1. 14 8月, 2014 1 次提交
  2. 23 7月, 2014 1 次提交
  3. 28 4月, 2014 2 次提交
  4. 19 3月, 2014 1 次提交
  5. 15 3月, 2014 1 次提交
  6. 28 11月, 2013 1 次提交
  7. 06 11月, 2013 1 次提交
  8. 04 11月, 2013 4 次提交
  9. 27 8月, 2013 2 次提交
    • A
      perf tools: Add pid to struct thread · 99d725fc
      Adrian Hunter 提交于
      Record pid on struct thread.  The member is named 'pid_' to avoid
      confusion with the 'tid' member which was previously named 'pid'.
      Signed-off-by: NAdrian Hunter <adrian.hunter@intel.com>
      Acked-by: NDavid Ahern <dsahern@gmail.com>
      Cc: David Ahern <dsahern@gmail.com>
      Cc: Frederic Weisbecker <fweisbec@gmail.com>
      Cc: Ingo Molnar <mingo@kernel.org>
      Cc: Jiri Olsa <jolsa@redhat.com>
      Cc: Mike Galbraith <efault@gmx.de>
      Cc: Namhyung Kim <namhyung@gmail.com>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Stephane Eranian <eranian@google.com>
      Link: http://lkml.kernel.org/r/1377522030-27870-3-git-send-email-adrian.hunter@intel.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      99d725fc
    • D
      perf tools: Sample after exit loses thread correlation · 236a3bbd
      David Ahern 提交于
      Occassionally events (e.g., context-switch, sched tracepoints) are losing
      the conversion of sample data associated with a thread. For example:
      
      $ perf record -e sched:sched_switch -c 1 -a -- sleep 5
      $ perf script
      <selected events shown>
          ls 30482 [000] 1379727.583037: sched:sched_switch: prev_comm=ls prev_pid=30482 ...
          ls 30482 [000] 1379727.586339: sched:sched_switch: prev_comm=ls prev_pid=30482 ...
      :30482 30482 [000] 1379727.589462: sched:sched_switch: prev_comm=ls prev_pid=30482 ...
      
      The last line lost the conversion from tid to comm. If you look at the events
      (perf script -D) you see why - a SAMPLE event is generated after the EXIT:
      
      0 1379727589449774 0x1540b0 [0x38]: PERF_RECORD_EXIT(30482:30482):(30482:30482)
      0 1379727589462497 0x1540e8 [0x80]: PERF_RECORD_SAMPLE(IP, 1): 30482/30482: 0xffffffff816416f1 period: 1 addr: 0
      ... thread: :30482:30482
      
      When perf processes the EXIT event the thread is moved to the dead_threads
      list. When the SAMPLE event is processed no thread exists for the pid so a new
      one is created by machine__findnew_thread.
      
      This patch address the problem by delaying the move to the dead_threads list
      until the tid is re-used (per Adrian's suggestion).
      
      With this patch we get the previous example shows:
      
        ls 30482 [000] 1379727.583037: sched:sched_switch: prev_comm=ls prev_pid=30482 ...
        ls 30482 [000] 1379727.586339: sched:sched_switch: prev_comm=ls prev_pid=30482 ...
        ls 30482 [000] 1379727.589462: sched:sched_switch: prev_comm=ls prev_pid=30482 ...
      
      and
      
        0 1379727589449774 0x1540b0 [0x38]: PERF_RECORD_EXIT(30482:30482):(30482:30482)
        0 1379727589462497 0x1540e8 [0x80]: PERF_RECORD_SAMPLE(IP, 1): 30482/30482: 0xffffffff816416f1 period: 1 addr: 0
        ... thread: ls:30482
      
      v4: per Arnaldo's request add dead flag to thread struct and set when task exits
      
      v3: re-do from a time based check to a delayed move to dead_threads list
      
      v2: Rebased to latest perf/core branch. Changed time comparison to use
          a macro which explicitly shows the time basis
      Signed-off-by: NDavid Ahern <dsahern@gmail.com>
      Acked-by: NAdrian Hunter <adrian.hunter@intel.com>
      Cc: Adrian Hunter <adrian.hunter@intel.com>
      Cc: Frederic Weisbecker <fweisbec@gmail.com>
      Cc: Ingo Molnar <mingo@kernel.org>
      Cc: Jiri Olsa <jolsa@redhat.com>
      Cc: Mike Galbraith <efault@gmx.de>
      Cc: Namhyung Kim <namhyung@kernel.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Stephane Eranian <eranian@google.com>
      Link: http://lkml.kernel.org/r/1376491767-84171-1-git-send-email-dsahern@gmail.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      236a3bbd
  10. 12 8月, 2013 2 次提交
  11. 08 8月, 2013 1 次提交
  12. 13 7月, 2013 2 次提交
  13. 28 5月, 2013 1 次提交
  14. 09 12月, 2012 1 次提交
  15. 07 10月, 2012 1 次提交
  16. 21 9月, 2012 1 次提交
    • X
      perf kvm: Events analysis tool · bcf6edcd
      Xiao Guangrong 提交于
      Add 'perf kvm stat' support to analyze kvm vmexit/mmio/ioport smartly
      
      Usage:
      - kvm stat
        run a command and gather performance counter statistics, it is the alias of
        perf stat
      
      - trace kvm events:
        perf kvm stat record, or, if other tracepoints are interesting as well, we
        can append the events like this:
        perf kvm stat record -e timer:* -a
      
        If many guests are running, we can track the specified guest by using -p or
        --pid, -a is used to track events generated by all guests.
      
      - show the result:
        perf kvm stat report
      
      The output example is following:
      13005
      13059
      
      total 2 guests are running on the host
      
      Then, track the guest whose pid is 13059:
      ^C[ perf record: Woken up 1 times to write data ]
      [ perf record: Captured and wrote 0.253 MB perf.data.guest (~11065 samples) ]
      
      See the vmexit events:
      
      Analyze events for all VCPUs:
      
                   VM-EXIT    Samples  Samples%     Time%         Avg time
      
               APIC_ACCESS        460    70.55%     0.01%     22.44us ( +-   1.75% )
                       HLT         93    14.26%    99.98% 832077.26us ( +-  10.42% )
        EXTERNAL_INTERRUPT         64     9.82%     0.00%     35.35us ( +-  14.21% )
         PENDING_INTERRUPT         24     3.68%     0.00%      9.29us ( +-  31.39% )
                 CR_ACCESS          7     1.07%     0.00%      8.12us ( +-   5.76% )
            IO_INSTRUCTION          3     0.46%     0.00%     18.00us ( +-  11.79% )
             EXCEPTION_NMI          1     0.15%     0.00%      5.83us ( +-   -nan% )
      
      Total Samples:652, Total events handled time:77396109.80us.
      
      See the mmio events:
      
      Analyze events for all VCPUs:
      
               MMIO Access    Samples  Samples%     Time%         Avg time
      
              0xfee00380:W        387    84.31%    79.28%      8.29us ( +-   3.32% )
              0xfee00300:W         24     5.23%     9.96%     16.79us ( +-   1.97% )
              0xfee00300:R         24     5.23%     7.83%     13.20us ( +-   3.00% )
              0xfee00310:W         24     5.23%     2.93%      4.94us ( +-   3.84% )
      
      Total Samples:459, Total events handled time:4044.59us.
      
      See the ioport event:
      
      Analyze events for all VCPUs:
      
            IO Port Access    Samples  Samples%     Time%         Avg time
      
               0xc050:POUT          3   100.00%   100.00%     13.75us ( +-  10.83% )
      
      Total Samples:3, Total events handled time:41.26us.
      
      And, --vcpu is used to track the specified vcpu and --key is used to sort the
      result:
      
      Analyze events for VCPU 0:
      
                   VM-EXIT    Samples  Samples%     Time%         Avg time
      
                       HLT         27    13.85%    99.97% 405790.24us ( +-  12.70% )
        EXTERNAL_INTERRUPT         13     6.67%     0.00%     27.94us ( +-  22.26% )
               APIC_ACCESS        146    74.87%     0.03%     21.69us ( +-   2.91% )
            IO_INSTRUCTION          2     1.03%     0.00%     17.77us ( +-  20.56% )
                 CR_ACCESS          2     1.03%     0.00%      8.55us ( +-   6.47% )
         PENDING_INTERRUPT          5     2.56%     0.00%      6.27us ( +-   3.94% )
      
      Total Samples:195, Total events handled time:10959950.90us.
      Signed-off-by: NDong Hao <haodong@linux.vnet.ibm.com>
      Signed-off-by: NRunzhen Wang <runzhen@linux.vnet.ibm.com>
      [ Dong Hao <haodong@linux.vnet.ibm.com>
        Runzhen Wang <runzhen@linux.vnet.ibm.com>:
           - rebase it on current acme's tree
           - fix the compiling-error on i386 ]
      Signed-off-by: NXiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
      Acked-by: NDavid Ahern <dsahern@gmail.com>
      Cc: Avi Kivity <avi@redhat.com>
      Cc: David Ahern <dsahern@gmail.com>
      Cc: Ingo Molnar <mingo@kernel.org>
      Cc: Marcelo Tosatti <mtosatti@redhat.com>
      Cc: kvm@vger.kernel.org
      Cc: Runzhen Wang <runzhen@linux.vnet.ibm.com>
      Link: http://lkml.kernel.org/r/1347870675-31495-4-git-send-email-haodong@linux.vnet.ibm.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      bcf6edcd
  17. 28 11月, 2011 1 次提交
  18. 24 1月, 2011 1 次提交
    • A
      perf threads: Move thread_map to separate file · fd78260b
      Arnaldo Carvalho de Melo 提交于
      To untangle it from struct thread handling, that is tied to symbols, etc.
      
      Right now in the python bindings I'm working on I need just a subset of
      the util/ files, untangling it allows me to do that.
      
      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: <new-submission>
      Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      fd78260b
  19. 04 1月, 2011 1 次提交
    • A
      perf tools: Refactor all_tids to hold nr and the map · 5c98d466
      Arnaldo Carvalho de Melo 提交于
      So that later, we can pass the thread_map instance instead of
      (thread_num, thread_map) for things like perf_evsel__open and friends,
      just like was done with cpu_map.
      
      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: <new-submission>
      Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      5c98d466
  20. 31 7月, 2010 1 次提交
    • A
      perf tools: Release thread resources on PERF_RECORD_EXIT · 591765fd
      Arnaldo Carvalho de Melo 提交于
      For long running sessions with many threads with short lifetimes the
      amount of memory that the buildid process takes is too much.
      
      Since we don't have hist_entries that may be pointing to them, we can
      just release the resources associated with each thread when the exit
      (PERF_RECORD_EXIT) event is received.
      
      For normal processing we need to annotate maps with hits, and thus
      hist_entries pointing to it and drop the ones that had none. Will be
      done in a followup patch.
      
      Cc: David S. Miller <davem@davemloft.net>
      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: <new-submission>
      Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      591765fd
  21. 17 6月, 2010 1 次提交
    • A
      perf session: Remove threads from tree on PERF_RECORD_EXIT · 720a3aeb
      Arnaldo Carvalho de Melo 提交于
      Move them to a session->dead_threads list just like we do with maps that
      are replaced, because we may have hist_entries pointing to them.
      
      This fixes a bug when inserting maps for a new thread that reused the
      TID, mixing maps for two different threads, causing an endless loop.
      
      The code for insering maps should be made more robust but for .35 this
      is the minimalistic patch.
      Reported-by: NIngo Molnar <mingo@elte.hu>
      Cc: David S. Miller <davem@davemloft.net>
      Cc: Frédéric Weisbecker <fweisbec@gmail.com>
      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: <new-submission>
      Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      720a3aeb
  22. 19 4月, 2010 1 次提交
  23. 26 3月, 2010 1 次提交
    • A
      perf symbols: Move map related routines to map.c · 4b8cf846
      Arnaldo Carvalho de Melo 提交于
      Thru series of refactorings functions were being renamed but not
      moved to map.c to reduce patch noise, now lets have them in the
      same place so that use of the symbol system by tools can be
      constrained to building and linking fewer source files:
      symbol.c, map.c and rbtree.c.
      Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      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>
      LKML-Reference: <1269557941-15617-3-git-send-email-acme@infradead.org>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      4b8cf846
  24. 18 3月, 2010 1 次提交
    • Z
      perf events: Change perf parameter --pid to process-wide collection instead of thread-wide · d6d901c2
      Zhang, Yanmin 提交于
      Parameter --pid (or -p) of perf currently means a thread-wide
      collection. For exmaple, if a process whose id is 8888 has 10
      threads, 'perf top -p 8888' just collects the main thread
      statistics. That's misleading. Users are used to attach a whole
      process when debugging a process by gdb. To follow normal usage
      style, the patch change --pid to process-wide collection and add
      --tid (-t) to mean a thread-wide collection.
      
      Usage example is:
      
       # perf top -p 8888
       # perf record -p 8888 -f sleep 10
       # perf stat -p 8888 -f sleep 10
      
      Above commands collect the statistics of all threads of process
      8888.
      Signed-off-by: NZhang Yanmin <yanmin_zhang@linux.intel.com>
      Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      Cc: Avi Kivity <avi@redhat.com>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Sheng Yang <sheng@linux.intel.com>
      Cc: Joerg Roedel <joro@8bytes.org>
      Cc: Jes Sorensen <Jes.Sorensen@redhat.com>
      Cc: Marcelo Tosatti <mtosatti@redhat.com>
      Cc: Gleb Natapov <gleb@redhat.com>
      Cc: zhiteng.huang@intel.com
      Cc: Zachary Amsden <zamsden@redhat.com>
      LKML-Reference: <1268922965-14774-3-git-send-email-acme@infradead.org>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      d6d901c2
  25. 10 3月, 2010 1 次提交
    • A
      perf report: Print the map table just after samples for which no map was found · 65f2ed2b
      Arnaldo Carvalho de Melo 提交于
      If -vv is used just the map table will be printed, -vvv will
      print the symbol table too, with it we can see that we have a
      bug where some samples are not being resolved to a map when we
      get them in the perf.data stream, but after we have it all
      processed, we can find the right map, some reordering probably
      is happening.
      
      Upcoming patches will provide ways to ask for most PERF_SAMPLE_
      conditional samples to be taken for !PERF_RECORD_SAMPLE events
      too, then we'll be able to ask for PERF_SAMPLE_TIME and
      PERF_SAMPLE_CPU to help diagnose this.
      Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      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>
      LKML-Reference: <1268161097-17761-1-git-send-email-acme@infradead.org>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      65f2ed2b
  26. 22 2月, 2010 1 次提交
    • A
      perf tools: Don't use parent comm if not set at fork time · faa5c5c3
      Arnaldo Carvalho de Melo 提交于
      As the parent comm then is worthless, confusing users about the
      thread where the sample really happened, leading to think that
      the sample happened in the parent, not where it really happened,
      in the children of a thread for which a PERF_RECORD_COMM event
      was not received.
      Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      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>
      LKML-Reference: <1266627727-19715-1-git-send-email-acme@infradead.org>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      faa5c5c3
  27. 04 2月, 2010 1 次提交
    • A
      perf symbols: Remove perf_session usage in symbols layer · 9de89fe7
      Arnaldo Carvalho de Melo 提交于
      I noticed while writing the first test in 'perf regtest' that to
      just test the symbol handling routines one needs to create a
      perf session, that is a layer centered on a perf.data file,
      events, etc, so I untied these layers.
      
      This reduces the complexity for the users as the number of
      parameters to most of the symbols and session APIs now was
      reduced while not adding more state to all the map instances by
      only having data that is needed to split the kernel (kallsyms
      and ELF symtab sections) maps and do vmlinux relocation on the
      main kernel map.
      Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      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>
      LKML-Reference: <1265223128-11786-1-git-send-email-acme@infradead.org>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      9de89fe7
  28. 16 1月, 2010 1 次提交
  29. 14 1月, 2010 1 次提交
    • A
      perf tools: Encode kernel module mappings in perf.data · b7cece76
      Arnaldo Carvalho de Melo 提交于
      We were always looking at the running machine /proc/modules,
      even when processing a perf.data file, which only makes sense
      when we're doing 'perf record' and 'perf report' on the same
      machine, and in close sucession, or if we don't use modules at
      all, right Peter? ;-)
      
      Now, at 'perf record' time we read /proc/modules, find the long
      path for modules, and put them as PERF_MMAP events, just like we
      did to encode the reloc reference symbol for vmlinux. Talking
      about that now it is encoded in .pgoff, so that we can use
      .{start,len} to store the address boundaries for the kernel so
      that when we reconstruct the kmaps tree we can do lookups right
      away, without having to fixup the end of the kernel maps like we
      did in the past (and now only in perf record).
      
      One more step in the 'perf archive' direction when we'll finally
      be able to collect data in one machine and analyse in another.
      Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      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>
      LKML-Reference: <1263396139-4798-1-git-send-email-acme@infradead.org>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      b7cece76
  30. 14 12月, 2009 3 次提交
    • A
      perf session: Move kmaps to perf_session · 4aa65636
      Arnaldo Carvalho de Melo 提交于
      There is still some more work to do to disentangle map creation
      from DSO loading, but this happens only for the kernel, and for
      the early adopters of perf diff, where this disentanglement
      matters most, we'll be testing different kernels, so no problem
      here.
      
      Further clarification: right now we create the kernel maps for
      the various modules and discontiguous kernel text maps when
      loading the DSO, we should do it as a two step process, first
      creating the maps, for multiple mappings with the same DSO
      store, then doing the dso load just once, for the first hit on
      one of the maps sharing this DSO backing store.
      Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      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>
      LKML-Reference: <1260741029-4430-6-git-send-email-acme@infradead.org>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      4aa65636
    • A
      perf session: Move the global threads list to perf_session · b3165f41
      Arnaldo Carvalho de Melo 提交于
      So that we can process two perf.data files.
      
      We still need to add a O_MMAP mode for perf_session so that we
      can do all the mmap stuff in it.
      Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      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>
      LKML-Reference: <1260741029-4430-5-git-send-email-acme@infradead.org>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      b3165f41
    • A
      perf session: Register the idle thread in perf_session__process_events · 13df45ca
      Arnaldo Carvalho de Melo 提交于
      No need for all tools to register it and then immediately call
      perf_session__process_events.
      Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      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>
      LKML-Reference: <1260741029-4430-3-git-send-email-acme@infradead.org>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      13df45ca
  31. 12 12月, 2009 1 次提交
    • A
      perf symbols: Allow lookups by symbol name too · 79406cd7
      Arnaldo Carvalho de Melo 提交于
      Configurable via symbol_conf.sort_by_name, so that the cost of an
      extra rb_node on all 'struct symbol' instances is not paid by tools
      that only want to decode addresses.
      
      How to use it:
      
      	symbol_conf.sort_by_name = true;
      	symbol_init(&symbol_conf);
      
      	struct map *map = map_groups__find_by_name(kmaps, MAP__VARIABLE, "[kernel.kallsyms]");
      
      	if (map == NULL) {
      		pr_err("couldn't find map!\n");
      		kernel_maps__fprintf(stdout);
      	} else {
      		struct symbol *sym = map__find_symbol_by_name(map, sym_filter, NULL);
      		if (sym == NULL)
      			pr_err("couldn't find symbol %s!\n", sym_filter);
      		else
      			pr_info("symbol %s: %#Lx-%#Lx \n", sym_filter, sym->start, sym->end);
      	}
      
      Looking over the vmlinux/kallsyms is common enough that I'll add a
      variable to the upcoming struct perf_session to avoid the need to
      use map_groups__find_by_name to get the main vmlinux/kallsyms map.
      
      The above example looks on the 'variable' symtab, but it is just
      like that for the functions one.
      
      Also the sort operation is done when we first use
      map__find_symbol_by_name, in a lazy way.
      Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      Cc: Frédéric Weisbecker <fweisbec@gmail.com>
      Cc: Masami Hiramatsu <mhiramat@redhat.com>
      Cc: Mike Galbraith <efault@gmx.de>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Paul Mackerras <paulus@samba.org>
      LKML-Reference: <1260564622-12392-1-git-send-email-acme@infradead.org>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      79406cd7