1. 07 12月, 2010 1 次提交
    • I
      perf hist: Better displaying of unresolved DSOs and symbols · 1437a30a
      Ian Munsie 提交于
      In the event that a DSO has not been identified, just print out [unknown]
      instead of the instruction pointer as we previously were doing, which is pretty
      meaningless for a shared object (at least to the users perspective).
      
      The IP we print out is fairly meaningless in general anyway - it's just one
      (the first) of the many addresses that were lumped together as unidentified,
      and could span many shared objects and symbols. In reality if we see this
      [unknown] output then the report -D output is going to be more useful anyway as
      we can see all the different address that it represents.
      
      If we are printing the symbols we are still going to see this IP in that column
      anyway since they shouldn't resolve either.
      
      This patch also changes the symbol address printouts so that they print out 0x
      before the address, are left aligned, and changes the %L format string (which
      relies on a glibc bug) to %ll.
      
      Before:
          74.11%    :3259               4a6c  [k]     4a6c
      After:
          74.11%    :3259  [unknown]          [k] 0x4a6c
      
      Cc: Frederic Weisbecker <fweisbec@gmail.com>
      Cc: Mike Galbraith <efault@gmx.de>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Stephane Eranian <eranian@google.com>
      LKML-Reference: <1291603026-11785-2-git-send-email-imunsie@au1.ibm.com>
      Signed-off-by: NIan Munsie <imunsie@au1.ibm.com>
      Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      1437a30a
  2. 05 12月, 2010 2 次提交
    • A
      perf tools: Ask for ID PERF_SAMPLE_ info on all PERF_RECORD_ events · 9c90a61c
      Arnaldo Carvalho de Melo 提交于
      So that we can use -T == --timestamp, asking for PERF_SAMPLE_TIME:
      
        $ perf record -aT
        $ perf report -D | grep PERF_RECORD_
        <SNIP>
         3   5951915425 0x47530 [0x58]: PERF_RECORD_SAMPLE(IP, 1): 16811/16811: 0xffffffff8138c1a2 period: 215979 cpu:3
         3   5952026879 0x47588 [0x90]: PERF_RECORD_SAMPLE(IP, 1): 16811/16811: 0xffffffff810cb480 period: 215979 cpu:3
         3   5952059959 0x47618 [0x38]: PERF_RECORD_FORK(6853:6853):(16811:16811)
         3   5952138878 0x47650 [0x78]: PERF_RECORD_SAMPLE(IP, 1): 16811/16811: 0xffffffff811bac35 period: 431478 cpu:3
         3   5952375068 0x476c8 [0x30]: PERF_RECORD_COMM: find:6853
         3   5952395923 0x476f8 [0x50]: PERF_RECORD_MMAP 6853/6853: [0x400000(0x25000) @ 0]: /usr/bin/find
         3   5952413756 0x47748 [0xa0]: PERF_RECORD_SAMPLE(IP, 1): 6853/6853: 0xffffffff810d080f period: 859332 cpu:3
         3   5952419837 0x477e8 [0x58]: PERF_RECORD_MMAP 6853/6853: [0x3f44600000(0x21d000) @ 0]: /lib64/ld-2.5.so
         3   5952437929 0x47840 [0x48]: PERF_RECORD_MMAP 6853/6853: [0x7fff7e1c9000(0x1000) @ 0x7fff7e1c9000]: [vdso]
         3   5952570127 0x47888 [0x58]: PERF_RECORD_MMAP 6853/6853: [0x3f46200000(0x218000) @ 0]: /lib64/libselinux.so.1
         3   5952623637 0x478e0 [0x58]: PERF_RECORD_MMAP 6853/6853: [0x3f44a00000(0x356000) @ 0]: /lib64/libc-2.5.so
         3   5952675720 0x47938 [0x58]: PERF_RECORD_MMAP 6853/6853: [0x3f44e00000(0x204000) @ 0]: /lib64/libdl-2.5.so
         3   5952710080 0x47990 [0x58]: PERF_RECORD_MMAP 6853/6853: [0x3f45a00000(0x246000) @ 0]: /lib64/libsepol.so.1
         3   5952847802 0x479e8 [0x58]: PERF_RECORD_SAMPLE(IP, 1): 6853/6853: 0xffffffff813897f0 period: 1142536 cpu:3
        <SNIP>
      
      First column is the cpu and the second the timestamp.
      
      That way we can investigate problems in the event stream.
      
      If the new perf binary is run on an older kernel, it will disable this feature
      automatically.
      Tested-by: NThomas Gleixner <tglx@linutronix.de>
      Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
      Acked-by: NIan Munsie <imunsie@au1.ibm.com>
      Acked-by: NThomas Gleixner <tglx@linutronix.de>
      Cc: Frédéric Weisbecker <fweisbec@gmail.com>
      Cc: Ian Munsie <imunsie@au1.ibm.com>
      Cc: Mike Galbraith <efault@gmx.de>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Stephane Eranian <eranian@google.com>
      LKML-Reference: <1291318772-30880-5-git-send-email-acme@infradead.org>
      Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      9c90a61c
    • A
      perf session: Parse sample earlier · 640c03ce
      Arnaldo Carvalho de Melo 提交于
      At perf_session__process_event, so that we reduce the number of lines in eache
      tool sample processing routine that now receives a sample_data pointer already
      parsed.
      
      This will also be useful in the next patch, where we'll allow sample the
      identity fields in MMAP, FORK, EXIT, etc, when it will be possible to see (cpu,
      timestamp) just after before every event.
      
      Also validate callchains in perf_session__process_event, i.e. as early as
      possible, and keep a counter of the number of events discarded due to invalid
      callchains, warning the user about it if it happens.
      
      There is an assumption that was kept that all events have the same sample_type,
      that will be dealt with in the future, when this preexisting limitation will be
      removed.
      Tested-by: NThomas Gleixner <tglx@linutronix.de>
      Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
      Acked-by: NIan Munsie <imunsie@au1.ibm.com>
      Acked-by: NThomas Gleixner <tglx@linutronix.de>
      Cc: Frédéric Weisbecker <fweisbec@gmail.com>
      Cc: Ian Munsie <imunsie@au1.ibm.com>
      Cc: Mike Galbraith <efault@gmx.de>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Stephane Eranian <eranian@google.com>
      LKML-Reference: <1291318772-30880-4-git-send-email-acme@infradead.org>
      Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      640c03ce
  3. 01 12月, 2010 11 次提交
  4. 27 11月, 2010 4 次提交
    • A
      perf tools: Fix lost and unknown events handling · 068ffaa8
      Arnaldo Carvalho de Melo 提交于
      Fix it by explaining what can be happening and giving the number of processed
      and lost events.
      
      Also holler if unknown events were found, that can be due to processing a
      perf.data file collected using a newer tool where newer events got added on
      reporting using an older perf tool, that or a bug, so ask for a report to be
      made.
      
      Works on both --tui and --stdio.
      Suggested-by: NThomas Gleixner <tglx@linutronix.de>
      Cc: Frédéric Weisbecker <fweisbec@gmail.com>
      Cc: Mike Galbraith <efault@gmx.de>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Stephane Eranian <eranian@google.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      LKML-Reference: <new-submission>
      Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      068ffaa8
    • I
      perf symbols: Correct final kernel map guesses · 9d1faba5
      Ian Munsie 提交于
      If a 32bit userspace perf is running on a 64bit kernel, the end of the final
      map in the kernel would incorrectly be set to 2^32-1 rather than 2^64-1.
      
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      LKML-Reference: <1290658375-10342-1-git-send-email-imunsie@au1.ibm.com>
      Signed-off-by: NIan Munsie <imunsie@au1.ibm.com>
      Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      9d1faba5
    • A
      perf events: Default to using event__process_lost · 37982ba0
      Arnaldo Carvalho de Melo 提交于
      Tool developers have to fill in a 'perf_event_ops' method table to
      specify how to handle each event, so far the ones that were not
      explicitely especified would get a stub that would just discard the
      event.
      
      Change that so that tool developers can get the lost event details and
      the total number of such events at the end of 'perf report -D' output.
      Suggested-by: NThomas Gleixner <tglx@linutronix.de>
      Cc: Frederic Weisbecker <fweisbec@gmail.com>
      Cc: Mike Galbraith <efault@gmx.de>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Stephane Eranian <eranian@google.com>
      CC: Thomas Gleixner <tglx@linutronix.de>
      Cc: Tom Zanussi <tzanussi@gmail.com>
      LKML-Reference: <new-submission>
      Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      37982ba0
    • A
      perf record: Add option to disable collecting build-ids · baa2f6ce
      Arnaldo Carvalho de Melo 提交于
      Collecting build-ids for long running sessions may take a long time
      because it needs to traverse the whole just collected perf.data stream
      of events, marking the DSOs that had hits and then looking for the
      .note.gnu.build-id ELF section.
      
      For things like the 'trace' tool that records and right away consumes
      the data on systems where its unlikely that the DSOs being monitored
      will change while 'trace' runs, it is desirable to remove build id
      collection, so add a -B/--no-buildid option to perf record to allow such
      use case.
      
      Longer term we'll avoid all this if we, at DSO load time, in the kernel,
      take advantage of this slow code path to collect the build-id and stash
      it somewhere, so that we can insert it in the PERF_RECORD_MMAP event.
      Reported-by: NThomas Gleixner <tglx@linutronix.de>
      Cc: Frederic Weisbecker <fweisbec@gmail.com>
      Cc: Mike Galbraith <efault@gmx.de>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Stephane Eranian <eranian@google.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Tom Zanussi <tzanussi@gmail.com>
      LKML-Reference: <new-submission>
      Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      baa2f6ce
  5. 26 11月, 2010 1 次提交
    • H
      perf bench: Add feature that measures the performance of the... · ea7872b9
      Hitoshi Mitake 提交于
      perf bench: Add feature that measures the performance of the arch/x86/lib/memcpy_64.S memcpy routines via 'perf bench mem'
      
      This patch ports arch/x86/lib/memcpy_64.S to perf bench mem
      memcpy for benchmarking memcpy() in userland with tricky and
      dirty way.
      
      util/include/asm/cpufeature.h, util/include/asm/dwarf2.h, and
      util/include/linux/linkage.h are mostly dummy files with small
      wrappers, so that we are able to include memcpy_64.S
      unmodified.
      Signed-off-by: NHitoshi Mitake <mitake@dcl.info.waseda.ac.jp>
      Cc: h.mitake@gmail.com
      Cc: Miao Xie <miaox@cn.fujitsu.com>
      Cc: Ma Ling <ling.ma@intel.com>
      Cc: Zhao Yakui <yakui.zhao@intel.com>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Frederic Weisbecker <fweisbec@gmail.com>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: Andi Kleen <andi@firstfloor.org>
      LKML-Reference: <1290668693-27068-2-git-send-email-mitake@dcl.info.waseda.ac.jp>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      ea7872b9
  6. 24 11月, 2010 1 次提交
    • R
      perf symbols: Remove incorrect open-coded container_of() · 02a9d037
      Rabin Vincent 提交于
      At least on ARM, padding is inserted between rb_node and sym in struct
      symbol_name_rb_node, causing "((void *)sym) - sizeof(struct rb_node)" to
      point inside rb_node rather than to the symbol_name_rb_node.  Fix this
      by converting the code to use container_of().
      
      Cc: Ian Munsie <imunsie@au1.ibm.com>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Ming Lei <tom.leiming@gmail.com>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Tom Zanussi <tzanussi@gmail.com>
      LKML-Reference: <20101123163106.GA25677@debian>
      Signed-off-by: NRabin Vincent <rabin@rab.in>
      Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      02a9d037
  7. 20 11月, 2010 1 次提交
    • R
      perf tools: Remove hardcoded include paths for elfutils · a7112397
      Robert Morell 提交于
      This change removes the use of hardcoded absolute "/usr/include/elfutils" paths
      from the perf build.  The problem with hardcoded paths is that it prevents them
      from being overridden by $prefix or by -I in CFLAGS (e.g., for cross-compiling
      purposes).
      
      Instead, just include the "elfutils/" subdirectory as a relative path when
      files are needed from that directory.
      
      Tested by building perf:
      - Cross-compiled for ARM on x86_64
      - Built natively on x86_64
      - Built on x86_64 with /usr/include/elfutils moved to another location
        and manually included in CFLAGS
      Acked-by: NMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
      LKML-Reference: <1289945793-31441-1-git-send-email-rmorell@nvidia.com>
      Signed-off-by: NRobert Morell <rmorell@nvidia.com>
      Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      a7112397
  8. 17 11月, 2010 1 次提交
  9. 10 11月, 2010 1 次提交
  10. 27 10月, 2010 1 次提交
  11. 24 10月, 2010 1 次提交
  12. 23 10月, 2010 1 次提交
    • A
      perf tools: Remove direct slang.h include · 8bfb5e7d
      Arnaldo Carvalho de Melo 提交于
      We wrap it in libslang.h because we need to deal with older slang release
      where HAVE_LONG_LONG is referenced as:
      
      So we need to define it.
      
      Noticed when rebuilding the perf tools on a RHEL5 machine.
      
      Cc: Frédéric Weisbecker <fweisbec@gmail.com>
      Cc: Mike Galbraith <efault@gmx.de>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Stephane Eranian <eranian@google.com>
      LKML-Reference: <new-submission>
      Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      8bfb5e7d
  13. 22 10月, 2010 7 次提交
    • M
      perf probe: Add basic module support · 469b9b88
      Masami Hiramatsu 提交于
      Add basic module probe support on perf probe. This introduces "--module
      <MODNAME>" option to perf probe for putting probes and showing lines and
      variables in the given module.
      
      Currently, this supports only probing on running modules.  Supporting off-line
      module probing is the next step.
      
      e.g.)
      [show lines]
       # ./perf probe --module drm -L drm_vblank_info
      <drm_vblank_info:0>
            0  int drm_vblank_info(struct seq_file *m, void *data)
            1  {
                      struct drm_info_node *node = (struct drm_info_node *) m->private
            3         struct drm_device *dev = node->minor->dev;
       ...
      [show vars]
       # ./perf probe --module drm -V drm_vblank_info:3
      Available variables at drm_vblank_info:3
              @<drm_vblank_info+20>
                      (unknown_type)  data
                      struct drm_info_node*   node
                      struct seq_file*        m
      [put a probe]
       # ./perf probe --module drm drm_vblank_info:3 node m
      Add new event:
        probe:drm_vblank_info (on drm_vblank_info:3 with node m)
      
      You can now use it on all perf tools, such as:
      
              perf record -e probe:drm_vblank_info -aR sleep 1
      [list probes]
       # ./perf probe -l
      probe:drm_vblank_info (on drm_vblank_info:3@drivers/gpu/drm/drm_info.c with ...
      
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Frederic Weisbecker <fweisbec@gmail.com>
      LKML-Reference: <20101021101341.3542.71638.stgit@ltc236.sdl.hitachi.co.jp>
      Signed-off-by: NMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
      Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      469b9b88
    • M
      perf probe: Show accessible global variables · fb8c5a56
      Masami Hiramatsu 提交于
      Add --externs for allowing --vars to show accessible global (externally
      defined) variables from a given probe point too.
      
      This will give you a hint which globals can be accessible from the probe point.
      
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Frederic Weisbecker <fweisbec@gmail.com>
      LKML-Reference: <20101021101335.3542.31003.stgit@ltc236.sdl.hitachi.co.jp>
      Signed-off-by: NMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
      Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      fb8c5a56
    • M
      perf probe: Function style fix · c82ec0a2
      Masami Hiramatsu 提交于
      Just change the order of function arguments for ease of read; moving optional
      bool flag to the last.
      
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Frederic Weisbecker <fweisbec@gmail.com>
      LKML-Reference: <20101021101329.3542.51200.stgit@ltc236.sdl.hitachi.co.jp>
      Signed-off-by: NMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
      Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      c82ec0a2
    • M
      perf probe: Show accessible local variables · cf6eb489
      Masami Hiramatsu 提交于
      Add -V (--vars) option for listing accessible local variables at given probe
      point. This will help finding which local variables are available for event
      arguments.
      
      e.g.)
       # perf probe -V call_timer_fn:23
       Available variables at call_timer_fn:23
               @<run_timer_softirq+345>
                       function_type*  fn
                       int     preempt_count
                       long unsigned int       data
                       struct list_head        work_list
                       struct list_head*       head
                       struct timer_list*      timer
                       struct tvec_base*       base
      
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Frederic Weisbecker <fweisbec@gmail.com>
      LKML-Reference: <20101021101323.3542.40282.stgit@ltc236.sdl.hitachi.co.jp>
      Signed-off-by: NMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
      Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      cf6eb489
    • M
      perf probe: Support global variables · 632941c4
      Masami Hiramatsu 提交于
      Allow users to set external defined global variables as event arguments (e.g.
      jiffies).
      
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Ingo Molnar <mingo@elte.hu>
      LKML-Reference: <20101021101316.3542.1999.stgit@ltc236.sdl.hitachi.co.jp>
      Signed-off-by: NMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
      Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      632941c4
    • M
      perf probe: Fix local variable searching loop · 378eeaad
      Masami Hiramatsu 提交于
      Fix to check the die's address and search into the die only if it has given
      address.
      
      This will avoid finding wrong variables in wrong basic block.
      
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Ingo Molnar <mingo@elte.hu>
      LKML-Reference: <20101021101309.3542.46434.stgit@ltc236.sdl.hitachi.co.jp>
      Signed-off-by: NMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
      Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      378eeaad
    • M
      perf probe: Fix type searching · 4046b8bb
      Masami Hiramatsu 提交于
      Fix to get the actual type die of variables by using dwarf_attr_integrate()
      which gets attribute from die even if the type die is connected by
      DW_AT_abstract_origin.
      
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Ingo Molnar <mingo@elte.hu>
      LKML-Reference: <20101021101302.3542.38549.stgit@ltc236.sdl.hitachi.co.jp>
      Signed-off-by: NMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
      Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      4046b8bb
  14. 04 10月, 2010 2 次提交
  15. 13 9月, 2010 1 次提交
    • A
      perf ui browser: Don't use windows, slang is enough · 469917ce
      Arnaldo Carvalho de Melo 提交于
      They are useless and take away precious columns and lines, so stop using
      windows.
      
      One more step in removing newt code, that after all is not being useful
      at all for the coalescing TUI model in perf.
      Suggested-by: NChristoph Hellwig <hch@infradead.org>
      Cc: Christoph Hellwig <hch@infradead.org>
      Cc: Frederic Weisbecker <fweisbec@gmail.com>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Mike Galbraith <efault@gmx.de>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Stephane Eranian <eranian@google.com>
      Cc: Tom Zanussi <tzanussi@gmail.com>
      LKML-Reference: <20100822082003.GB7365@infradead.org>
      Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      469917ce
  16. 10 9月, 2010 1 次提交
  17. 08 9月, 2010 2 次提交
  18. 27 8月, 2010 1 次提交
    • F
      perf: Initialize callchains roots's childen hits · 5225c458
      Frederic Weisbecker 提交于
      Each histogram entry has a callchain root that stores the
      callchain samples. However we forgot to initialize the
      tracking of children hits of these roots, which then got
      random values on their creation.
      
      The root children hits is multiplied by the minimum percentage
      of hits provided by the user, and the result becomes the minimum
      hits expected from children branches. If the random value due
      to the uninitialization is big enough, then this minimum number
      of hits can be huge and eventually filter every children branches.
      
      The end result was invisible callchains. All we need to
      fix this is to initialize the children hits of the root.
      Reported-by: NChristoph Hellwig <hch@infradead.org>
      Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: 2.6.32.x-2.6.35.y <stable@kernel.org>
      5225c458