linux-toradex.git/tools/lib/api/fs, branch v4.11-rc3

perf sdt: Show proper hint when event not yet in place via 'perf probe'

2017-02-08T12:28:54+00:00

All events from 'perf list', except SDT events, can be directly recorded
with 'perf record'. But, the flow is little different for SDT events.

Probe points for SDT event needs to be created using 'perf probe' before
recording it using 'perf record'.

Perf shows misleading hint when a user tries to record SDT event without
first creating a probe point. Show proper hint there.

Before patch:

  $ perf record -a -e sdt_glib:idle__add
    event syntax error: 'sdt_glib:idle__add'
                         \___ unknown tracepoint

    Error: File /sys/kernel/debug/tracing/events/sdt_glib/idle__add not found.
    Hint:  Perhaps this kernel misses some CONFIG_ setting to enable this feature?.
    ...

After patch:

  $ perf record -a -e sdt_glib:idle__add
    event syntax error: 'sdt_glib:idle__add'
                         \___ unknown tracepoint

    Error: File /sys/kernel/debug/tracing/events/sdt_glib/idle__add not found.
    Hint:  SDT event cannot be directly recorded on.
           Please first use 'perf probe sdt_glib:idle__add' before recording it.
    ...

  $ perf probe sdt_glib:idle__add
    Added new event:
      sdt_glib:idle__add   (on %idle__add in /usr/lib64/libglib-2.0.so.0.5000.2)

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

        perf record -e sdt_glib:idle__add -aR sleep 1

  $ perf record -a -e sdt_glib:idle__add
    [ perf record: Woken up 1 times to write data ]
    [ perf record: Captured and wrote 0.175 MB perf.data ]

Suggested-and-Acked-by: Ingo Molnar 
Signed-off-by: Ravi Bangoria 
Tested-by: Arnaldo Carvalho de Melo 
Acked-by: Masami Hiramatsu 
Cc: Alexander Shishkin 
Cc: Alexis Berlemont 
Cc: Madhavan Srinivasan 
Cc: Michael Ellerman 
Cc: Naveen N. Rao 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/20170203102642.17258-1-ravi.bangoria@linux.vnet.ibm.com
[ s/Please use/Please first use/ and break the Hint line in two ]
Signed-off-by: Arnaldo Carvalho de Melo

tools lib api fs: Add bpf_fs filesystem detector

2017-01-31T19:20:07+00:00

Allow mounting of the BPF filesystem at /sys/fs/bpf.

Signed-off-by: Joe Stringer 
Cc: Alexei Starovoitov 
Cc: Daniel Borkmann 
Cc: Wang Nan 
Cc: netdev@vger.kernel.org
Link: http://lkml.kernel.org/r/20170126212001.14103-6-joe@ovn.org
Signed-off-by: Arnaldo Carvalho de Melo

tools lib api fs: Add hugetlbfs filesystem detector

2016-09-08T15:34:43+00:00

Detect hugetlbfs. hugetlbfs__mountpoint() will be used during recording
to help identifying hugetlb mmaps: which should be recognized as anon
mapping.

Signed-off-by: Wang Nan 
Reviewed-by: Nilay Vaish 
Cc: He Kuang 
Cc: Hou Pengyang 
Cc: Zefan Li 
Link: http://lkml.kernel.org/r/1473137909-142064-3-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo

tools lib api fs: Use base 0 in filename__read_ull

2016-07-15T16:38:05+00:00

By using 0 for base, the strtoull() detects the base automatically (see
'man strtoull').

ATM we have just one user of this function, the cpu__get_max_freq
function reading the "cpuinfo_max_freq" sysfs file. It should not get
affected by this change.

Committer note:

This change seems motivated by this discussion:

"[PATCH] [RFC V1]s390/perf: fix 'start' address of module's map"
http://lkml.kernel.org/r/20160711120155.GA29929@krava

I.e. this patches paves the way for filename__read_ull() to be used in a
S/390 related fix.

Signed-off-by: Jiri Olsa 
Cc: David Ahern 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Songshan Gong 
Link: http://lkml.kernel.org/r/1468567797-27564-4-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

tools lib api fs: Use str_error_r()

2016-07-12T18:20:29+00:00

To make it portable to non-glibc systems, that follow the XSI variant
instead of the GNU specific one that gets in place when _GNU_SOURCE is
defined.

Cc: Adrian Hunter 
Cc: David Ahern 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Steven Rostedt 
Cc: Wang Nan 
Link: http://lkml.kernel.org/n/tip-mixgnh3iyajuqogn2opsocdy@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

tools lib api fs: Add helper to read string from procfs file

2016-04-26T16:15:00+00:00

To read things like /proc/self/comm.

Cc: Adrian Hunter 
Cc: Borislav Petkov 
Cc: David Ahern 
Cc: Jiri Olsa 
Cc: Milian Wolff 
Cc: Namhyung Kim 
Cc: Wang Nan 
Link: http://lkml.kernel.org/n/tip-ztpkbmseidt0hq2psr46o0h9@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

tools lib api fs: Add sysfs__read_str function

2016-02-16T20:12:57+00:00

Adding sysfs__read_str function to ease up reading string files from
sysfs. New interface is:

  int sysfs__read_str(const char *entry, char **buf, size_t *sizep);

Signed-off-by: Jiri Olsa 
Cc: David Ahern 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1455465826-8426-4-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

tools lib api fs: Adopt filename__read_str from perf

2016-02-16T20:12:56+00:00

We already moved similar functions in here, also it'll be useful for
sysfs__read_str addition in following patch.

Signed-off-by: Jiri Olsa 
Cc: David Ahern 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1455465826-8426-3-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

tools lib api fs: No need to use PATH_MAX + 1

2015-10-05T19:12:09+00:00

Because there's no point, PATH_MAX is big enough.

Signed-off-by: Jiri Olsa 
Cc: David Ahern 
Cc: Don Zickus 
Cc: Kan Liang 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1444068369-20978-2-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

tools lib api fs: Store tracing mountpoint for better error message

2015-09-28T18:50:54+00:00

Storing the actual tracing path mountpoint to display correct
error message hint ('Hint:' line). The error hint rediscovers
mountpoints, but it could be different from what we actually
used in tracing path.

Before we'd display debugfs mount even though tracefs was used:
  $ perf record -e sched:sched_krava ls
  event syntax error: 'sched:sched_krava'
                       \___ can't access trace events

  Error:  No permissions to read /sys/kernel/debug/tracing/events/sched/sched_krava
  Hint:   Try 'sudo mount -o remount,mode=755 /sys/kernel/debug'
  ...

After this change, correct mountpoint is displayed:
  $ perf record -e sched:sched_krava ls
  event syntax error: 'sched:sched_krava'
                       \___ can't access trace events

  Error:  No permissions to read /sys/kernel/debug/tracing/events/sched/sched_krava
  Hint:   Try 'sudo mount -o remount,mode=755 /sys/kernel/debug/tracing'
  ...

Signed-off-by: Jiri Olsa 
Cc: David Ahern 
Cc: Matt Fleming 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Raphael Beamonte 
Link: http://lkml.kernel.org/r/1442674027-19427-1-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo