linux-stable.git/tools/perf/util/machine.c, branch linux-3.19.y

perf machine: Fix machinefindnew_thread() error path

2015-01-16T20:49:28+00:00

When thread__init_map_groups() fails, a new thread should be removed
from the rbtree since it's gonna be freed.  Also update last match cache
only if the function succeeded.

Reported-by: David Ahern 
Signed-off-by: Namhyung Kim 
Acked-by: Jiri Olsa 
Cc: David Ahern 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1420763892-15535-1-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf callchain: Move cpumode resolve code to add_callchain_ip

2014-12-09T13:06:29+00:00

Using flag to distinguish between branch_history and normal callchain.

Move the cpumode to add_callchain_ip function.

No change in behavior.

Signed-off-by: Kan Liang 
Acked-by: Jiri Olsa 
Cc: Andi Kleen 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Link: http://lkml.kernel.org/r/1417532814-26208-3-git-send-email-kan.liang@intel.com
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 tools: Fix segfault due to invalid kernel dso access

2014-11-24T21:03:48+00:00

Jiri reported that the commit 96d78059d6d9 ("perf tools: Make vmlinux
short name more like kallsyms short name") segfaults on perf script.

When processing kernel mmap event, it should access the 'kernel'
variable as sometimes it cannot find a matching dso from build-id table
so 'dso' might be invalid.

Reported-by: Jiri Olsa 
Tested-by: Jiri Olsa 
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 
Link: http://lkml.kernel.org/r/1416285028-30572-1-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf callchain: Use al.addr to set up call chain

2014-11-19T15:33:47+00:00

Use the relative address, this makes get_srcline work correctly in the
end.

Signed-off-by: Andi Kleen 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Link: http://lkml.kernel.org/r/1415844328-4884-4-git-send-email-andi@firstfloor.org
Signed-off-by: Arnaldo Carvalho de Melo

perf callchain: Factor out adding new call chain entries

2014-11-19T15:33:47+00:00

Move the code to resolve and add a new callchain entry into a new
add_callchain_ip function. This will be used in the next patches to add
LBRs too.

No change in behavior.

Signed-off-by: Andi Kleen 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Link: http://lkml.kernel.org/r/1415844328-4884-2-git-send-email-andi@firstfloor.org
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Make vmlinux short name more like kallsyms short name

2014-11-05T13:14:09+00:00

The previous patch changed kernel dso name from '[kernel.kallsyms]' to
vmlinux.  However it might add confusion to old users accustomed to the
old name.  So change the short name to '[kernel.vmlinux]' to reduce such
confusion.

Before:
  # Overhead  Command         Shared Object            Symbol
  # ........  ..............  .......................  ...............................
  #
       9.83%  swapper         vmlinux                  [k] intel_idle
       4.10%  awk             libc-2.20.so             [.] __strcmp_sse2
       1.86%  sed             libc-2.20.so             [.] __strcmp_sse2
       1.78%  netctl-auto     libc-2.20.so             [.] __strcmp_sse2
       1.23%  netctl-auto     libc-2.20.so             [.] __mbrtowc
       1.21%  firefox         libxul.so                [.] 0x00000000024b62bd
       1.20%  swapper         vmlinux                  [k] cpuidle_enter_state
       1.03%  sleep           vmlinux                  [k] copy_user_generic_unrolled

After:
  # Overhead  Command         Shared Object            Symbol
  # ........  ..............  .......................  ...............................
  #
       9.83%  swapper         [kernel.vmlinux]         [k] intel_idle
       4.10%  awk             libc-2.20.so             [.] __strcmp_sse2
       1.86%  sed             libc-2.20.so             [.] __strcmp_sse2
       1.78%  netctl-auto     libc-2.20.so             [.] __strcmp_sse2
       1.23%  netctl-auto     libc-2.20.so             [.] __mbrtowc
       1.21%  firefox         libxul.so                [.] 0x00000000024b62bd
       1.20%  swapper         [kernel.vmlinux]         [k] cpuidle_enter_state
       1.03%  sleep           [kernel.vmlinux]         [k] copy_user_generic_unrolled

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/1415063674-17206-9-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Fix build-id matching on vmlinux

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

There's a problem on finding correct kernel symbols when perf report
runs on a different kernel.  Although a part of the problem was solved
by the prior commit 0a7e6d1b6844 ("perf tools: Check recorded kernel
version when finding vmlinux"), there's a remaining problem still.

When perf records samples, it synthesizes the kernel map using
machine__mmap_name() and ref_reloc_sym like "[kernel.kallsyms]_text".
You can easily see it using 'perf report -D' command.

After finishing record, it goes through the recorded events to find
maps/dsos actually used.  And then record build-id info of them.

During this process, it needs to load symbols in a dso and it'd call
dso__load_vmlinux_path() since the default value of the symbol_conf.
try_vmlinux_path is true.  However it changes dso->long_name to a real
path of the vmlinux file (e.g. /lib/modules/3.16.4/build/vmlinux) if one
is running on a custom kernel.

It resulted in that perf report reads the build-id of the vmlinux, but
cannot use it since it only knows about the [kernel.kallsyms] map.  It
then falls back to possible vmlinux paths by using the recorded kernel
version (in case of a recent version) or a running kernel silently.

Even with the recent tools, this still has a possibility of breaking
the result.  As the build directory is a symbolic link, if one built a
new kernel in the same directory with different source/config, the old
link to vmlinux will point the new file.  So it's absolutely needed to
use build-id when finding a kernel image.

In this patch, it's now changed to try to search a kernel dso in the
existing dso list which was constructed during build-id table parsing
so it'll always have a build-id.  If not found, search "[kernel.kallsyms]".

Before:

  $ perf report
  # Children      Self  Command  Shared Object      Symbol
  # ........  ........  .......  .................  ...............................
  #
      72.15%     0.00%  swapper  [kernel.kallsyms]  [k] set_curr_task_rt
      72.15%     0.00%  swapper  [kernel.kallsyms]  [k] native_calibrate_tsc
      72.15%     0.00%  swapper  [kernel.kallsyms]  [k] tsc_refine_calibration_work
      71.87%    71.87%  swapper  [kernel.kallsyms]  [k] module_finalize
   ...

After (for the same perf.data):

      72.15%     0.00%  swapper  vmlinux  [k] cpu_startup_entry
      72.15%     0.00%  swapper  vmlinux  [k] arch_cpu_idle
      72.15%     0.00%  swapper  vmlinux  [k] default_idle
      71.87%    71.87%  swapper  vmlinux  [k] native_safe_halt
   ...

Signed-off-by: Namhyung Kim 
Acked-by: Ingo Molnar 
Link: http://lkml.kernel.org/r/20140924073356.GB1962@gmail.com
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/1415063674-17206-8-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf symbols: Preparation for compressed kernel module support

2014-11-04T13:15:53+00:00

This patch adds basic support to handle compressed kernel module as some
distro (such as Archlinux) carries on it now.  The actual work using
compression library will be added later.

Signed-off-by: Namhyung Kim 
Acked-by: Jiri Olsa 
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/1415063674-17206-2-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf callchains: Use thread->mg->machine

2014-10-29T12:32:46+00:00

The unwind__get_entries() already receives the thread parameter, from where it can
obtain the matching machine structure, shorten the signature.

Cc: Adrian Hunter 
Cc: Borislav Petkov 
Cc: David Ahern 
Cc: Don Zickus 
Cc: Frederic Weisbecker 
Cc: Jean Pihet 
Cc: Jiri Olsa 
Cc: Mike Galbraith 
Cc: Namhyung Kim 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Link: http://lkml.kernel.org/n/tip-isjc6bm8mv4612mhi6af64go@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo