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  1. 01 10月, 2015 13 次提交
  3. 29 9月, 2015 18 次提交
  5. 25 9月, 2015 2 次提交
    • A
      perf tools: Fix copying of /proc/kcore · b5cabbcb
      由 Adrian Hunter 提交于 
      A copy of /proc/kcore containing the kernel text can be made to the
buildid cache. e.g.

	perf buildid-cache -v -k /proc/kcore

To workaround objdump limitations, a copy is also made when annotating
against /proc/kcore.

The copying process stops working from libelf about v1.62 onwards (the
problem was found with v1.63).

The cause is that a call to gelf_getphdr() in kcore__add_phdr() fails
because additional validation has been added to gelf_getphdr().

The use of gelf_getphdr() is a misguided attempt to get default
initialization of the Gelf_Phdr structure.  That should not be
necessary because every member of the Gelf_Phdr structure is
subsequently assigned.  So just remove the call to gelf_getphdr().

Similarly, a call to gelf_getehdr() in gelf_kcore__init() can be
removed also.

Committer notes:

Note to stable@kernel.org, from Adrian in the cover letter for this
patchkit:

The "Fix copying of /proc/kcore" problem goes back to v3.13 if you think
it is important enough for stable.
Signed-off-by: NAdrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: stable@kernel.org
Link: http://lkml.kernel.org/r/1443089122-19082-3-git-send-email-adrian.hunter@intel.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      b5cabbcb
    • A
      perf probe: Use existing routine to look for a kernel module by dso->short_name · 266fa2b2
      由 Arnaldo Carvalho de Melo 提交于 
      We have map_groups__find_by_name() to look at the list of modules that
are in place for a given machine, so use it instead of traversing the
machine dso list, which also includes DSOs for userspace.

When merging the user and kernel DSO lists a bug was introduced where
'perf probe' stopped being able to add probes to modules using its short
name:

  # perf probe -m usbnet --add usbnet_start_xmit
  usbnet_start_xmit is out of .text, skip it.
    Error: Failed to add events.
  #

With this fix it works again:

  # perf probe -m usbnet --add usbnet_start_xmit
  Added new event:
    probe:usbnet_start_xmit (on usbnet_start_xmit in usbnet)

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

  	perf record -e probe:usbnet_start_xmit -aR sleep 1
  #
Reported-by: NWang Nan <wangnan0@huawei.com>
Acked-by: NMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Fixes: 3d39ac53 ("perf machine: No need to have two DSOs lists")
Link: http://lkml.kernel.org/r/20150924015008.GE1897@kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      266fa2b2
  7. 23 9月, 2015 1 次提交
    • N
      perf record: Synthesize COMM event for a command line workload · e803cf97
      由 Namhyung Kim 提交于 
      When perf creates a new child to profile, the events are enabled on
exec().  And in this case, it doesn't synthesize any event for the
child since they'll be generated during exec().  But there's an window
between the enabling and the event generation.

It used to be overcome since samples are only in kernel (so we always
have the map) and the comm is overridden by a later COMM event.
However it won't work if events are processed and displayed before the
COMM event overrides like in 'perf script'.  This leads to those early
samples (like native_write_msr_safe) not having a comm but pid (like
':15328').

So it needs to synthesize COMM event for the child explicitly before
enabling so that it can have a correct comm.  But at this time, the
comm will be "perf" since it's not exec-ed yet.

Committer note:

Before this patch:

  # perf record usleep 1
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.017 MB perf.data (7 samples) ]
  # perf script --show-task-events
    :4429  4429 27909.079372:          1 cycles:  ffffffff8105f45a native_write_msr_safe (/lib/modules/4.
    :4429  4429 27909.079375:          1 cycles:  ffffffff8105f45a native_write_msr_safe (/lib/modules/4.
    :4429  4429 27909.079376:         10 cycles:  ffffffff8105f45a native_write_msr_safe (/lib/modules/4.
    :4429  4429 27909.079377:        223 cycles:  ffffffff8105f45a native_write_msr_safe (/lib/modules/4.
    :4429  4429 27909.079378:       6571 cycles:  ffffffff8105f45a native_write_msr_safe (/lib/modules/4.
   usleep  4429 27909.079380: PERF_RECORD_COMM exec: usleep:4429/4429
   usleep  4429 27909.079381:     185403 cycles:  ffffffff810a72d3 flush_signal_handlers (/lib/modules/4.
   usleep  4429 27909.079444:    2241110 cycles:      7fc575355be3 _dl_start (/usr/lib64/ld-2.20.so)
   usleep  4429 27909.079875: PERF_RECORD_EXIT(4429:4429):(4429:4429)

After:

  # perf record usleep 1
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.017 MB perf.data (7 samples) ]
  # perf script --show-task
     perf     0     0.000000: PERF_RECORD_COMM: perf:8446/8446
     perf  8446 30154.038944:          1 cycles:  ffffffff8105f45a native_write_msr_safe (/lib/modules/4.
     perf  8446 30154.038948:          1 cycles:  ffffffff8105f45a native_write_msr_safe (/lib/modules/4.
     perf  8446 30154.038949:          9 cycles:  ffffffff8105f45a native_write_msr_safe (/lib/modules/4.
     perf  8446 30154.038950:        230 cycles:  ffffffff8105f45a native_write_msr_safe (/lib/modules/4.
     perf  8446 30154.038951:       6772 cycles:  ffffffff8105f45a native_write_msr_safe (/lib/modules/4.
   usleep  8446 30154.038952: PERF_RECORD_COMM exec: usleep:8446/8446
   usleep  8446 30154.038954:     196923 cycles:  ffffffff81766440 _raw_spin_lock (/lib/modules/4.3.0-rc1
   usleep  8446 30154.039021:    2292130 cycles:      7f609a173dc4 memcpy (/usr/lib64/ld-2.20.so)
   usleep  8446 30154.039349: PERF_RECORD_EXIT(8446:8446):(8446:8446)
  #
Signed-off-by: NNamhyung Kim <namhyung@kernel.org>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1442881495-2928-1-git-send-email-namhyung@kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      e803cf97
  9. 22 9月, 2015 1 次提交
  11. 18 9月, 2015 3 次提交
    • M
      perf record: Avoid infinite loop at buildid processing with no samples · 381c02f6
      由 Mark Rutland 提交于 
      If a session contains no events, we can get stuck in an infinite loop in
__perf_session__process_events, with a non-zero file_size and data_offset, but
a zero data_size.

In this case, we can mmap the entirety of the file (consisting of the file and
attribute headers), and fetch_mmaped_event will correctly refuse to read any
(unmapped and non-existent) event headers. This causes
__perf_session__process_events to unmap the file and retry with the exact same
parameters, getting stuck in an infinite loop.

This has been observed to result in an exit-time hang when counting
rare/unschedulable events with perf record, and can be triggered artificially
with the script below:

  ----
  #!/bin/sh
  printf "REPRO: launching perf\n";
  ./perf record -e software/config=9/ sleep 1 &
  PERF_PID=$!;
  sleep 0.002;
  kill -2 $PERF_PID;
  printf "REPRO: waiting for perf (%d) to exit...\n" "$PERF_PID";
  wait $PERF_PID;
  printf "REPRO: perf exited\n";
  ----

To avoid this, have __perf_session__process_events bail out early when
the file has no data (i.e. it has no events).

Commiter note:

I only managed to reproduce this when setting
/proc/sys/kernel/kptr_restrict to '1' and changing the code to
purposefully not process any samples and no synthesized samples, i.e.
kptr_restrict prevents 'record' from synthesizing the kernel mmaps for
vmlinux + modules and since it is a workload started from perf, we don't
synthesize mmap/comm records for existing threads.

Adrian Hunter managed to reproduce it in his environment tho.
Signed-off-by: NMark Rutland <mark.rutland@arm.com>
Tested-by: NArnaldo Carvalho de Melo <acme@kernel.org>
Tested-by: NAdrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1442423929-12253-1-git-send-email-mark.rutland@arm.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      381c02f6
    • P
      perf tools: Bool functions shouldn't return -1 · bf644563
      由 Peter Senna Tschudin 提交于 
      Returning a negative value for a boolean function seem to have the
undesired effect of returning true. Replace -1 by false in a
bool-returning function.

The diff of the .s file before and after the change (for x86_64):

  3907c3907
  < 	movl	$1, %ebx
  ---
  > 	xorl	%ebx, %ebx

while if -1 is replaced by true, the diff is empty.

This issue was found by the following Coccinelle semantic patch:

  <smpl>
  @@
  identifier f;
  constant C;
  typedef bool;
  @@
  bool f (...){
  <+...
  * return -C;
  ...+>
  }
  </smpl>
Signed-off-by: NPeter Senna Tschudin <peter.senna@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Matt Fleming <matt.fleming@intel.com>
Cc: Milos Vyletel <milos@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/1442484533-19742-1-git-send-email-peter.senna@gmail.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      bf644563
    • A
      Revert "perf symbols: Fix mismatched declarations for elf_getphdrnum" · 179f36dd
      由 Arnaldo Carvalho de Melo 提交于 
      This reverts commit f785f235.

We have a test to check if elf_getphdrnum() is present, so, if it fails,
we'll get:

  [acme@rhel5 linux]$ cat /tmp/build/perf/feature/test-libelf-getphdrnum.make.output
  cc1: warnings being treated as errors
  test-libelf-getphdrnum.c: In function ‘main’:
  test-libelf-getphdrnum.c:7: warning: implicit declaration of function ‘elf_getphdrnum’
  [acme@rhel5 linux]$

And this block will not be compiled:

  #ifndef HAVE_ELF_GETPHDRNUM_SUPPORT
  static int elf_getphdrnum(Elf *elf, size_t *dst)
  ...
  #endif

So, if elf_getphdrnum() is being defined somewhere, there is a problem
with the test that is not detecting that function, go fix it.
Reported-by: NVinson Lee <vlee@twopensource.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Victor Kamensky <victor.kamensky@linaro.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-qn459fal6acvcvm50i8zxx9k@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      179f36dd
  13. 17 9月, 2015 1 次提交
    • S
      perf stat: Fix per-pkg event reporting bug · 02d8dabc
      由 Stephane Eranian 提交于 
      Per-pkg events need to be captured once per processor socket. The code
in check_per_pkg() ensures only one value per processor package is used.
However there is a problem with this function in case the first CPU of
the package does not measure anything for the per-pkg event, but other
CPUs do.

Consider the following:

  $ create cgroup FOO; echo $$ >FOO/tasks; taskset -c 1 noploop &
  $ perf stat -a -I 1000 -e intel_cqm/llc_occupancy/ -G FOO sleep 100
    1.00000 <not counted> Bytes intel_cqm/llc_occupancy/  FOO

The reason for this is that CPU0 in the cgroup has nothing running on it.
Yet check_per_plg() will mark socket0 as processed and no other event
value will be considered for the socket.

This patch fixes the problem by having check_per_pkg() only consider
events which actually ran.
Signed-off-by: NStephane Eranian <eranian@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1441286620-10117-1-git-send-email-eranian@google.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      02d8dabc
  15. 15 9月, 2015 1 次提交