/config for no-unwinding

2016-11-08T01:13:47Z

Since 841e3558b2d ("perf callchain: Recording 'dwarf' callchains do not need DWARF unwinding support"), --call-graph dwarf is allowed in 'perf record' even without unwind support. A couple of other places don't reflect this yet though: the help text should list dwarf as a valid record mode and the dump_size config should be respected too. Signed-off-by: Rabin Vincent Cc: He Kuang Fixes: 841e3558b2de ("perf callchain: Recording 'dwarf' callchains do not need DWARF unwinding support") Link: http://lkml.kernel.org/r/1470837148-7642-1-git-send-email-rabin.vincent@axis.com Signed-off-by: Arnaldo Carvalho de Melo

perf tests: Fix hist accumulation test

2016-07-04T22:39:01Z

User's values from .perfconfig could overload the default callchain setup and cause this test to fail. Making sure the test is using default callchain_param values. Signed-off-by: Jiri Olsa Cc: David Ahern Cc: Namhyung Kim Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1467634583-29147-3-git-send-email-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Per event max-stack settings

2016-05-30T15:41:44Z

The tooling counterpart, now it is possible to do: # perf record -e sched:sched_switch/max-stack=10/ -e cycles/call-graph=dwarf,max-stack=4/ -e cpu-cycles/call-graph=dwarf,max-stack=1024/ usleep 1 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.052 MB perf.data (5 samples) ] # perf evlist -v sched:sched_switch: type: 2, size: 112, config: 0x110, { sample_period, sample_freq }: 1, sample_type: IP|TID|TIME|CALLCHAIN|CPU|PERIOD|RAW|IDENTIFIER, read_format: ID, disabled: 1, inherit: 1, mmap: 1, comm: 1, enable_on_exec: 1, task: 1, sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1, sample_max_stack: 10 cycles/call-graph=dwarf,max-stack=4/: size: 112, { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|CALLCHAIN|PERIOD|REGS_USER|STACK_USER|IDENTIFIER, read_format: ID, disabled: 1, inherit: 1, freq: 1, enable_on_exec: 1, sample_id_all: 1, exclude_guest: 1, exclude_callchain_user: 1, sample_regs_user: 0xff0fff, sample_stack_user: 8192, sample_max_stack: 4 cpu-cycles/call-graph=dwarf,max-stack=1024/: size: 112, { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|CALLCHAIN|PERIOD|REGS_USER|STACK_USER|IDENTIFIER, read_format: ID, disabled: 1, inherit: 1, freq: 1, enable_on_exec: 1, sample_id_all: 1, exclude_guest: 1, exclude_callchain_user: 1, sample_regs_user: 0xff0fff, sample_stack_user: 8192, sample_max_stack: 1024 # Tip: use 'perf evlist --trace-fields' to show fields for tracepoint events Using just /max-stack=N/ means /call-graph=fp,max-stack=N/, that should be further configurable by means of some .perfconfig knob. Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Alexei Starovoitov Cc: Brendan Gregg Cc: David Ahern Cc: Frederic Weisbecker Cc: He Kuang Cc: Jiri Olsa Cc: Linus Torvalds Cc: Masami Hiramatsu Cc: Milian Wolff Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Vince Weaver Cc: Wang Nan Cc: Zefan Li Link: http://lkml.kernel.org/n/tip-kolmn1yo40p7jhswxwrc7rrd@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf record: Export record_opts based callchain parsing helper

2016-04-15T19:37:17Z

To be able to call it outside option parsing, like when setting a default --call-graph parameter in 'perf trace' when just --min-stack is used. Cc: Adrian Hunter Cc: David Ahern Cc: Jiri Olsa Cc: Namhyung Kim Cc: Wang Nan Link: http://lkml.kernel.org/n/tip-xay69plylwibpb3l4isrpl1k@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf callchain: Start moving away from global per thread cursors

2016-04-14T17:48:07Z

The recent perf_evsel__fprintf_callchain() move to evsel.c added several new symbol requirements to the python binding, for instance: # perf test -v python 16: Try 'import perf' in python, checking link problems : --- start --- test child forked, pid 18030 Traceback (most recent call last): File "", line 1, in ImportError: /tmp/build/perf/python/perf.so: undefined symbol: callchain_cursor test child finished with -1 ---- end ---- Try 'import perf' in python, checking link problems: FAILED! # This would require linking against callchain.c to access to the global callchain_cursor variables. Since lots of functions already receive as a parameter a callchain_cursor struct pointer, make that be the case for some more function so that we can start phasing out usage of yet another global variable. Cc: Adrian Hunter Cc: David Ahern Cc: Frederic Weisbecker Cc: Jiri Olsa Cc: Namhyung Kim Cc: Wang Nan Link: http://lkml.kernel.org/n/tip-djko3097eyg2rn66v2qcqfvn@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo