linux-toradex.git/tools/perf/util/symbol.h, branch v4.1

perf tools: Add pid/tid filtering to report and script commands

2015-03-24T16:02:46+00:00

The 'record' and 'top' tools already allow a user to specify a CSV of
pids and/or tids of tasks to collect data.

Add those options to the 'report' and 'script' analysis commands to only
consider samples related to the given pids/tids.

This is also inline with the existing comm option.

Signed-off-by: David Ahern 
Cc: Adrian Hunter 
Cc: Frederic Weisbecker 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Stephane Eranian 
Link: http://lkml.kernel.org/r/1427212361-7066-1-git-send-email-dsahern@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo

perf symbols: Allow symbol alias when loading map for symbol name

2015-03-12T15:39:54+00:00

When perf probe tries to add a probe in a binary using symbol name, it
sometimes failed since some symbols were discard during loading dso.

When it resolves an address to symbol, it'd be better to have just one
symbol at given address.  But for finding address from symbol, it'd be
better to keep all names (including aliases).

So allow tools to state that they want to allow aliases via
symbol_conf.allow_aliases.

Signed-off-by: Namhyung Kim 
Acked-by: Masami Hiramatsu 
Cc: David Ahern 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: Naohiro Aota 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/20150306073127.6904.3232.stgit@localhost.localdomain
[ Original patch passwd allow_alias to many functions, use symbol_conf.allow_aliases instead ]
Signed-off-by: Arnaldo Carvalho de Melo

perf symbols: Introduce method to iterate symbols ordered by name

2015-01-21T13:05:54+00:00

Given a symbol, go to the next entry in a rbtree sorted by symbol name.

Cc: David Ahern 
Cc: Jiri Olsa 
Cc: Masami Hiramatsu 
Link: http://lkml.kernel.org/n/tip-aq210drxprnu2so4dye5xa3j@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf callchain: Support handling complete branch stacks as histograms

2014-12-01T23:00:31+00:00

Currently branch stacks can be only shown as edge histograms for
individual branches. I never found this display particularly useful.

This implements an alternative mode that creates histograms over
complete branch traces, instead of individual branches, similar to how
normal callgraphs are handled. This is done by putting it in front of
the normal callgraph and then using the normal callgraph histogram
infrastructure to unify them.

This way in complex functions we can understand the control flow that
lead to a particular sample, and may even see some control flow in the
caller for short functions.

Example (simplified, of course for such simple code this is usually not
needed), please run this after the whole patchkit is in, as at this
point in the patch order there is no --branch-history, that will be
added in a patch after this one:

tcall.c:

volatile a = 10000, b = 100000, c;

__attribute__((noinline)) f2()
{
	c = a / b;
}

__attribute__((noinline)) f1()
{
	f2();
	f2();
}
main()
{
	int i;
	for (i = 0; i < 1000000; i++)
		f1();
}

% perf record -b -g ./tsrc/tcall
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.044 MB perf.data (~1923 samples) ]
% perf report --no-children --branch-history
...
    54.91%  tcall.c:6  [.] f2                      tcall
            |
            |--65.53%-- f2 tcall.c:5
            |          |
            |          |--70.83%-- f1 tcall.c:11
            |          |          f1 tcall.c:10
            |          |          main tcall.c:18
            |          |          main tcall.c:18
            |          |          main tcall.c:17
            |          |          main tcall.c:17
            |          |          f1 tcall.c:13
            |          |          f1 tcall.c:13
            |          |          f2 tcall.c:7
            |          |          f2 tcall.c:5
            |          |          f1 tcall.c:12
            |          |          f1 tcall.c:12
            |          |          f2 tcall.c:7
            |          |          f2 tcall.c:5
            |          |          f1 tcall.c:11
            |          |
            |           --29.17%-- f1 tcall.c:12
            |                     f1 tcall.c:12
            |                     f2 tcall.c:7
            |                     f2 tcall.c:5
            |                     f1 tcall.c:11
            |                     f1 tcall.c:10
            |                     main tcall.c:18
            |                     main tcall.c:18
            |                     main tcall.c:17
            |                     main tcall.c:17
            |                     f1 tcall.c:13
            |                     f1 tcall.c:13
            |                     f2 tcall.c:7
            |                     f2 tcall.c:5
            |                     f1 tcall.c:12

The default output is unchanged.

This is only implemented in perf report, no change to record or anywhere
else.

This adds the basic code to report:

- add a new "branch" option to the -g option parser to enable this mode
- when the flag is set include the LBR into the callstack in machine.c.

The rest of the history code is unchanged and doesn't know the
difference between LBR entry and normal call entry.

- detect overlaps with the callchain
- remove small loop duplicates in the LBR

Current limitations:

- The LBR flags (mispredict etc.) are not shown in the history
and LBR entries have no special marker.
- It would be nice if annotate marked the LBR entries somehow
(e.g. with arrows)

v2: Various fixes.
v3: Merge further patches into this one. Fix white space.
v4: Improve manpage. Address review feedback.
v5: Rename functions. Better error message without -g. Fix crash without
    -b.
v6: Rebase
v7: Rebase. Use NO_ENTRY in memset.
v8: Port to latest tip. Move add_callchain_ip to separate
    patch. Skip initial entries in callchain. Minor cleanups.

Signed-off-by: Andi Kleen 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Link: http://lkml.kernel.org/r/1415844328-4884-3-git-send-email-andi@firstfloor.org
Signed-off-by: Arnaldo Carvalho de Melo

perf symbols: Move bfd_demangle stubbing to its only user

2014-11-24T21:03:47+00:00

We need to define bfd_demangle() to either a wrapper for
cplus_demangle() or to a stub when NO_DEMANGLE is defined.

That is at odds with using bfd.h for some other reason, as it defines
bfd_demangle() and then if code that wants to use symbol.h, where the
above stubbing/wrapping is done, and bfd.h for other reasons, we end up
with a build error where bfd_demangle() is found to be redefined.

Avoid that by moving the stubbing/wrapping to symbol-elf.c, that is the
only user of such function. If we ever get to a point where there are
more valid users, we can then introduce a header for that.

Cc: Adrian Hunter 
Cc: Andi Kleen 
Cc: Borislav Petkov 
Cc: David Ahern 
Cc: Don Zickus 
Cc: Frederic Weisbecker 
Cc: Jiri Olsa 
Cc: Mike Galbraith 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Link: http://lkml.kernel.org/n/tip-6wzjpe2fy9xtgchshulixlzw@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf record: Do not save pathname in ./debug/.build-id directory for vmlinux

2014-11-05T13:14:08+00:00

When perf record finishes a session, it pre-processes samples in order
to write build-id info from DSOs that had samples.

During this process it'll call map__load() for the kernel map, and it
ends up calling dso__load_vmlinux_path() which replaces dso->long_name.

But this function checks kernel's build-id before searching vmlinux path
so it'll end up with a cryptic name, the pathname for the entry in the
~/.debug cache, which can be confusing to users.

This patch adds a flag to skip the build-id check during record, so
that it'll have the original vmlinux path for the kernel dso->long_name,
not the entry in the ~/.debug cache.

Before:
  # perf record -va sleep 3
  mmap size 528384B
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.196 MB perf.data (~8545 samples) ]
  Looking at the vmlinux_path (7 entries long)
  Using /home/namhyung/.debug/.build-id/f0/6e17aa50adf4d00b88925e03775de107611551 for symbols

After:
  # perf record -va sleep 3
  mmap size 528384B
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.193 MB perf.data (~8432 samples) ]
  Looking at the vmlinux_path (7 entries long)
  Using /lib/modules/3.16.4-1-ARCH/build/vmlinux for symbols

Signed-off-by: Namhyung Kim 
Cc: Adrian Hunter 
Cc: David Ahern 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Link: http://lkml.kernel.org/r/1415063674-17206-7-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf symbols: Make sym->end be the first address after the symbol range

2014-10-14T20:50:58+00:00

To follow vm_area_struct->vm_end convention.

By adhering to the convention that ->end is the first address outside
the symbol's range we can do things like:

	sym->end = start + len;
	len = sym->end - sym->start;

This is also now the convention used for struct map->end, fixing some
off-by-one bugs.

Cc: Adrian Hunter 
Cc: Chuck Ebbert 
Cc: David Ahern 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Link: http://lkml.kernel.org/n/tip-agomujr7tuqaq6lu7kr6z7h6@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Disable kernel symbol demangling by default

2014-09-17T20:08:09+00:00

Some Linux symbols (for example __vt_event_wait) are interpreted by the
demangler as C++ mangled names, which of course they aren't.

Disable kernel symbol demangling by default to avoid this, and allow
enabling it with a new option --demangle-kernel for those who wish it.

Reported-by: Jiri Olsa 
Signed-off-by: Avi Kivity 
Acked-by: Jiri Olsa 
Cc: Jiri Olsa 
Link: http://lkml.kernel.org/r/1410581705-26968-1-git-send-email-avi@cloudius-systems.com
Signed-off-by: Arnaldo Carvalho de Melo

perf symbols: Don't demangle parameters and such by default

2014-08-13T20:39:25+00:00

Some C++ symbols have very long name and they make column length longer.
Most of them are about parameters including templates and we can ignore
such info most of time IMHO.

This patch passes DMGL_NO_OPTS by default when calling bfd_demangle().
One can still see full symbols with -v/--verbose option.

before:
  JS_CallFunctionValue(JSContext*, JSObject*, JS::Value, unsigned int, JS::Value*, JS::Value*)

after:
  JS_CallFunctionValue

Signed-off-by: Namhyung Kim 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1406785662-5534-9-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Check recorded kernel version when finding vmlinux

2014-08-13T19:42:21+00:00

Currently vmlinux_path__init() only tries to find vmlinux file from
current directory, /boot and some canonical directories with version
number of the running kernel.  This can be a problem when reporting old
data recorded on a kernel version not running currently.

We can use --symfs option for this but it's annoying for user to do it
always.  As we already have the info in the perf.data file, it can be
changed to use it for the search automatically.

Before:

  $ perf report
  ...
  # Samples: 4K of event 'cpu-clock'
  # Event count (approx.): 1067250000
  #
  # Overhead  Command     Shared Object      Symbol
  # ........  ..........  .................  ..............................
      71.87%     swapper  [kernel.kallsyms]  [k] recover_probed_instruction

After:

  # Overhead  Command     Shared Object      Symbol
  # ........  ..........  .................  ....................
      71.87%     swapper  [kernel.kallsyms]  [k] native_safe_halt

This requires to change signature of symbol__init() to receive struct
perf_session_env *.

Reported-by: Minchan Kim 
Signed-off-by: Namhyung Kim 
Cc: Adrian Hunter 
Cc: David Ahern 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: Masami Hiramatsu 
Cc: Minchan Kim 
Cc: Namhyung Kim 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Link: http://lkml.kernel.org/r/1407825645-24586-14-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo