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  1. 02 12月, 2014 1 次提交
    • A
      perf callchain: Support handling complete branch stacks as histograms · 8b7bad58
      由 Andi Kleen 提交于 
      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: NAndi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/1415844328-4884-3-git-send-email-andi@firstfloor.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      8b7bad58
  3. 25 11月, 2014 1 次提交
  5. 19 11月, 2014 2 次提交
  7. 05 11月, 2014 2 次提交
    • N
      perf tools: Make vmlinux short name more like kallsyms short name · 96d78059
      由 Namhyung Kim 提交于 
      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: NNamhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1415063674-17206-9-git-send-email-namhyung@kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      96d78059
    • N
      perf tools: Fix build-id matching on vmlinux · b837a8bd
      由 Namhyung Kim 提交于 
      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 0a7e6d1b ("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: NNamhyung Kim <namhyung@kernel.org>
Acked-by: NIngo Molnar <mingo@kernel.org>
Link: http://lkml.kernel.org/r/20140924073356.GB1962@gmail.com
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1415063674-17206-8-git-send-email-namhyung@kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      b837a8bd
  9. 04 11月, 2014 1 次提交
  11. 29 10月, 2014 4 次提交
  13. 15 10月, 2014 1 次提交
    • A
      perf machine: Add missing dsos->root rbtree root initialization · e167f995
      由 Arnaldo Carvalho de Melo 提交于 
      A segfault happens on 'perf test hists_link' because we end up using a
struct machines on the stack, and then machines__init() was not
initializing the newly introduced rb_root, just the existing list_head.

When we introduced struct dsos, to group the two ways to store dsos,
i.e. the linked list and the rbtree, we didn't turned the initialization
done in:

	machines__init(machines->host) ->
		machine__init() ->
			INIT_LIST_HEAD

into a dsos__init() to keep on initializing the list_head but _as well_
initializing the rb_root, oops.

All worked because outside perf-test we probably zalloc the whole thing
which ends up initializing it in to NULL.

So the problem looks contained to 'perf test' that uses it on stack,
etc.
Reported-by: NJiri Olsa <jolsa@redhat.com>
Acked-by: Waiman Long <Waiman.Long@hp.com>,
Cc: Adrian Hunter <adrian.hunter@intel.com>,
Cc: Don Zickus <dzickus@redhat.com>
Cc: Douglas Hatch <doug.hatch@hp.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Scott J Norton <scott.norton@hp.com>
Cc: Waiman Long <Waiman.Long@hp.com>,
Link: http://lkml.kernel.org/r/20141014180353.GF3198@kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      e167f995
  15. 02 10月, 2014 1 次提交
    • W
      perf symbols: Improve DSO long names lookup speed with rbtree · 4598a0a6
      由 Waiman Long 提交于 
      With workload that spawns and destroys many threads and processes, it
was found that perf-mem could took a long time to post-process the perf
data after the target workload had completed its operation.

The performance bottleneck was found to be the lookup and insertion of
the new DSO structures (thousands of them in this case).

In a dual-socket Ivy-Bridge E7-4890 v2 machine (30-core, 60-thread), the
perf profile below shows what perf was doing after the profiled AIM7
shared workload completed:

-     83.94%  perf  libc-2.11.3.so     [.] __strcmp_sse42
   - __strcmp_sse42
      - 99.82% map__new
           machine__process_mmap_event
           perf_session_deliver_event
           perf_session__process_event
           __perf_session__process_events
           cmd_record
           cmd_mem
           run_builtin
           main
           __libc_start_main
-     13.17%  perf  perf               [.] __dsos__findnew
     __dsos__findnew
     map__new
     machine__process_mmap_event
     perf_session_deliver_event
     perf_session__process_event
     __perf_session__process_events
     cmd_record
     cmd_mem
     run_builtin
     main
     __libc_start_main

So about 97% of CPU times were spent in the map__new() function trying
to insert new DSO entry into the DSO linked list. The whole
post-processing step took about 9 minutes.

The DSO structures are currently searched linearly. So the total
processing time will be proportional to n^2.

To overcome this performance problem, the DSO code is modified to also
put the DSO structures in a RB tree sorted by its long name in
additional to being in a simple linked list. With this change, the
processing time will become proportional to n*log(n) which will be much
quicker for large n. However, the short name will still be searched
using the old linear searching method.  With that patch in place, the
same perf-mem post-processing step took less than 30 seconds to
complete.
Signed-off-by: NWaiman Long <Waiman.Long@hp.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Douglas Hatch <doug.hatch@hp.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Scott J Norton <scott.norton@hp.com>
Link: http://lkml.kernel.org/r/1412098575-27863-3-git-send-email-Waiman.Long@hp.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      4598a0a6
  17. 30 9月, 2014 1 次提交
    • W
      perf symbols: Encapsulate dsos list head into struct dsos · 8fa7d87f
      由 Waiman Long 提交于 
      This is a precursor patch to enable long name searching of DSOs using
a rbtree.

In this patch, a new dsos structure is created which contains only a
list head structure for the moment.

The new dsos structure is used, in turn, in the machine structure for
the user_dsos and kernel_dsos fields.

Only the following 3 dsos functions are modified to accept the new dsos
structure parameter instead of list_head:

 - dsos__add()
 - dsos__find()
 - __dsos__findnew()
Signed-off-by: NWaiman Long <Waiman.Long@hp.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Douglas Hatch <doug.hatch@hp.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Scott J Norton <scott.norton@hp.com>
Link: http://lkml.kernel.org/r/1412021249-19201-2-git-send-email-Waiman.Long@hp.com
[ Move struct dsos to dso.h to reduce the dso methods depends on machine.h ]
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      8fa7d87f
  19. 23 8月, 2014 3 次提交
  21. 14 8月, 2014 2 次提交
  23. 24 7月, 2014 3 次提交
  25. 23 7月, 2014 1 次提交
  27. 17 7月, 2014 3 次提交
  29. 27 6月, 2014 1 次提交
    • S
      perf tools powerpc: Adjust callchain based on DWARF debug info · a60335ba
      由 Sukadev Bhattiprolu 提交于 
      When saving the callchain on Power, the kernel conservatively saves excess
entries in the callchain. A few of these entries are needed in some cases
but not others. We should use the DWARF debug information to determine
when the entries are  needed.

Eg: the value in the link register (LR) is needed only when it holds the
return address of a function. At other times it must be ignored.

If the unnecessary entries are not ignored, we end up with duplicate arcs
in the call-graphs.

Use the DWARF debug information to determine if any callchain entries
should be ignored when building call-graphs.

Callgraph before the patch:

    14.67%          2234  sprintft  libc-2.18.so       [.] __random
            |
            --- __random
               |
               |--61.12%-- __random
               |          |
               |          |--97.15%-- rand
               |          |          do_my_sprintf
               |          |          main
               |          |          generic_start_main.isra.0
               |          |          __libc_start_main
               |          |          0x0
               |          |
               |           --2.85%-- do_my_sprintf
               |                     main
               |                     generic_start_main.isra.0
               |                     __libc_start_main
               |                     0x0
               |
                --38.88%-- rand
                          |
                          |--94.01%-- rand
                          |          do_my_sprintf
                          |          main
                          |          generic_start_main.isra.0
                          |          __libc_start_main
                          |          0x0
                          |
                           --5.99%-- do_my_sprintf
                                     main
                                     generic_start_main.isra.0
                                     __libc_start_main
                                     0x0

Callgraph after the patch:

    14.67%          2234  sprintft  libc-2.18.so       [.] __random
            |
            --- __random
               |
               |--95.93%-- rand
               |          do_my_sprintf
               |          main
               |          generic_start_main.isra.0
               |          __libc_start_main
               |          0x0
               |
                --4.07%-- do_my_sprintf
                          main
                          generic_start_main.isra.0
                          __libc_start_main
                          0x0

TODO:	For split-debug info objects like glibc, we can only determine
	the call-frame-address only when both .eh_frame and .debug_info
	sections are available. We should be able to determin the CFA
	even without the .eh_frame section.

Fix suggested by Anton Blanchard.

Thanks to valuable input on DWARF debug information from Ulrich Weigand.
Reported-by: NMaynard Johnson <maynard@us.ibm.com>
Tested-by: NMaynard Johnson <maynard@us.ibm.com>
Signed-off-by: NSukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/20140625154903.GA29607@us.ibm.comSigned-off-by: NJiri Olsa <jolsa@kernel.org>
      a60335ba
  31. 20 6月, 2014 1 次提交
  33. 09 6月, 2014 1 次提交
  35. 30 4月, 2014 1 次提交
  37. 28 4月, 2014 1 次提交
  39. 19 3月, 2014 2 次提交
  41. 15 3月, 2014 2 次提交
  43. 10 3月, 2014 1 次提交
  45. 18 2月, 2014 3 次提交
  47. 01 2月, 2014 1 次提交