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  1. 28 Sep, 2015 14 commits
  3. 25 Sep, 2015 3 commits
  5. 23 Sep, 2015 2 commits
    • Namhyung Kim's avatar
      perf record: Synthesize COMM event for a command line workload · e803cf97
      Namhyung Kim authored 
      
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: default avatarNamhyung Kim <namhyung@kernel.org>
Tested-by: default avatarArnaldo 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.org

Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
      e803cf97
    • Arnaldo Carvalho de Melo's avatar
      tools vm: Fix build due to removal of tools/lib/api/fs/debugfs.h · f6489bc2
      Arnaldo Carvalho de Melo authored 
      
There were some changes in how this debugfs mounting helper is
implemented/exported and we forgot to check if there were other users
besides perf, fix it.

Need to do a make -C tools/ everytime we do changes to
tools/{lib,include} and other places where we're moving things from
tools/perf/ to be used by other tools/ living code.

Fixed:

  $ make -C tools/vm
  make: Entering directory '/home/git/linux/tools/vm'
  make -C ../lib/api
  make[1]: Entering directory '/home/git/linux/tools/lib/api'
    CC       fd/array.o
    LD       fd/libapi-in.o
    CC       fs/fs.o
    CC       fs/tracing_path.o
    LD       fs/libapi-in.o
    CC       cpu.o
    LD       libapi-in.o
    AR       libapi.a
  make[1]: Leaving directory '/home/git/linux/tools/lib/api'
  gcc -Wall -Wextra -I../lib/ -o page-types page-types.c ../lib/api/libapi.a
  make: Leaving directory '/home/git/linux/tools/vm'
  $
Reported-by: default avatarVinson Lee <vlee@twopensource.com>
Tested-by: default avatarVinson Lee <vlee@twopensource.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Raphael Beamonte <raphael.beamonte@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: David Ahern <dsahern@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Namhyung Kim <namhyung@kernel.org>
Fixes: 60a1133a

 ("tools lib api fs: Remove debugfs, tracefs and findfs objects")
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
      f6489bc2
  7. 22 Sep, 2015 13 commits
  9. 21 Sep, 2015 2 commits
  11. 18 Sep, 2015 1 commit
    • Mark Rutland's avatar
      perf record: Avoid infinite loop at buildid processing with no samples · 381c02f6
      Mark Rutland authored 
      
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: default avatarMark Rutland <mark.rutland@arm.com>
Tested-by: default avatarArnaldo Carvalho de Melo <acme@kernel.org>
Tested-by: default avatarAdrian 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.com

Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
      381c02f6
  13. 17 Sep, 2015 5 commits
    • Peter Senna Tschudin's avatar
      perf tools: Bool functions shouldn't return -1 · bf644563
      Peter Senna Tschudin authored 
      
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: default avatarPeter 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.com

Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
      bf644563
    • Arnaldo Carvalho de Melo's avatar
      tools build: Add test for presence of __get_cpuid() gcc builtin · b0063dbf
      Arnaldo Carvalho de Melo authored 
      The auxtrace code needed by Intel PT uses the __get_cpuid() gcc builtin,
that is not present in old systems, breaking the build.

Add a test to check for that builtin and disable AUXTRACE in those
systems.

  [acme@rhel5 linux]$  make NO_LIBPERL=1 -C tools/perf O=/tmp/build/perf install-bin
  make: Entering directory `/home/acme/git/linux/tools/perf'
    BUILD:   Doing 'make -j2' parallel build

  Auto-detecting system features:
  <SNIP>
  ...                          lzma: [ on  ]
  ...                     get_cpuid: [ OFF ]
  <SNIP>
  config/Makefile:630: Your gcc lacks the __get_cpuid() builtin, disables support for auxtrace/Intel PT, please install a newer gcc
    MKDIR    /tmp/build/perf/util/
  <SNIP>

This fixes the build on old systems such as RHEL/CentOS 5.11.

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: Vinson Lee <vlee@twopensource.com>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-d4puslul0jltoodzpx9r4sje@git.kernel.org

Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
      b0063dbf
    • Arnaldo Carvalho de Melo's avatar
      tools build: Add test for presence of numa_num_possible_cpus() in libnuma · f8ac8606
      Arnaldo Carvalho de Melo authored 
      The existing numa test checks only if numa.h and numa_available() are
present, but that can be satisfied with an old libnuma that is not
enough for the 'perf bench numa' entry, so add a test to check for that:

  [acme@rhel5 linux]$  make NO_AUXTRACE=1 NO_LIBPERL=1 -C tools/perf O=/tmp/build/perf install-bin
  make: Entering directory `/home/acme/git/linux/tools/perf'
    BUILD:   Doing 'make -j2' parallel build

  Auto-detecting system features:
  ...                        libelf: [ on  ]
  ...                       libnuma: [ on  ]
  ...        numa_num_possible_cpus: [ OFF ]
  ...                       libperl: [ on  ]

  <SNIP>
  config/Makefile:577: Old numa library found, disables 'perf bench numa mem' benchmark, please install numactl-devel/libnuma-devel/libnuma-dev >= 2.0.8
    INSTALL  binaries
  <SNIP>

This fixes the build on old systems such as RHEL/CentOS 5.11.

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: Vinson Lee <vlee@twopensource.com>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-zqriqkezppi2de2iyjin1tnc@git.kernel.org

Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
      f8ac8606
    • Arnaldo Carvalho de Melo's avatar
      Revert "perf symbols: Fix mismatched declarations for elf_getphdrnum" · 179f36dd
      Arnaldo Carvalho de Melo authored 
      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: default avatarVinson 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.org

Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
      179f36dd
    • Heiko Carstens's avatar
      s390: wire up userfaultfd system call · 02243571
      Heiko Carstens authored 
      Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
      02243571

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