ukui/kernel
0
0
Fork 0
mirror of https://github.com/ukui/kernel.git synced 2026-03-09 10:07:04 -07:00
Code Issues Packages Projects Releases Wiki Activity
560,538 Commits 1 Branch 0 Tags
65f0f686de9fcbad7dadcedae94de77ab8b558b7
Commit Graph

3429 Commits

Author SHA1 Message Date
Wang Nan 421fd0845e perf probe: Verify parameters in two functions 
On kernel with only one out of CONFIG_KPROBE_EVENTS and
CONFIG_UPROBE_EVENTS enabled, 'perf probe -d' causes a segfault because
perf_del_probe_events() calls probe_file__get_events() with a negative
fd.

This patch fixes it by adding parameter validation at the entry of
probe_file__get_events() and probe_file__get_rawlist(). Since they are
both non-static public functions (in .h file), parameter verifying is
required.

v1 -> v2: Verify fd at the head of probe_file__get_rawlist() instead of
          checking at call site (suggested by Masami and Arnaldo at [1,2]).

[1] http://lkml.kernel.org/r/50399556C9727B4D88A595C8584AAB37526048E3@GSjpTKYDCembx32.service.hitachi.net
[2] http://lkml.kernel.org/r/20151105155830.GV13236@kernel.org

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1446803415-83382-1-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
 2015-11-11 18:41:32 -03:00
Arnaldo Carvalho de Melo e87b49116d perf session: Add missing newlines to some pr_err() calls 
Before:

  [acme@zoo linux]$ perf evlist
  WARNING: The perf.data file's data size field is 0 which is unexpected.
  Was the 'perf record' command properly terminated?
  non matching sample_type[acme@zoo linux]$

After:

  [acme@zoo linux]$ perf evlist
  WARNING: The perf.data file's data size field is 0 which is unexpected.
  Was the 'perf record' command properly terminated?
  non matching sample_type
  [acme@zoo linux]$

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-wscok3a2s7yrj8156oc2r6qe@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
 2015-11-11 18:41:31 -03:00
Michael Petlan 4a4c03c1bb perf annotate: Support full source file paths for srcline fix 
The --full-paths option did not show the full source file paths in the 'perf
annotate' tool, because the value of the option was not propagated into the
related functions.

With this patch the value of the --full-paths option is known to the function
that composes the srcline string, so it prints the full path when necessary.

Committer Note:

This affects annotate when the --print-line option is used:

  # perf annotate -h 2>&1 | grep print-line
      -l, --print-line      print matching source lines (may be slow)

Looking just at the lines that should be affected by this change:

Before:

  # perf annotate --print-line --full-paths --stdio fput | grep '\.[ch]:[0-9]\+'
     94.44 atomic64_64.h:114
      5.56 file_table.c:265
   file_table.c:265    5.56 :	  ffffffff81219a00:       callq  ffffffff81769360 <__fentry__>
   atomic64_64.h:114   94.44 :	  ffffffff81219a05:       lock decq 0x38(%rdi)

After:

  # perf annotate --print-line --full-paths --stdio fput | grep '\.[ch]:[0-9]\+'
     94.44 /home/git/linux/arch/x86/include/asm/atomic64_64.h:114
      5.56 /home/git/linux/fs/file_table.c:265
   /home/git/linux/fs/file_table.c:265    5.56 :	  ffffffff81219a00:       callq  ffffffff81769360 <__fentry__>
   /home/git/linux/arch/x86/include/asm/atomic64_64.h:114   94.44 :	  ffffffff81219a05:       lock decq 0x38(%rdi)
  #

Signed-off-by: Michael Petlan <mpetlan@redhat.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Link: http://permalink.gmane.org/gmane.linux.kernel.perf.user/2365
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
 2015-11-11 18:41:30 -03:00
Wang Nan ba1fae431e perf test: Add 'perf test BPF' 
This patch adds BPF testcase for testing BPF event filtering.

By utilizing the result of 'perf test LLVM', this patch compiles the
eBPF sample program then test its ability. The BPF script in 'perf test
LLVM' lets only 50% samples generated by epoll_pwait() to be captured.
This patch runs that system call for 111 times, so the result should
contain 56 samples.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1446817783-86722-8-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
 2015-11-06 17:50:03 -03:00
Wang Nan d3e0ce3930 perf bpf: Improve BPF related error messages 
A series of bpf loader related error codes were introduced to help error
reporting. Functions were improved to return these new error codes.

Functions which return pointers were adjusted to encode error codes into
return value using the ERR_PTR() interface.

bpf_loader_strerror() was improved to convert these error messages to
strings. It checks the error codes and calls libbpf_strerror() and
strerror_r() accordingly, so caller don't need to consider checking the
range of the error code.

In bpf__strerror_load(), print kernel version of running kernel and the
object's 'version' section to notify user how to fix his/her program.

v1 -> v2:
 Use macro for error code.

 Fetch error message based on array index, eliminate for-loop.

 Print version strings.

Before:

  # perf record -e ./test_kversion_nomatch_program.o sleep 1
  event syntax error: './test_kversion_nomatch_program.o'
                       \___ Failed to load program: Validate your program and check 'license'/'version' sections in your object
  SKIP

  After:

  # perf record -e ./test_kversion_nomatch_program.o ls
  event syntax error: './test_kversion_nomatch_program.o'
                       \___ 'version' (4.4.0) doesn't match running kernel (4.3.0)
  SKIP

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1446818289-87444-1-git-send-email-wangnan0@huawei.com
[ Add 'static inline' to bpf__strerror_prepare_load() when LIBBPF is disabled ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
 2015-11-06 17:14:20 -03:00
Wang Nan 07bc5c699a perf tools: Make fetch_kernel_version() publicly available 
There are 2 places in llvm-utils.c which find kernel version information
through uname. This patch extracts the uname related code into a
fetch_kernel_version() function and puts it into util.h so it can be
reused.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1446818135-87310-1-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
 2015-11-06 15:57:18 -03:00
Wang Nan 6371ca3b54 bpf tools: Improve libbpf error reporting 
In this patch, a series of libbpf specific error numbers and
libbpf_strerror() are introduced to help reporting errors.

Functions are updated to pass correct the error number through the
CHECK_ERR() macro.

All users of bpf_object__open{_buffer}() and bpf_program__title() in
perf are modified accordingly. In addition, due to the error codes
changing, bpf__strerror_load() is also modified to use them.

bpf__strerror_head() is also changed accordingly so it can parse libbpf
errors. bpf_loader_strerror() is introduced for that purpose, and will
be improved by the following patch.

load_program() is improved not to dump log buffer if it is empty. log
buffer is also used to deduce whether the error was caused by an invalid
program or other problem.

v1 -> v2:

 - Using macro for error code.

 - Fetch error message based on array index, eliminate for-loop.

 - Use log buffer to detect the reason of failure. 3 new error code
   are introduced to replace LIBBPF_ERRNO__LOAD.

In v1:

  # perf record -e ./test_ill_program.o ls
  event syntax error: './test_ill_program.o'
                       \___ Failed to load program: Validate your program and check 'license'/'version' sections in your object
  SKIP

  # perf record -e ./test_kversion_nomatch_program.o ls
  event syntax error: './test_kversion_nomatch_program.o'
                       \___ Failed to load program: Validate your program and check 'license'/'version' sections in your object
  SKIP

  # perf record -e ./test_big_program.o ls
  event syntax error: './test_big_program.o'
                       \___ Failed to load program: Validate your program and check 'license'/'version' sections in your object
  SKIP

  In v2:

  # perf record -e ./test_ill_program.o ls
  event syntax error: './test_ill_program.o'
                       \___ Kernel verifier blocks program loading
  SKIP

  # perf record -e ./test_kversion_nomatch_program.o
  event syntax error: './test_kversion_nomatch_program.o'
                       \___ Incorrect kernel version
  SKIP
  (Will be further improved by following patches)

  # perf record -e ./test_big_program.o
  event syntax error: './test_big_program.o'
                       \___ Program too big
  SKIP

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1446817783-86722-2-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
 2015-11-06 15:52:41 -03:00
Masami Hiramatsu 0a62f6869f perf probe: Cleanup find_perf_probe_point_from_map to reduce redundancy 
In find_perf_probe_point_from_map(), the 'ret' variable is initialized
with -ENOENT but overwritten by the return code of
kernel_get_symbol_address_by_name(), and after that it is re-initialized
with -ENOENT again.

Setting ret=-ENOENT twice looks a bit redundant. This avoids the
overwriting and just returns -ENOENT if some error happens to simplify
the code.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: Zefan Li <lizefan@huawei.com>
Link: http://lkml.kernel.org/n/tip-ufp1zgbktzmttcputozneomd@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
 2015-11-06 10:47:33 -03:00
Andi Kleen 62ec9b3f02 perf annotate: Inform the user about objdump failures in --stdio 
When the browser fails to annotate it is difficult for users to find out
what went wrong.

Add some errors for objdump failures that are displayed in the UI.

Note it would be even better to handle these errors smarter, like
falling back to the binary when the debug info is somehow corrupted. But
for now just giving a better error is an improvement.

Committer note:

This works for --stdio, where errors just scroll by the screen:

  # perf annotate --stdio intel_idle
  Failure running objdump  --start-address=0xffffffff81418290 --stop-address=0xffffffff814183ae -l -d --no-show-raw -S -C /root/.debug/.build-id/28/2777c262e6b3c0451375163c9a81c893218ab1 2>/dev/null|grep -v /root/.debug/.build-id/28/2777c262e6b3c0451375163c9a81c893218ab1|expand
   Percent |      Source code & Disassembly of vmlinux for cycles:pp
  ------------------------------------------------------------------

And with that one can use that command line to try to find out more about what
happened instead of getting a blank screen, an improvement.

We need tho to improve this further to get it to work with other UIs, like
--tui and --gtk, where it continues showing a blank screen, no messages, as
the pr_err() used is enough just for --stdio.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/1446779167-18949-1-git-send-email-andi@firstfloor.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
 2015-11-06 10:20:48 -03:00
Wang Nan 98d3b258ed perf tools: Fix find_perf_probe_point_from_map() which incorrectly returns success 
It is possible that find_perf_probe_point_from_map() fails to find a
symbol but still returns 0 because of an small error when coding:
find_perf_probe_point_from_map() set 'ret' to error code at first, but
also use it to hold return value of kernel_get_symbol_address_by_name().

This patch resets 'ret' to error even kernel_get_symbol_address_by_name()
success, so if !sym, the whole function returns error correctly.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1446729565-27592-3-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
 2015-11-05 12:47:52 -03:00
Wang Nan 4a4f66a1a7 perf llvm: Pass LINUX_VERSION_CODE to BPF program when compiling 
Arnaldo suggests to make LINUX_VERSION_CODE works like __func__ and
__FILE__ so user don't need to care setting right linux version too
much. In this patch, perf llvm transfers LINUX_VERSION_CODE macro
through clang cmdline.

[1] http://lkml.kernel.org/r/20151029223744.GK2923@kernel.org

Committer notes:

Before, forgetting to update the version:

  # uname -r
  4.3.0-rc1+
  # cat bpf.c
  __attribute__((section("fork=_do_fork"), used))
  int fork(void *ctx)
  {
          return 1;
  }

  char _license[] __attribute__((section("license"), used)) = "GPL";
  int _version __attribute__((section("version"), used)) = 0x40200;
  #
  # perf record -e bpf.c sleep 1
  event syntax error: 'bpf.c'
                       \___ Invalid argument: Are you root and runing a CONFIG_BPF_SYSCALL kernel?

  (add -v to see detail)
  Run 'perf list' for a list of valid events

   Usage: perf record [<options>] [<command>]
      or: perf record [<options>] -- <command> [<options>]

      -e, --event <event>   event selector. use 'perf list' to list available events
 #

After:

  # grep version bpf.c
  int _version __attribute__((section("version"), used)) = LINUX_VERSION_CODE;
  # perf record -e bpf.c sleep 1
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.017 MB perf.data ]
  # perf evlist -v
  perf_bpf_probe:fork: type: 2, size: 112, config: 0x5ee, { sample_period,
  sample_freq }: 1, sample_type: IP|TID|TIME|CPU|PERIOD|RAW, disabled: 1,
  inherit: 1, mmap: 1, comm: 1, enable_on_exec: 1, task: 1, sample_id_all:
  1, exclude_guest: 1, mmap2: 1, comm_exec: 1
  #

Suggested-and-Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1446636007-239722-3-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
 2015-11-05 12:47:50 -03:00
Wang Nan 59f41af980 perf llvm: Pass number of configured CPUs to clang compiler 
This patch introduces a new macro "__NR_CPUS__" to perf's embedded clang
compiler, which represent the number of configured CPUs in this system.
BPF programs can use this macro to create a map with the same number of
system CPUs. For example:

 struct bpf_map_def SEC("maps") pmu_map = {
     .type = BPF_MAP_TYPE_PERF_EVENT_ARRAY,
     .key_size = sizeof(int),
     .value_size = sizeof(u32),
     .max_entries = __NR_CPUS__,
 };

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1446636007-239722-2-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
 2015-11-05 12:47:02 -03:00
Jiri Olsa cb8382e058 perf tools: Insert split maps correctly into origin group 
When new maps are cloned out of split map they are added into origin
map's group, but their groups pointer is not updated.

This could lead to a segfault, because map->groups is expected to be
always set as reported by Markus:

  __map__is_kernel (map=map@entry=0x1abb7a0) at util/map.c:238
  238             return __machine__kernel_map(map->groups->machine, map->type) =
  (gdb) bt
  #0  __map__is_kernel (map=map@entry=0x1abb7a0) at util/map.c:238
  #1  0x00000000004393e4 in symbol_filter (map=map@entry=0x1abb7a0, sym=sym@entry
  #2  0x00000000004fcd4d in dso__load_sym (dso=dso@entry=0x166dae0, map=map@entry
  #3  0x00000000004a64e0 in dso__load (dso=0x166dae0, map=map@entry=0x1abb7a0, fi
  #4  0x00000000004b941f in map__load (filter=0x4393c0 <symbol_filter>, map=<opti
  #5  map__find_symbol (map=0x1abb7a0, addr=40188, filter=0x4393c0 <symbol_filter
  ...

Adding __map_groups__insert function to add map into groups together
with map->groups pointer update. It takes no lock as opposed to existing
map_groups__insert, as maps__fixup_overlappings(), where it is being
called, already has the necessary lock held.

Using __map_groups__insert to add new maps after map split.

Reported-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20151104140811.GA32664@krava.brq.redhat.com
Fixes: cfc5acd4c8 ("perf top: Filter symbols based on __map__is_kernel(map)")
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
 2015-11-05 11:39:38 -03:00
Andi Kleen 4579ecc8b3 perf stat: Move sw clock metrics printout to stat-shadow 
The sw clock metrics printing was missed in the earlier move to
stat-shadow of all the other metric printouts. Move it too.

v2: Fix metrics printing in this version to make bisect safe.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: http://lkml.kernel.org/r/1446515428-7450-2-git-send-email-andi@firstfloor.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
 2015-11-04 15:11:41 -03:00
Wang Nan 7a0119468c perf bpf: Mute libbpf when '-v' not set 
According to [1], libbpf should be muted. This patch reset info and
warning message level to ensure libbpf doesn't output anything even
if error happened.

[1] http://lkml.kernel.org/r/20151020151255.GF5119@kernel.org

Committer note:

Before:

Testing it with an incompatible kernel version in the .c file that
generated foo.o:

  [root@zoo ~]# perf record -e /tmp/foo.o sleep 1
  libbpf: load bpf program failed: Invalid argument
  libbpf: -- BEGIN DUMP LOG ---
  libbpf:

  libbpf: -- END LOG --
  libbpf: failed to load program 'fork=_do_fork'
  libbpf: failed to load object '/tmp/foo.o'
  event syntax error: '/tmp/foo.o'
                       \___ Invalid argument: Are you root and runing a CONFIG_BPF_SYSCALL kernel?

  (add -v to see detail)
  Run 'perf list' for a list of valid events

   Usage: perf record [<options>] [<command>]
      or: perf record [<options>] -- <command> [<options>]

      -e, --event <event>   event selector. use 'perf list' to list available events
  [root@zoo ~]#

After:

  [root@zoo ~]# perf record -e /tmp/foo.o sleep 1
  event syntax error: '/tmp/foo.o'
                       \___ Invalid argument: Are you root and runing a CONFIG_BPF_SYSCALL kernel?

  (add -v to see detail)
  Run 'perf list' for a list of valid events

   Usage: perf record [<options>] [<command>]
      or: perf record [<options>] -- <command> [<options>]

      -e, --event <event>   event selector. use 'perf list' to list available events
  [root@zoo ~]#

This, BTW, need fixing to emit a proper message by validating the
version in the foo.o "version" ELF section against the running kernel,
warning the user instead of asking the kernel to load a binary that it
will refuse due to unmatching kernel version.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1446547486-229499-3-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
 2015-11-03 12:06:04 -03:00
Rabin Vincent 7ed4915ad6 perf unwind: Pass symbol source to libunwind 
Even if --symfs is used to point to the debug binaries, we send in the
non-debug filenames to libunwind, which leads to libunwind not finding
the debug frame.  Fix this by preferring the file in --symfs, if it is
available.

Signed-off-by: Rabin Vincent <rabin.vincent@axis.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Rabin Vincent <rabinv@axis.com>
Link: http://lkml.kernel.org/r/1446104978-26429-1-git-send-email-rabin.vincent@axis.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
 2015-10-29 17:48:38 -03:00
Wang Nan d509db0473 perf tools: Compile scriptlets to BPF objects when passing '.c' to --event 
This patch provides infrastructure for passing source files to --event
directly using:

 # perf record --event bpf-file.c command

This patch does following works:

 1) Allow passing '.c' file to '--event'. parse_events_load_bpf() is
    expanded to allow caller tell it whether the passed file is source
    file or object.

 2) llvm__compile_bpf() is called to compile the '.c' file, the result
    is saved into memory. Use bpf_object__open_buffer() to load the
    in-memory object.

Introduces a bpf-script-example.c so we can manually test it:

 # perf record --clang-opt "-DLINUX_VERSION_CODE=0x40200" --event ./bpf-script-example.c sleep 1

Note that '--clang-opt' must put before '--event'.

Futher patches will merge it into a testcase so can be tested automatically.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: David Ahern <dsahern@gmail.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kaixu Xia <xiakaixu@huawei.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1444826502-49291-10-git-send-email-wangnan0@huawei.com
Signed-off-by: He Kuang <hekuang@huawei.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
 2015-10-29 17:16:23 -03:00
Wang Nan 1f45b1d490 perf bpf: Attach eBPF filter to perf event 
This is the final patch which makes basic BPF filter work. After
applying this patch, users are allowed to use BPF filter like:

 # perf record --event ./hello_world.o ls

A bpf_fd field is appended to 'struct evsel', and setup during the
callback function add_bpf_event() for each 'probe_trace_event'.

PERF_EVENT_IOC_SET_BPF ioctl is used to attach eBPF program to a newly
created perf event. The file descriptor of the eBPF program is passed to
perf record using previous patches, and stored into evsel->bpf_fd.

It is possible that different perf event are created for one kprobe
events for different CPUs. In this case, when trying to call the ioctl,
EEXIST will be return. This patch doesn't treat it as an error.

Committer note:

The bpf proggie used so far:

  __attribute__((section("fork=_do_fork"), used))
  int fork(void *ctx)
  {
	  return 0;
  }

  char _license[] __attribute__((section("license"), used)) = "GPL";
  int _version __attribute__((section("version"), used)) = 0x40300;

failed to produce any samples, even with forks happening and it being
running in system wide mode.

That is because now the filter is being associated, and the code above
always returns zero, meaning that all forks will be probed but filtered
away ;-/

Change it to 'return 1;' instead and after that:

  # trace --no-syscalls --event /tmp/foo.o
     0.000 perf_bpf_probe:fork:(ffffffff8109be30))
     2.333 perf_bpf_probe:fork:(ffffffff8109be30))
     3.725 perf_bpf_probe:fork:(ffffffff8109be30))
     4.550 perf_bpf_probe:fork:(ffffffff8109be30))
  ^C#

And it works with all tools, including 'perf trace'.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: David Ahern <dsahern@gmail.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kaixu Xia <xiakaixu@huawei.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1444826502-49291-8-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
 2015-10-29 17:16:22 -03:00
Wang Nan 4edf30e39e perf bpf: Collect perf_evsel in BPF object files 
This patch creates a 'struct perf_evsel' for every probe in a BPF object
file(s) and fills 'struct evlist' with them. The previously introduced
dummy event is now removed. After this patch, the following command:

 # perf record --event filter.o ls

Can trace on each of the probes defined in filter.o.

The core of this patch is bpf__foreach_tev(), which calls a callback
function for each 'struct probe_trace_event' event for a bpf program
with each associated file descriptors. The add_bpf_event() callback
creates evsels by calling parse_events_add_tracepoint().

Since bpf-loader.c will not be built if libbpf is turned off, an empty
bpf__foreach_tev() is defined in bpf-loader.h to avoid build errors.

Committer notes:

Before:

  # /tmp/oldperf record --event /tmp/foo.o -a usleep 1
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.198 MB perf.data ]
  # perf evlist
  /tmp/foo.o
  # perf evlist -v
  /tmp/foo.o: type: 1, size: 112, config: 0x9, { sample_period,
  sample_freq }: 4000, sample_type: IP|TID|TIME|CPU|PERIOD, disabled: 1,
  inherit: 1, mmap: 1, comm: 1, freq: 1, task: 1, sample_id_all: 1,
  exclude_guest: 1, mmap2: 1, comm_exec: 1

I.e. we create just the PERF_TYPE_SOFTWARE (type: 1),
PERF_COUNT_SW_DUMMY(config 0x9) event, now, with this patch:

  # perf record --event /tmp/foo.o -a usleep 1
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.210 MB perf.data ]
  # perf evlist -v
  perf_bpf_probe:fork: type: 2, size: 112, config: 0x6bd, { sample_period,
  sample_freq }: 1, sample_type: IP|TID|TIME|CPU|PERIOD|RAW, disabled: 1,
  inherit: 1, mmap: 1, comm: 1, task: 1, sample_id_all: 1, exclude_guest:
  1, mmap2: 1, comm_exec: 1
  #

We now have a PERF_TYPE_SOFTWARE (type: 1), but the config states 0x6bd,
which is how, after setting up the event via the kprobes interface, the
'perf_bpf_probe:fork' event is accessible via the perf_event_open
syscall. This is all transient, as soon as the 'perf record' session
ends, these probes will go away.

To see how it looks like, lets try doing a neverending session, one that
expects a control+C to end:

  # perf record --event /tmp/foo.o -a

So, with that in place, we can use 'perf probe' to see what is in place:

  # perf probe -l
    perf_bpf_probe:fork  (on _do_fork@acme/git/linux/kernel/fork.c)

We also can use debugfs:

  [root@felicio ~]# cat /sys/kernel/debug/tracing/kprobe_events
  p:perf_bpf_probe/fork _text+638512

Ok, now lets stop and see if we got some forks:

  [root@felicio linux]# perf record --event /tmp/foo.o -a
  ^C[ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.325 MB perf.data (111 samples) ]

  [root@felicio linux]# perf script
      sshd  1271 [003] 81797.507678: perf_bpf_probe:fork: (ffffffff8109be30)
      sshd 18309 [000] 81797.524917: perf_bpf_probe:fork: (ffffffff8109be30)
      sshd 18309 [001] 81799.381603: perf_bpf_probe:fork: (ffffffff8109be30)
      sshd 18309 [001] 81799.408635: perf_bpf_probe:fork: (ffffffff8109be30)
  <SNIP>

Sure enough, we have 111 forks :-)

Callchains seems to work as well:

  # perf report --stdio --no-child
  # To display the perf.data header info, please use --header/--header-only options.
  #
  # Total Lost Samples: 0
  #
  # Samples: 562  of event 'perf_bpf_probe:fork'
  # Event count (approx.): 562
  #
  # Overhead  Command   Shared Object     Symbol
  # ........  ........  ................  ............
  #
      44.66%  sh        [kernel.vmlinux]  [k] _do_fork
                    |
                    ---_do_fork
                       entry_SYSCALL_64_fastpath
                       __libc_fork
                       make_child

    26.16%  make      [kernel.vmlinux]  [k] _do_fork
<SNIP>
  #

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: David Ahern <dsahern@gmail.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kaixu Xia <xiakaixu@huawei.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1444826502-49291-7-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
 2015-10-28 13:11:59 -03:00
Wang Nan 1e5e3ee8ff perf tools: Load eBPF object into kernel 
This patch utilizes bpf_object__load() provided by libbpf to load all
objects into kernel.

Committer notes:

Testing it:

When using an incorrect kernel version number, i.e., having this in your
eBPF proggie:

  int _version __attribute__((section("version"), used)) = 0x40100;

For a 4.3.0-rc6+ kernel, say, this happens and needs checking at event
parsing time, to provide a better error report to the user:

  # perf record --event /tmp/foo.o sleep 1
  libbpf: load bpf program failed: Invalid argument
  libbpf: -- BEGIN DUMP LOG ---
  libbpf:

  libbpf: -- END LOG --
  libbpf: failed to load program 'fork=_do_fork'
  libbpf: failed to load object '/tmp/foo.o'
  event syntax error: '/tmp/foo.o'
                       \___ Invalid argument: Are you root and runing a CONFIG_BPF_SYSCALL kernel?

  (add -v to see detail)
  Run 'perf list' for a list of valid events

   Usage: perf record [<options>] [<command>]
      or: perf record [<options>] -- <command> [<options>]

      -e, --event <event>   event selector. use 'perf list' to list available events

If we instead make it match, i.e. use 0x40300 on this v4.3.0-rc6+
kernel, the whole process goes thru:

  # perf record --event /tmp/foo.o -a usleep 1
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.202 MB perf.data ]
  # perf evlist -v
  /tmp/foo.o: type: 1, size: 112, config: 0x9, { sample_period,
  sample_freq }: 4000, sample_type: IP|TID|TIME|CPU|PERIOD, disabled: 1,
  inherit: 1, mmap: 1, comm: 1, freq: 1, task: 1, sample_id_all: 1,
  exclude_guest: 1, mmap2: 1, comm_exec: 1
  #

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: David Ahern <dsahern@gmail.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kaixu Xia <xiakaixu@huawei.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1444826502-49291-6-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
 2015-10-28 13:09:50 -03:00
Wang Nan aa3abf30bb perf tools: Create probe points for BPF programs 
This patch introduces bpf__{un,}probe() functions to enable callers to
create kprobe points based on section names a BPF program. It parses the
section names in the program and creates corresponding 'struct
perf_probe_event' structures. The parse_perf_probe_command() function is
used to do the main parsing work. The resuling 'struct perf_probe_event'
is stored into program private data for further using.

By utilizing the new probing API, this patch creates probe points during
event parsing.

To ensure probe points be removed correctly, register an atexit hook so
even perf quit through exit() bpf__clear() is still called, so probing
points are cleared. Note that bpf_clear() should be registered before
bpf__probe() is called, so failure of bpf__probe() can still trigger
bpf__clear() to remove probe points which are already probed.

strerror style error reporting scaffold is created by this patch.
bpf__strerror_probe() is the first error reporting function in
bpf-loader.c.

Committer note:

Trying it:

To build a test eBPF object file:

I am testing using a script I built from the 'perf test -v LLVM' output:

  $ cat ~/bin/hello-ebpf
  export KERNEL_INC_OPTIONS="-nostdinc -isystem /usr/lib/gcc/x86_64-redhat-linux/4.8.3/include -I/home/acme/git/linux/arch/x86/include -Iarch/x86/include/generated/uapi -Iarch/x86/include/generated -I/home/acme/git/linux/include -Iinclude -I/home/acme/git/linux/arch/x86/include/uapi -Iarch/x86/include/generated/uapi -I/home/acme/git/linux/include/uapi -Iinclude/generated/uapi -include /home/acme/git/linux/include/linux/kconfig.h"
  export WORKING_DIR=/lib/modules/4.2.0/build
  export CLANG_SOURCE=-
  export CLANG_OPTIONS=-xc

  OBJ=/tmp/foo.o
  rm -f $OBJ
  echo '__attribute__((section("fork=do_fork"), used)) int fork(void *ctx) {return 0;} char _license[] __attribute__((section("license"), used)) = "GPL";int _version __attribute__((section("version"), used)) = 0x40100;' | \
  clang -D__KERNEL__ $CLANG_OPTIONS $KERNEL_INC_OPTIONS -Wno-unused-value -Wno-pointer-sign -working-directory $WORKING_DIR -c "$CLANG_SOURCE" -target bpf -O2 -o /tmp/foo.o && file $OBJ

 ---

First asking to put a probe in a function not present in the kernel
(misses the initial _):

  $ perf record --event /tmp/foo.o sleep 1
  Probe point 'do_fork' not found.
  event syntax error: '/tmp/foo.o'
                       \___ You need to check probing points in BPF file

  (add -v to see detail)
  Run 'perf list' for a list of valid events

   Usage: perf record [<options>] [<command>]
      or: perf record [<options>] -- <command> [<options>]

      -e, --event <event>   event selector. use 'perf list' to list available events
  $

 ---

Now, with "__attribute__((section("fork=_do_fork"), used)):

 $ grep _do_fork /proc/kallsyms
 ffffffff81099ab0 T _do_fork
 $ perf record --event /tmp/foo.o sleep 1
 Failed to open kprobe_events: Permission denied
 event syntax error: '/tmp/foo.o'
                      \___ Permission denied

 ---

Cool, we need to provide some better hints, "kprobe_events" is too low
level, one doesn't strictly need to know the precise details of how
these things are put in place, so something that shows the command
needed to fix the permissions would be more helpful.

Lets try as root instead:

  # perf record --event /tmp/foo.o sleep 1
  Lowering default frequency rate to 1000.
  Please consider tweaking /proc/sys/kernel/perf_event_max_sample_rate.
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.013 MB perf.data ]
  # perf evlist
  /tmp/foo.o
  [root@felicio ~]# perf evlist -v
  /tmp/foo.o: type: 1, size: 112, config: 0x9, { sample_period,
  sample_freq }: 1000, sample_type: IP|TID|TIME|PERIOD, disabled: 1,
  inherit: 1, mmap: 1, comm: 1, freq: 1, enable_on_exec: 1, task: 1,
  sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1

 ---

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: David Ahern <dsahern@gmail.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kaixu Xia <xiakaixu@huawei.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1444826502-49291-5-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
 2015-10-28 12:48:13 -03:00
Wang Nan 84c86ca12b perf tools: Enable passing bpf object file to --event 
By introducing new rules in tools/perf/util/parse-events.[ly], this
patch enables 'perf record --event bpf_file.o' to select events by an
eBPF object file. It calls parse_events_load_bpf() to load that file,
which uses bpf__prepare_load() and finally calls bpf_object__open() for
the object files.

After applying this patch, commands like:

 # perf record --event foo.o sleep

become possible.

However, at this point it is unable to link any useful things onto the
evsel list because the creating of probe points and BPF program
attaching have not been implemented.  Before real events are possible to
be extracted, to avoid perf report error because of empty evsel list,
this patch link a dummy evsel. The dummy event related code will be
removed when probing and extracting code is ready.

Commiter notes:

Using it:

  $ ls -la foo.o
  ls: cannot access foo.o: No such file or directory
  $ perf record --event foo.o sleep
  libbpf: failed to open foo.o: No such file or directory
  event syntax error: 'foo.o'
                       \___ BPF object file 'foo.o' is invalid

  (add -v to see detail)
  Run 'perf list' for a list of valid events

   Usage: perf record [<options>] [<command>]
      or: perf record [<options>] -- <command> [<options>]

      -e, --event <event>   event selector. use 'perf list' to list available events
  $

  $ file /tmp/build/perf/perf.o
  /tmp/build/perf/perf.o: ELF 64-bit LSB relocatable, x86-64, version 1 (SYSV), not stripped
  $ perf record --event /tmp/build/perf/perf.o sleep
  libbpf: /tmp/build/perf/perf.o is not an eBPF object file
  event syntax error: '/tmp/build/perf/perf.o'
                       \___ BPF object file '/tmp/build/perf/perf.o' is invalid

  (add -v to see detail)
  Run 'perf list' for a list of valid events

   Usage: perf record [<options>] [<command>]
      or: perf record [<options>] -- <command> [<options>]

      -e, --event <event>   event selector. use 'perf list' to list available events
  $

  $ file /tmp/foo.o
  /tmp/foo.o: ELF 64-bit LSB relocatable, no machine, version 1 (SYSV), not stripped
  $ perf record --event /tmp/foo.o sleep 1
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.013 MB perf.data ]
  $ perf evlist
  /tmp/foo.o
  $ perf evlist  -v
  /tmp/foo.o: type: 1, size: 112, config: 0x9, { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|PERIOD, disabled: 1, inherit: 1, mmap: 1, comm: 1, freq: 1, enable_on_exec: 1, task: 1, sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1
  $

So, type 1 is PERF_TYPE_SOFTWARE, config 0x9 is PERF_COUNT_SW_DUMMY, ok.

  $ perf report --stdio
  Error:
  The perf.data file has no samples!
  # To display the perf.data header info, please use --header/--header-only options.
  #
  $

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: David Ahern <dsahern@gmail.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kaixu Xia <xiakaixu@huawei.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1444826502-49291-4-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
 2015-10-28 12:48:12 -03:00
Wang Nan 69d262a93a perf ebpf: Add the libbpf glue 
The 'bpf-loader.[ch]' files are introduced in this patch. Which will be
the interface between perf and libbpf. bpf__prepare_load() resides in
bpf-loader.c. Following patches will enrich these two files.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: David Ahern <dsahern@gmail.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kaixu Xia <xiakaixu@huawei.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1444826502-49291-3-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
 2015-10-28 12:48:12 -03:00
Jiri Olsa 443f8c75e8 perf symbols: Fix endless loop in dso__split_kallsyms_for_kcore 
Currently we split symbols based on the map comparison, but symbols are stored
within dso objects and maps could point into same dso objects (kernel maps).

Hence we could end up changing rbtree we are currently iterating and mess it
up. It's easily reproduced on s390x by running:

  $ perf record -a -- sleep 3
  $ perf buildid-list -i perf.data --with-hits

The fix is to compare dso objects instead.

Reported-by: Michael Petlan <mpetlan@redhat.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20151026135130.GA26003@krava.brq.redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
 2015-10-28 11:19:30 -03:00
Wang Nan 374ce938aa perf tools: Enable pre-event inherit setting by config terms 
This patch allows perf record setting event's attr.inherit bit by
config terms like:

  # perf record -e cycles/no-inherit/ ...
  # perf record -e cycles/inherit/ ...

So user can control inherit bit for each event separately.

In following example, a.out fork()s in main then do some complex
CPU intensive computations in both of its children.

Basic result with and without inherit:

  # perf record -e cycles -e instructions ./a.out
  [ perf record: Woken up 9 times to write data ]
  [ perf record: Captured and wrote 2.205 MB perf.data (47920 samples) ]
  # perf report --stdio
  # ...
  # Samples: 23K of event 'cycles'
  # Event count (approx.): 23641752891
  ...
  # Samples: 24K of event 'instructions'
  # Event count (approx.): 30428312415

  # perf record -i -e cycles -e instructions ./a.out
  [ perf record: Woken up 5 times to write data ]
  [ perf record: Captured and wrote 1.111 MB perf.data (24019 samples) ]
  ...
  # Samples: 12K of event 'cycles'
  # Event count (approx.): 11699501775
  ...
  # Samples: 12K of event 'instructions'
  # Event count (approx.): 15058023559

Cancel inherit for one event when globally enable:

  # perf record -e cycles/no-inherit/ -e instructions ./a.out
  [ perf record: Woken up 7 times to write data ]
  [ perf record: Captured and wrote 1.660 MB perf.data (36004 samples) ]
  ...
  # Samples: 12K of event 'cycles/no-inherit/'
  # Event count (approx.): 11895759282
 ...
  # Samples: 24K of event 'instructions'
  # Event count (approx.): 30668000441

Enable inherit for one event when globally disable:

  # perf record -i -e cycles/inherit/ -e instructions ./a.out
  [ perf record: Woken up 7 times to write data ]
  [ perf record: Captured and wrote 1.654 MB perf.data (35868 samples) ]
  ...
  # Samples: 23K of event 'cycles/inherit/'
  # Event count (approx.): 23285400229
  ...
  # Samples: 11K of event 'instructions'
  # Event count (approx.): 14969050259

Committer note:

One can check if the bit was set, in addition to seeing the result in
the perf.data file size as above by doing one of:

  # perf record -e cycles -e instructions -a usleep 1
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.911 MB perf.data (63 samples) ]
  # perf evlist -v
  cycles: size: 112, { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|ID|CPU|PERIOD, read_format: ID, disabled: 1, inherit: 1, mmap: 1, comm: 1, freq: 1, task: 1, sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1
  instructions: size: 112, config: 0x1, { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|ID|CPU|PERIOD, read_format: ID, disabled: 1, inherit: 1, freq: 1, sample_id_all: 1, exclude_guest: 1
  #

So, the inherit bit was set in both, now, if we disable it globally using
--no-inherit:

  # perf record --no-inherit -e cycles -e instructions -a usleep 1
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.910 MB perf.data (56 samples) ]
  # perf evlist -v
  cycles: size: 112, { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|ID|CPU|PERIOD, read_format: ID, disabled: 1, mmap: 1, comm: 1, freq: 1, task: 1, sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1
  instructions: size: 112, config: 0x1, { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|ID|CPU|PERIOD, read_format: ID, disabled: 1, freq: 1, sample_id_all: 1, exclude_guest: 1

No inherit bit set, then disabling it and setting just on the cycles event:

  # perf record --no-inherit -e cycles/inherit/ -e instructions -a usleep 1
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.909 MB perf.data (48 samples) ]
  # perf evlist -v
  cycles/inherit/: size: 112, { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|ID|CPU|PERIOD, read_format: ID, disabled: 1, inherit: 1, mmap: 1, comm: 1, freq: 1, task: 1, sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1
  instructions: size: 112, config: 0x1, { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|ID|CPU|PERIOD, read_format: ID, disabled: 1, freq: 1, sample_id_all: 1, exclude_guest: 1
  #

We can see it as well in by using a more verbose level of debug messages in
the tool that sets up the perf_event_attr, 'perf record' in this case:

  [root@zoo ~]# perf record -vv --no-inherit -e cycles/inherit/ -e instructions -a usleep 1
  ------------------------------------------------------------
  perf_event_attr:
    size                             112
    { sample_period, sample_freq }   4000
    sample_type                      IP|TID|TIME|ID|CPU|PERIOD
    read_format                      ID
    disabled                         1
    inherit                          1
    mmap                             1
    comm                             1
    freq                             1
    task                             1
    sample_id_all                    1
    exclude_guest                    1
    mmap2                            1
    comm_exec                        1
  ------------------------------------------------------------
  sys_perf_event_open: pid -1  cpu 0  group_fd -1  flags 0x8
  sys_perf_event_open: pid -1  cpu 1  group_fd -1  flags 0x8
  sys_perf_event_open: pid -1  cpu 2  group_fd -1  flags 0x8
  sys_perf_event_open: pid -1  cpu 3  group_fd -1  flags 0x8
  ------------------------------------------------------------
  perf_event_attr:
    size                             112
    config                           0x1
    { sample_period, sample_freq }   4000
    sample_type                      IP|TID|TIME|ID|CPU|PERIOD
    read_format                      ID
    disabled                         1
    freq                             1
    sample_id_all                    1
    exclude_guest                    1
  ------------------------------------------------------------
  sys_perf_event_open: pid -1  cpu 0  group_fd -1  flags 0x8

<SNIP>

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1446029705-199659-2-git-send-email-wangnan0@huawei.com
[ s/u64/bool/ for the perf_evsel_config_term inherit field - jolsa]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
 2015-10-28 11:19:16 -03:00