linux.git/tools/perf/util, branch v4.8-rc2

perf probe ppc64le: Fix probe location when using DWARF

2016-08-09T15:14:29+00:00

Powerpc has Global Entry Point and Local Entry Point for functions.  LEP
catches call from both the GEP and the LEP. Symbol table of ELF contains
GEP and Offset from which we can calculate LEP, but debuginfo does not
have LEP info.

Currently, perf prioritize symbol table over dwarf to probe on LEP for
ppc64le. But when user tries to probe with function parameter, we fall
back to using dwarf(i.e. GEP) and when function called via LEP, probe
will never hit.

For example:

  $ objdump -d vmlinux
    ...
    do_sys_open():
    c0000000002eb4a0:       e8 00 4c 3c     addis   r2,r12,232
    c0000000002eb4a4:       60 00 42 38     addi    r2,r2,96
    c0000000002eb4a8:       a6 02 08 7c     mflr    r0
    c0000000002eb4ac:       d0 ff 41 fb     std     r26,-48(r1)

  $ sudo ./perf probe do_sys_open
  $ sudo cat /sys/kernel/debug/tracing/kprobe_events
    p:probe/do_sys_open _text+3060904

  $ sudo ./perf probe 'do_sys_open filename:string'
  $ sudo cat /sys/kernel/debug/tracing/kprobe_events
    p:probe/do_sys_open _text+3060896 filename_string=+0(%gpr4):string

For second case, perf probed on GEP. So when function will be called via
LEP, probe won't hit.

  $ sudo ./perf record -a -e probe:do_sys_open ls
    [ perf record: Woken up 1 times to write data ]
    [ perf record: Captured and wrote 0.195 MB perf.data ]

To resolve this issue, let's not prioritize symbol table, let perf
decide what it wants to use. Perf is already converting GEP to LEP when
it uses symbol table. When perf uses debuginfo, let it find LEP offset
form symbol table. This way we fall back to probe on LEP for all cases.

After patch:

  $ sudo ./perf probe 'do_sys_open filename:string'
  $ sudo cat /sys/kernel/debug/tracing/kprobe_events
    p:probe/do_sys_open _text+3060904 filename_string=+0(%gpr4):string

  $ sudo ./perf record -a -e probe:do_sys_open ls
    [ perf record: Woken up 1 times to write data ]
    [ perf record: Captured and wrote 0.197 MB perf.data (11 samples) ]

Signed-off-by: Ravi Bangoria 
Acked-by: Masami Hiramatsu 
Cc: Alexander Shishkin 
Cc: Ananth N Mavinakayanahalli 
Cc: Balbir Singh 
Cc: Namhyung Kim 
Cc: Naveen N. Rao 
Cc: Peter Zijlstra 
Cc: Wang Nan 
Link: http://lkml.kernel.org/r/1470723805-5081-2-git-send-email-ravi.bangoria@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo

perf probe: Add function to post process kernel trace events

2016-08-09T15:09:59+00:00

Instead of inline code, introduce function to post process kernel
probe trace events.

Signed-off-by: Ravi Bangoria 
Acked-by: Masami Hiramatsu 
Cc: Alexander Shishkin 
Cc: Ananth N Mavinakayanahalli 
Cc: Balbir Singh 
Cc: Namhyung Kim 
Cc: Naveen N. Rao 
Cc: Peter Zijlstra 
Cc: Wang Nan 
Link: http://lkml.kernel.org/r/1470723805-5081-1-git-send-email-ravi.bangoria@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo

perf probe: Support signedness casting

2016-08-09T13:52:22+00:00

The 'perf probe' tool detects a variable's type and use the detected
type to add a new probe. Then, kprobes prints its variable in
hexadecimal format if the variable is unsigned and prints in decimal if
it is signed.

We sometimes want to see unsigned variable in decimal format (i.e.
sector_t or size_t). In that case, we need to investigate the variable's
size manually to specify just signedness.

This patch add signedness casting support. By specifying "s" or "u" as a
type, perf-probe will investigate variable size as usual and use the
specified signedness.

E.g. without this:

  $ perf probe -a 'submit_bio bio->bi_iter.bi_sector'
  Added new event:
    probe:submit_bio     (on submit_bio with bi_sector=bio->bi_iter.bi_sector)
  You can now use it in all perf tools, such as:
          perf record -e probe:submit_bio -aR sleep 1
  $ cat trace_pipe|head
          dbench-9692  [003] d..1   971.096633: submit_bio: (submit_bio+0x0/0x140) bi_sector=0x3a3d00
          dbench-9692  [003] d..1   971.096685: submit_bio: (submit_bio+0x0/0x140) bi_sector=0x1a3d80
          dbench-9692  [003] d..1   971.096687: submit_bio: (submit_bio+0x0/0x140) bi_sector=0x3a3d80
...
  // need to investigate the variable size
  $ perf probe -a 'submit_bio bio->bi_iter.bi_sector:s64'
  Added new event:
    probe:submit_bio     (on submit_bio with bi_sector=bio->bi_iter.bi_sector:s64)
  You can now use it in all perf tools, such as:
        perf record -e probe:submit_bio -aR sleep 1

  With this:

  // just use "s" to cast its signedness
  $ perf probe -v -a 'submit_bio bio->bi_iter.bi_sector:s'
  Added new event:
    probe:submit_bio     (on submit_bio with bi_sector=bio->bi_iter.bi_sector:s)
  You can now use it in all perf tools, such as:
          perf record -e probe:submit_bio -aR sleep 1
  $ cat trace_pipe|head
          dbench-9689  [001] d..1  1212.391237: submit_bio: (submit_bio+0x0/0x140) bi_sector=128
          dbench-9689  [001] d..1  1212.391252: submit_bio: (submit_bio+0x0/0x140) bi_sector=131072
          dbench-9697  [006] d..1  1212.398611: submit_bio: (submit_bio+0x0/0x140) bi_sector=30208

  This commit also update perf-probe.txt to describe "types". Most parts
  are based on existing documentation: Documentation/trace/kprobetrace.txt

Committer note:

Testing using 'perf trace':

  # perf probe -a 'submit_bio bio->bi_iter.bi_sector'
  Added new event:
    probe:submit_bio     (on submit_bio with bi_sector=bio->bi_iter.bi_sector)

  You can now use it in all perf tools, such as:

	perf record -e probe:submit_bio -aR sleep 1

  # trace --no-syscalls --ev probe:submit_bio
      0.000 probe:submit_bio:(ffffffffac3aee00) bi_sector=0xc133c0)
   3181.861 probe:submit_bio:(ffffffffac3aee00) bi_sector=0x6cffb8)
   3181.881 probe:submit_bio:(ffffffffac3aee00) bi_sector=0x6cffc0)
   3184.488 probe:submit_bio:(ffffffffac3aee00) bi_sector=0x6cffc8)

   4717.927 probe:submit_bio:(ffffffffac3aee00) bi_sector=0x4dc7a88)
   4717.970 probe:submit_bio:(ffffffffac3aee00) bi_sector=0x4dc7880)
  ^C[root@jouet ~]#

Now, using this new feature:

[root@jouet ~]# perf probe -a 'submit_bio bio->bi_iter.bi_sector:s'
Added new event:
  probe:submit_bio     (on submit_bio with bi_sector=bio->bi_iter.bi_sector:s)

You can now use it in all perf tools, such as:

	perf record -e probe:submit_bio -aR sleep 1

  [root@jouet ~]# trace --no-syscalls --ev probe:submit_bio
     0.000 probe:submit_bio:(ffffffffac3aee00) bi_sector=7145704)
     0.017 probe:submit_bio:(ffffffffac3aee00) bi_sector=7145712)
     0.019 probe:submit_bio:(ffffffffac3aee00) bi_sector=7145720)
     2.567 probe:submit_bio:(ffffffffac3aee00) bi_sector=7145728)
  5631.919 probe:submit_bio:(ffffffffac3aee00) bi_sector=0)
  5631.941 probe:submit_bio:(ffffffffac3aee00) bi_sector=8)
  5631.945 probe:submit_bio:(ffffffffac3aee00) bi_sector=16)
  5631.948 probe:submit_bio:(ffffffffac3aee00) bi_sector=24)
  ^C#

With callchains:

  # trace --no-syscalls --ev probe:submit_bio/max-stack=10/
     0.000 probe:submit_bio:(ffffffffac3aee00) bi_sector=50662544)
                                       submit_bio+0xa8200001 ([kernel.kallsyms])
                                       submit_bh+0xa8200013 ([kernel.kallsyms])
                                       jbd2_journal_commit_transaction+0xa8200691 ([kernel.kallsyms])
                                       kjournald2+0xa82000ca ([kernel.kallsyms])
                                       kthread+0xa82000d8 ([kernel.kallsyms])
                                       ret_from_fork+0xa820001f ([kernel.kallsyms])
     0.023 probe:submit_bio:(ffffffffac3aee00) bi_sector=50662552)
                                       submit_bio+0xa8200001 ([kernel.kallsyms])
                                       submit_bh+0xa8200013 ([kernel.kallsyms])
                                       jbd2_journal_commit_transaction+0xa8200691 ([kernel.kallsyms])
                                       kjournald2+0xa82000ca ([kernel.kallsyms])
                                       kthread+0xa82000d8 ([kernel.kallsyms])
                                       ret_from_fork+0xa820001f ([kernel.kallsyms])
     0.027 probe:submit_bio:(ffffffffac3aee00) bi_sector=50662560)
                                       submit_bio+0xa8200001 ([kernel.kallsyms])
                                       submit_bh+0xa8200013 ([kernel.kallsyms])
                                       jbd2_journal_commit_transaction+0xa8200691 ([kernel.kallsyms])
                                       kjournald2+0xa82000ca ([kernel.kallsyms])
                                       kthread+0xa82000d8 ([kernel.kallsyms])
                                       ret_from_fork+0xa820001f ([kernel.kallsyms])
     2.593 probe:submit_bio:(ffffffffac3aee00) bi_sector=50662568)
                                       submit_bio+0xa8200001 ([kernel.kallsyms])
                                       submit_bh+0xa8200013 ([kernel.kallsyms])
                                       journal_submit_commit_record+0xa82001ac ([kernel.kallsyms])
                                       jbd2_journal_commit_transaction+0xa82012e8 ([kernel.kallsyms])
                                       kjournald2+0xa82000ca ([kernel.kallsyms])
                                       kthread+0xa82000d8 ([kernel.kallsyms])
                                       ret_from_fork+0xa820001f ([kernel.kallsyms])
  ^C#

Signed-off-by: Naohiro Aota 
Tested-by: Arnaldo Carvalho de Melo 
Cc: Alexander Shishkin 
Cc: Hemant Kumar 
Cc: Masami Hiramatsu 
Cc: Peter Zijlstra 
Cc: Wang Nan 
Link: http://lkml.kernel.org/r/1470710408-23515-1-git-send-email-naohiro.aota@hgst.com
Signed-off-by: Arnaldo Carvalho de Melo

perf probe: Fix module name matching

2016-08-09T13:48:09+00:00

If module is "module" then dso->short_name is "[module]".  Substring
comparing is't enough: "raid10" matches to "[raid1]".  This patch also
checks terminating zero in module name.

Signed-off-by: Konstantin Khlebnikov 
Acked-by: Masami Hiramatsu 
Link: http://lkml.kernel.org/r/147039975648.715620.12985971832789032159.stgit@buzz
Signed-off-by: Arnaldo Carvalho de Melo

perf probe: Adjust map->reloc offset when finding kernel symbol from map

2016-08-09T13:47:43+00:00

Adjust map->reloc offset for the unmapped address when finding
alternative symbol address from map, because KASLR can relocate the
kernel symbol address.

The same adjustment has been done when finding appropriate kernel symbol
address from map which was introduced by commit f90acac75713 ("perf
probe: Find given address from offline dwarf")

Reported-by: Arnaldo Carvalho de Melo 
Signed-off-by: Masami Hiramatsu 
Cc: Alexei Starovoitov 
Cc: Wang Nan 
Link: http://lkml.kernel.org/r/20160806192948.e366f3fbc4b194de600f8326@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf hists: Trim libtraceevent trace_seq buffers

2016-08-09T13:46:56+00:00

When we use libtraceevent to format trace event fields into printable
strings to use in hist entries it is important to trim it from the
default 4 KiB it starts with to what is really used, to reduce the
memory footprint, so use realloc(seq.buffer, seq.len + 1) when returning
the seq.buffer formatted with the fields contents.

Reported-and-Tested-by: Wang Nan 
Cc: Adrian Hunter 
Cc: David Ahern 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Link: http://lkml.kernel.org/n/tip-t3hl7uxmilrkigzmc90rlhk2@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

Merge tag 'perf-core-for-mingo-20160803' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/urgent

2016-08-04T09:02:38+00:00

Pull perf/core improvements and fixes from Arnaldo Carvalho de Melo:

New features:

- Add --sample-cpu to 'perf record', to explicitely ask for sampling
  the CPU (Jiri Olsa)

Fixes:

- Fix processing of multi byte chunks in objdump output, fixing
  disassemble processing for annotation on at least ARM64 (Jan Stancek)

- Use SyS_epoll_wait in a BPF 'perf test' entry instead of sys_epoll_wait, that
  is not present in the DWARF info in vmlinux files (Arnaldo Carvalho de Melo)

- Add -wno-shadow when processing files using perl headers, fixing
  the build on Fedora Rawhide and Arch Linux (Namhyung Kim)

Infrastructure changes:

- Annotate prep work to better catch and report errors related to
  using objdump to disassemble DSOs (Arnaldo Carvalho de Melo)

- Add 'alloc', 'scnprintf' and 'and' methods for bitmap processing (Jiri Olsa)

- Add nested output resorting callback in hists processing (Jiri Olsa)

Signed-off-by: Arnaldo Carvalho de Melo 
Signed-off-by: Ingo Molnar

perf record: Add --sample-cpu option

2016-08-02T19:33:29+00:00

Adding --sample-cpu option to be able to explicitly enable CPU sample
type. Currently it's only enable implicitly in case the target is cpu
related.

It will be useful for following c2c record tool.

Signed-off-by: Jiri Olsa 
Cc: David Ahern 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1470074555-24889-8-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf hists: Introduce output_resort_cb method

2016-08-02T19:33:28+00:00

When dealing with nested hist entries it's helpful to have a way to
resort those nested objects.

Adding optional callback call into output_resort function and following
new interface function:

  typedef int (*hists__resort_cb_t)(struct hist_entry *he);

  void hists__output_resort_cb(struct hists *hists,
                               struct ui_progress *prog,
                               hists__resort_cb_t cb);

Signed-off-by: Jiri Olsa 
Cc: David Ahern 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1470074555-24889-7-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf annotate: Plug filename string leak

2016-08-01T21:49:13+00:00

If dso__build_id_filename(..., NULL, ...) returns !NULL its because it
allocated it, so, when reaching the  'if (dso__is_kcore()) test, we
already checked that and were just "fallbacking" to using
dso->long_name, but without freeing filename, thus leaking it.

Fix it by adding the dso__is_kcore() test to the 'or' group just after
it, the one containing the full fallback code, including freeing the
filename.

Cc: Adrian Hunter 
Cc: David Ahern 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Wang Nan 
Fixes: ee205503f233 ("perf tools: Fix annotation with kcore")
Link: http://lkml.kernel.org/n/tip-qi4rpjq8yo6myvg99kkgt0xz@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo