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  1. 13 5月, 2016 3 次提交
    • A
      perf stat: Fallback to user only counters when perf_event_paranoid > 1 · 42ef8a78
      由 Arnaldo Carvalho de Melo 提交于 
      After 0161028b ("perf/core: Change the default paranoia level to 2")
'perf stat' fails for users without CAP_SYS_ADMIN, so just use
'perf_evsel__fallback()' to have the same behaviour as 'perf record',
i.e. set perf_event_attr.exclude_kernel to 1.

Now:

  [acme@jouet linux]$ perf stat usleep 1

   Performance counter stats for 'usleep 1':

          0.352536      task-clock:u (msec)  #   0.423 CPUs utilized
                 0      context-switches:u   #   0.000 K/sec
                 0      cpu-migrations:u     #   0.000 K/sec
                49      page-faults:u        #   0.139 M/sec
           309,407      cycles:u             #   0.878 GHz
           243,791      instructions:u       #   0.79  insn per cycle
            49,622      branches:u           # 140.757 M/sec
             3,884      branch-misses:u      #   7.83% of all branches

       0.000834174 seconds time elapsed

  [acme@jouet linux]$
Reported-by: NIngo Molnar <mingo@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-b20jmx4dxt5hpaa9t2rroi0o@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      42ef8a78
    • A
      perf evsel: Handle EACCESS + perf_event_paranoid=2 in fallback() · 08094828
      由 Arnaldo Carvalho de Melo 提交于 
      Now with the default for the kernel.perf_event_paranoid sysctl being 2 [1]
we need to fall back to :u, i.e. to set perf_event_attr.exclude_kernel
to 1.

Before:

  [acme@jouet linux]$ perf record usleep 1
  Error:
  You may not have permission to collect stats.

  Consider tweaking /proc/sys/kernel/perf_event_paranoid,
  which controls use of the performance events system by
  unprivileged users (without CAP_SYS_ADMIN).

  The current value is 2:

    -1: Allow use of (almost) all events by all users
  >= 0: Disallow raw tracepoint access by users without CAP_IOC_LOCK
  >= 1: Disallow CPU event access by users without CAP_SYS_ADMIN
  >= 2: Disallow kernel profiling by users without CAP_SYS_ADMIN
  [acme@jouet linux]$

After:

  [acme@jouet linux]$ perf record usleep 1
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.016 MB perf.data (7 samples) ]
  [acme@jouet linux]$ perf evlist
  cycles:u
  [acme@jouet linux]$ perf evlist -v
  cycles:u: size: 112, { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|PERIOD, disabled: 1, inherit: 1, exclude_kernel: 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
  [acme@jouet linux]$

And if the user turns on verbose mode, an explanation will appear:

  [acme@jouet linux]$ perf record -v usleep 1
  Warning:
  kernel.perf_event_paranoid=2, trying to fall back to excluding kernel samples
  mmap size 528384B
  [ perf record: Woken up 1 times to write data ]
  Looking at the vmlinux_path (8 entries long)
  Using /lib/modules/4.6.0-rc7+/build/vmlinux for symbols
  [ perf record: Captured and wrote 0.016 MB perf.data (7 samples) ]
  [acme@jouet linux]$

[1] 0161028b ("perf/core: Change the default paranoia level to 2")
Reported-by: NIngo Molnar <mingo@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-b20jmx4dxt5hpaa9t2rroi0o@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      08094828
    • A
      perf evsel: Improve EPERM error handling in open_strerror() · 7d173913
      由 Arnaldo Carvalho de Melo 提交于 
      We were showing a hardcoded default value for the kernel.perf_event_paranoid
sysctl, now that it became more paranoid (1 -> 2 [1]), this would need to be
updated, instead show the current value:

  [acme@jouet linux]$ perf record ls
  Error:
  You may not have permission to collect stats.

  Consider tweaking /proc/sys/kernel/perf_event_paranoid,
  which controls use of the performance events system by
  unprivileged users (without CAP_SYS_ADMIN).

  The current value is 2:

    -1: Allow use of (almost) all events by all users
  >= 0: Disallow raw tracepoint access by users without CAP_IOC_LOCK
  >= 1: Disallow CPU event access by users without CAP_SYS_ADMIN
  >= 2: Disallow kernel profiling by users without CAP_SYS_ADMIN
  [acme@jouet linux]$

[1] 0161028b ("perf/core: Change the default paranoia level to 2")
Reported-by: NIngo Molnar <mingo@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-0gc4rdpg8d025r5not8s8028@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      7d173913
  3. 12 5月, 2016 12 次提交
  5. 11 5月, 2016 9 次提交
  7. 10 5月, 2016 15 次提交
  9. 09 5月, 2016 1 次提交