linux.git/tools/perf/util/machine.c, branch v4.11

perf tools: Be consistent on the type of map->symbols[] interator

2017-02-14T19:19:56+00:00

In a few cases we were using 'enum map_type' and that triggered this
warning when using clang:

  util/session.c:1923:16: error: comparison of constant 2 with expression of type 'enum map_type' is always true
      [-Werror,-Wtautological-constant-out-of-range-compare]
        for (i = 0; i < MAP__NR_TYPES; ++i) {

Cc: Adrian Hunter 
Cc: David Ahern 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Wang Nan 
Link: http://lkml.kernel.org/n/tip-i6uyo6bsopa2dghnx8qo7rri@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf symbols: No need to check if sym->name is NULL

2017-02-13T20:22:34+00:00

As it is an array, so will always evaluate to 'true', as reported by
clang:

  builtin-sched.c:2070:19: error: address of array 'sym->name' will always evaluate to 'true' [-Werror,-Wpointer-bool-conversion]
                  if (sym && sym->name) {
                          ~~ ~~~~~^~~~
  1 warning generated.

So just ditch all those useless checks.

Cc: Adrian Hunter 
Cc: David Ahern 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Wang Nan 
Link: http://lkml.kernel.org/n/tip-ydpm927col06paixb775jjx5@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf machine: Add a kallsyms loading constructor

2017-01-11T19:48:00+00:00

To reduce the boilerplate for searching for functions in the running
kernel and modules.

Cc: Adrian Hunter 
Cc: David Ahern 
Cc: Jiri Olsa 
Cc: Masami Hiramatsu 
Cc: Namhyung Kim 
Cc: Wang Nan 
Link: http://lkml.kernel.org/n/tip-93iqzayafpaxaguoiwjqezgz@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf report: Add branch flag to callchain cursor node

2016-11-14T16:15:56+00:00

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 tools: Experiment with cppcheck

2016-10-03T14:24:13+00:00

Experimenting a bit using cppcheck[1], a static checker brought to my
attention by Colin, reducing the scope of some variables, reducing the
line of source code lines in the process:

  $ cppcheck --enable=style tools/perf/util/thread.c
  Checking tools/perf/util/thread.c...
  [tools/perf/util/thread.c:17]: (style) The scope of the variable 'leader' can be reduced.
  [tools/perf/util/thread.c:133]: (style) The scope of the variable 'err' can be reduced.
  [tools/perf/util/thread.c:273]: (style) The scope of the variable 'err' can be reduced.

Will continue later, but these are already useful, keep them.

1: https://sourceforge.net/p/cppcheck/wiki/Home/

Cc: Adrian Hunter 
Cc: Colin Ian King 
Cc: David Ahern 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Wang Nan 
Link: http://lkml.kernel.org/n/tip-ixws7lbycihhpmq9cc949ti6@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf symbols: Remove symbol_filter_t machinery

2016-09-05T14:14:50+00:00

We're not using it anymore, few users were, but we really could do
without it, simplify lots of functions by removing it.

Cc: Adrian Hunter 
Cc: David Ahern 
Cc: Jiri Olsa 
Cc: Masami Hiramatsu 
Cc: Namhyung Kim 
Cc: Wang Nan 
Link: http://lkml.kernel.org/n/tip-1zng8wdznn00iiz08bb7q3vn@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf machine: Remove machine->symbol_filter and friends

2016-09-05T14:14:50+00:00

Including machines__set_symbol_filter(), not used anymore.

Cc: Adrian Hunter 
Cc: David Ahern 
Cc: Jiri Olsa 
Cc: Masami Hiramatsu 
Cc: Namhyung Kim 
Cc: Wang Nan 
Link: http://lkml.kernel.org/n/tip-7o1qgmrpvzuis4a9f0t8mnri@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf s390: Fix 'start' address of module's map

2016-07-26T19:46:12+00:00

At present, when creating module's map, perf gets 'start' address by
parsing '/proc/modules', but it's the module base address, it isn't the
start address of the '.text' section.

In most arches, it's OK. But for s390, it places 'GOT' and 'PLT'
relocations before '.text' section. So there exists an offset between
module base address and '.text' section, which will incur wrong symbol
resolution for modules.

Fix this bug by getting 'start' address of module's map from parsing
'/sys/module/[module name]/sections/.text', not from '/proc/modules'.

Signed-off-by: Song Shan Gong 
Acked-by: Jiri Olsa 
Cc: Christian Borntraeger 
Cc: David Ahern 
Link: http://lkml.kernel.org/r/1469070651-6447-2-git-send-email-gongss@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo

perf machine: Destructors should accept NULL

2016-06-22T13:19:11+00:00

And do nothing, just like free(), to avoid having to test it in callers,
usually in error paths.

Cc: Adrian Hunter 
Cc: David Ahern 
Cc: Jiri Olsa 
Cc: Masami Hiramatsu 
Cc: Namhyung Kim 
Cc: Wang Nan 
Link: http://lkml.kernel.org/n/tip-q42gj3b3znhho9z1mrbo4jce@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

Merge tag 'perf-core-for-mingo-20160607' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/core

2016-06-08T07:34:15+00:00

Pull perf/core improvements and fixes from Arnaldo Carvalho de Melo:

User visible changes:

- Support cross unwinding, i.e. collecting '--call-graph dwarf' perf.data files
  in one machine and then doing analysis in another machine of a different
  hardware architecture. This enables, for instance, to do:

	perf record -a --call-graph dwarf

  on a x86-32 or aarch64 system and then do 'perf report' on it on a
  x86_64 workstation. (He Kuang)

- Fix crash in build_id_cache__kallsyms_path(), recent regression (Wang Nan)

Infrastructure changes:

- Make tools/lib/bpf use the IS_ERR return facility consistently and also stop
  using the _get_ term for non-reference count methods (Arnaldo Carvalho de Melo)

- 'perf config' refactorings (Taeung Song)

Signed-off-by: Arnaldo Carvalho de Melo 
Signed-off-by: Ingo Molnar