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  1. 02 7月, 2009 5 次提交
  3. 01 7月, 2009 8 次提交
    • I
      perf_counter tools: Add more warnings and fix/annotate them · f37a291c
      由 Ingo Molnar 提交于 
      Enable -Wextra. This found a few real bugs plus a number
of signed/unsigned type mismatches/uncleanlinesses. It
also required a few annotations

All things considered it was still worth it so lets try with
this enabled for now.

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      f37a291c
    • I
      perf report: Fix HV bit mismerge · 88a69dfb
      由 Ingo Molnar 提交于 
      Fix:

 builtin-report.c: In function ‘hist_entry__add’:
 builtin-report.c:1015: error: case label not within a switch statement
 builtin-report.c:1017: error: break statement not within loop or switch

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      88a69dfb
    • F
      perf_counter tools: Resolve symbols in callchains · 4424961a
      由 Frederic Weisbecker 提交于 
      This patch resolves the names, when possible, of each ip
present in the callchains while using the -c option with perf
report.

Example:

5.40%  [k] __d_lookup
             5.37%
                perf_callchain
                perf_counter_overflow
                intel_pmu_handle_irq
                perf_counter_nmi_handler
                notifier_call_chain
                atomic_notifier_call_chain
                notify_die
                do_nmi
                nmi
                do_lookup
                __link_path_walk
                path_walk
                do_path_lookup
                user_path_at
                sys_faccessat
                sys_access
                system_call_fastpath
                0x7fb609846f77

             0.01%
                perf_callchain
                perf_counter_overflow
                intel_pmu_handle_irq
                perf_counter_nmi_handler
                notifier_call_chain
                atomic_notifier_call_chain
                notify_die
                do_nmi
                nmi
                do_lookup
                __link_path_walk
                path_walk
                do_path_lookup
                user_path_at
                sys_faccessat
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Anton Blanchard <anton@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <1246419315-9968-3-git-send-email-fweisbec@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      4424961a
    • A
      perf report: Add hypervisor dso · fb9c8188
      由 Anton Blanchard 提交于 
      Add a dso for hypervisor samples. We don't get any symbol
information on the ppc64 hypervisor but this at least gives
us a high level summary of the time spent in there.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Cc: a.p.zijlstra@chello.nl
Cc: paulus@samba.org
LKML-Reference: <20090630230141.182536873@samba.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      fb9c8188
    • A
      perf report: Fix reporting of hypervisor · d8db1b57
      由 Anton Blanchard 提交于 
      PERF_EVENT_MISC_* is not a bitmask, so we have to mask and compare.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Cc: a.p.zijlstra@chello.nl
Cc: paulus@samba.org
LKML-Reference: <20090630230141.088394681@samba.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      d8db1b57
    • A
      perf report: Add --symbols parameter · 7bec7a91
      由 Arnaldo Carvalho de Melo 提交于 
      So that we can filter by symbol name.

The 'pfunct' utility in the 'dwarves' package can be used to
create a file with the functions one wants.

Example:

[acme@doppio pahole]$ pfunct /usr/lib/debug/usr/lib64/libdw-0.141.so.debug | grep dwarf > /tmp/dwarf.symbols
[acme@doppio pahole]$ wc -l /tmp/dwarf.symbols
93 /tmp/dwarf.symbols
[acme@doppio pahole]$ head -3 /tmp/dwarf.symbols
dwfl_addrdwarf
dwfl_module_getdwarf
dwfl_getdwarf
[acme@doppio pahole]$ perf report --sort comm,dso,symbol --comms pahole --dsos /usr/lib64/libdw-0.141.so --symbols file:///tmp/dwarf.symbols

    33.99%            pahole  /usr/lib64/libdw-0.141.so  [.] dwarf_tag
    29.07%            pahole  /usr/lib64/libdw-0.141.so  [.] dwarf_decl_file
    27.71%            pahole  /usr/lib64/libdw-0.141.so  [.] dwarf_getsrclines
     4.54%            pahole  /usr/lib64/libdw-0.141.so  0x00000000007400
     3.93%            pahole  /usr/lib64/libdw-0.141.so  [.] dwarf_decl_line
     0.46%            pahole  /usr/lib64/libdw-0.141.so  [.] dwarf_getlocation
     0.18%            pahole  /usr/lib64/libdw-0.141.so  [.] __libdwarf_next_prime
     0.13%            pahole  /usr/lib64/libdw-0.141.so  [.] dwarf_diecu

[acme@doppio pahole]$
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1246399282-20934-4-git-send-email-acme@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      7bec7a91
    • A
      perf report: Add --comms parameter · cc8b88b1
      由 Arnaldo Carvalho de Melo 提交于 
      So that we can filter by comm. Symbols in other comms won't be
accounted for.
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1246399282-20934-3-git-send-email-acme@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      cc8b88b1
    • A
      perf report: Add --dsos parameter · 25903407
      由 Arnaldo Carvalho de Melo 提交于 
      So that we can filter by dso. Symbols in other dsos won't be
accounted for.
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1246399282-20934-2-git-send-email-acme@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      25903407
  5. 26 6月, 2009 5 次提交
  7. 23 6月, 2009 1 次提交
  9. 22 6月, 2009 1 次提交
  11. 20 6月, 2009 2 次提交
    • F
      perfcounter: Handle some IO return values · eadc84cc
      由 Frederic Weisbecker 提交于 
      Building perfcounter tools raises the following warnings:

 builtin-record.c: In function ‘atexit_header’:
 builtin-record.c:464: erreur: ignoring return value of ‘pwrite’, declared with attribute warn_unused_result
 builtin-record.c: In function ‘__cmd_record’:
 builtin-record.c:503: erreur: ignoring return value of ‘read’, declared with attribute warn_unused_result

 builtin-report.c: In function ‘__cmd_report’:
 builtin-report.c:1403: erreur: ignoring return value of ‘read’, declared with attribute warn_unused_result

This patch handles these IO return values.
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1245456100-5477-1-git-send-email-fweisbec@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      eadc84cc
    • P
      perf_counter tools: Define and use our own u64, s64 etc. definitions · 9cffa8d5
      由 Paul Mackerras 提交于 
      On 64-bit powerpc, __u64 is defined to be unsigned long rather than
unsigned long long.  This causes compiler warnings every time we
print a __u64 value with %Lx.

Rather than changing __u64, we define our own u64 to be unsigned long
long on all architectures, and similarly s64 as signed long long.
For consistency we also define u32, s32, u16, s16, u8 and s8.  These
definitions are put in a new header, types.h, because these definitions
are needed in util/string.h and util/symbol.h.

The main change here is the mechanical change of __[us]{64,32,16,8}
to remove the "__".  The other changes are:

* Create types.h
* Include types.h in perf.h, util/string.h and util/symbol.h
* Add types.h to the LIB_H definition in Makefile
* Added (u64) casts in process_overflow_event() and print_sym_table()
  to kill two remaining warnings.
Signed-off-by: NPaul Mackerras <paulus@samba.org>
Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: benh@kernel.crashing.org
LKML-Reference: <19003.33494.495844.956580@cargo.ozlabs.ibm.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      9cffa8d5
  13. 19 6月, 2009 2 次提交
  15. 18 6月, 2009 7 次提交
    • I
      perf report: Filter to parent set by default · b8e6d829
      由 Ingo Molnar 提交于 
      Make it easier to use parent filtering - default to a filtered
output. Also add the parent column so that we get collapsing but
dont display it by default.

add --no-exclude-other to override this.

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      b8e6d829
    • P
      perf_counter tools: Handle lost events · 9d91a6f7
      由 Peter Zijlstra 提交于 
      Make use of the new ->data_tail mechanism to tell kernel-space
about user-space draining the data stream. Emit lost events
(and display them) if they happen.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      9d91a6f7
    • P
      perf_counter tools: Add and use isprint() · a73c7d84
      由 Peter Zijlstra 提交于 
      Introduce isprint() to print out raw event dumps to ASCII, etc.

(This is an extension to upstream Git's ctype.c.)
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <new-submission>
[ removed openssl.h inclusion from util.h - it leaked ctype.h ]
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      a73c7d84
    • I
      perf report: Add validation of call-chain entries · 7522060c
      由 Ingo Molnar 提交于 
      Add boundary checks for call-chain events. In case of corrupted
entries we could crash otherwise.

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      7522060c
    • I
      perf report: Tidy up the "--parent <regex>" and "--sort parent" call-chain features · b25bcf2f
      由 Ingo Molnar 提交于 
      Instead of the ambigious 'call' naming use the much more
specific 'parent' naming:

 - rename --call <regex> to --parent <regex>

 - rename --sort call to --sort parent

 - rename [unmatched] to [other] - to signal that this is not
   an error but the inverse set

Also add pagefaults to the default parent-symbol pattern too,
as it's a 'syscall overhead category' in a sense.

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      b25bcf2f
    • P
      perf_counter tools: Replace isprint() with issane() · 5aa75a0f
      由 Peter Zijlstra 提交于 
      The Git utils came with a ctype replacement that doesn't provide
isprint(). Add a replacement.

Solves a build bug on certain distros.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      5aa75a0f
    • P
      perf report: Add --sort <call> --call <$regex> · 6e7d6fdc
      由 Peter Zijlstra 提交于 
      Implement sorting by callchain symbols, --sort <call>.

It will create a new column which will show a match to
--call $regex or "[unmatched]".
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      6e7d6fdc
  17. 15 6月, 2009 3 次提交
    • I
      perf report: Fix 32-bit printf format · e2eae0f5
      由 Ingo Molnar 提交于 
      Yong Wang reported the following compiler warning:

 builtin-report.c: In function 'process_overflow_event':
 builtin-report.c:984: error: cast to pointer from integer of different size

Which happens because we try to print ->ips[] out with a limited
format, losing the high 32 bits. Print it out using %016Lx instead.
Reported-by: NYong Wang <yong.y.wang@linux.intel.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      e2eae0f5
    • I
      perf report: Add per system call overhead histogram · 3dfabc74
      由 Ingo Molnar 提交于 
      Take advantage of call-graph percounter sampling/recording to
display a non-trivial histogram: the true, collapsed/summarized
cost measurement, on a per system call total overhead basis:

 aldebaran:~/linux/linux/tools/perf> ./perf record -g -a -f ~/hackbench 10
 aldebaran:~/linux/linux/tools/perf> ./perf report -s symbol --syscalls | head -10
 #
 # (3536 samples)
 #
 # Overhead  Symbol
 # ........  ......
 #
     40.75%  [k] sys_write
     40.21%  [k] sys_read
      4.44%  [k] do_nmi
 ...

This is done by accounting each (reliable) call-chain that chains back
to a given system call to that system call function.

[ So in the above example we can see that hackbench spends about 40% of
  its total time somewhere in sys_write() and 40% somewhere in
  sys_read(), the rest of the time is spent in user-space. The time
  is not spent in sys_write() _itself_ but in one of its many child
  functions. ]

Or, a recording of a (source files are already in the page-cache) kernel build:

 $ perf record -g -m 512 -f -- make -j32 kernel
 $ perf report -s s --syscalls | grep '\[k\]' | grep -v nmi

     4.14%  [k] do_page_fault
     1.20%  [k] sys_write
     1.10%  [k] sys_open
     0.63%  [k] sys_exit_group
     0.48%  [k] smp_apic_timer_interrupt
     0.37%  [k] sys_read
     0.37%  [k] sys_execve
     0.20%  [k] sys_mmap
     0.18%  [k] sys_close
     0.14%  [k] sys_munmap
     0.13%  [k] sys_poll
     0.09%  [k] sys_newstat
     0.07%  [k] sys_clone
     0.06%  [k] sys_newfstat
     0.05%  [k] sys_access
     0.05%  [k] schedule

Shows the true total cost of each syscall variant that gets used
during a kernel build. This profile reveals it that pagefaults are
the costliest, followed by read()/write().

An interesting detail: timer interrupts cost 0.5% - or 0.5 seconds
per 100 seconds of kernel build-time. (this was done with HZ=1000)

The summary is done in 'perf report', i.e. in the post-processing
stage - so once we have a good call-graph recording, this type of
non-trivial high-level analysis becomes possible.

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      3dfabc74
    • I
      perf record/report: Add call graph / call chain profiling · 3efa1cc9
      由 Ingo Molnar 提交于 
      Add the first steps of call-graph profiling:

 - add the -c (--call-graph) option to perf record
 - parse the call-graph record and printout out under -D (--dump-trace)

The call-graph data is not put into the histogram yet, but it
can be seen that it's being processed correctly:

0x3ce0 [0x38]: event: 35
.
. ... raw event: size 56 bytes
.  0000:  23 00 00 00 05 00 38 00 d4 df 0e 81 ff ff ff ff  #.....8........
.  0010:  60 0b 00 00 60 0b 00 00 03 00 00 00 01 00 02 00  `...`..........
.  0020:  d4 df 0e 81 ff ff ff ff a0 61 ed 41 36 00 00 00  .........a.A6..
.  0030:  04 92 e6 41 36 00 00 00                          .a.A6..
.
0x3ce0 [0x38]: PERF_EVENT (IP, 5): 2912: 0xffffffff810edfd4 period: 1
... chain: u:2, k:1, nr:3
.....  0: 0xffffffff810edfd4
.....  1: 0x3641ed61a0
.....  2: 0x3641e69204
 ... thread: perf:2912
 ...... dso: [kernel]

This shows a 3-entry call-graph: with 1 kernel-space and two user-space
entries

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      3efa1cc9
  19. 14 6月, 2009 1 次提交
    • I
      perf report: Print out raw events in hexa · 8465b050
      由 Ingo Molnar 提交于 
      Print out events in hexa dump format, when -D is specified:

0x4868 [0x48]: event: 1
.
. ... raw event: size 72 bytes
.  0000:  01 00 00 00 00 00 48 00 d4 72 00 00 d4 72 00 00  ......H..r...r.
.  0010:  00 00 40 f2 3e 00 00 00 00 30 01 00 00 00 00 00  ..@.>....0.....
.  0020:  00 00 00 00 00 00 00 00 2f 75 73 72 2f 6c 69 62  ......../usr/li
.  0030:  36 34 2f 6c 69 62 65 6c 66 2d 30 2e 31 34 31 2e  64/libelf-0.141
.  0040:  73 6f 00 00 00 00 00 00                          f-0.141
.
0x4868 [0x48]: PERF_EVENT_MMAP 29396: [0x3ef2400000(0x13000) @ (nil)]: /usr/lib64/libelf-0.141.so

This helps the debugging of mis-parsing of data files, and helps
the addition of new sample/trace formats.

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      8465b050
  21. 11 6月, 2009 2 次提交
    • I
      perf_counter tools: Clean up u64 usage · 729ff5e2
      由 Ingo Molnar 提交于 
      A build error slipped in:

 builtin-report.c: In function ‘hist_entry__fprintf’:
 builtin-report.c:711: error: format ‘%12d’ expects type ‘int’, but argument 3 has type ‘uint64_t’

Because we got a bit sloppy with those types. uint64_t really sucks,
because there's no printf format for it. So standardize on __u64
instead - for all types that go to or come from the ABI (which is __u64),
or for values that need to be large enough even on 32-bit.

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      729ff5e2
    • P
      perf_counter tools: Normalize data using per sample period data · ea1900e5
      由 Peter Zijlstra 提交于 
      When we use variable period sampling, add the period to the sample
data and use that to normalize the samples.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      ea1900e5
  23. 10 6月, 2009 1 次提交
  25. 09 6月, 2009 2 次提交
    • I
      perf_counter tools: Standardize color printing · aefcf37b
      由 Ingo Molnar 提交于 
      The rule is:

 - high overhead: red
 -  mid overhead: green
 -  low overhead: normal (white/black)

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      aefcf37b
    • P
      perf report: Add support for profiling JIT generated code · 80d496be
      由 Pekka Enberg 提交于 
      This patch adds support for profiling JIT generated code to 'perf
report'. A JIT compiler is required to generate a "/tmp/perf-$PID.map"
symbols map that is parsed when looking and displaying symbols.

Thanks to Peter Zijlstra for his help with this patch!

Example "perf report" output with the Jato JIT:

 #
 # (40311 samples)
 #
 # Overhead           Command  Shared Object              Symbol
 # ........  ................  .........................  ......
 #
     97.80%              jato  /tmp/perf-11915.map        [.] Fibonacci.fib(I)I
      0.56%              jato  00000000b7fa023b           0x000000b7fa023b
      0.45%              jato  /tmp/perf-11915.map        [.] Fibonacci.main([Ljava/lang/String;)V
      0.38%              jato  [kernel]                   [k] get_page_from_freelist
      0.06%              jato  [kernel]                   [k] kunmap_atomic
      0.05%              jato  ./jato                     [.] utf8Hash
      0.04%              jato  ./jato                     [.] executeJava
      0.04%              jato  ./jato                     [.] defineClass

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: NPekka Enberg <penberg@cs.helsinki.fi>
Cc: a.p.zijlstra@chello.nl
Cc: acme@redhat.com
LKML-Reference: <Pine.LNX.4.64.0906082111590.12407@melkki.cs.Helsinki.FI>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      80d496be