linux.git/tools/perf, branch v4.19-rc2

perf python: Fix pyrf_evlist__read_on_cpu() interface

2018-08-20T11:54:59+00:00

Jaroslav reported errors from valgrind over perf python script:

  # echo 0 > /sys/devices/system/cpu/cpu4/online
  # valgrind ./test.py
  ==7524== Memcheck, a memory error detector
  ...
  ==7524== Command: ./test.py
  ==7524==
  pid 7526 exited
  ==7524== Invalid read of size 8
  ==7524==    at 0xCC2C2B3: perf_mmap__read_forward (evlist.c:780)
  ==7524==    by 0xCC2A681: pyrf_evlist__read_on_cpu (python.c:959)
  ...
  ==7524==  Address 0x65c4868 is 16 bytes after a block of size 459,36..
  ==7524==    at 0x4C2B955: calloc (vg_replace_malloc.c:711)
  ==7524==    by 0xCC2F484: zalloc (util.h:35)
  ==7524==    by 0xCC2F484: perf_evlist__alloc_mmap (evlist.c:978)
  ...

The reason for this is in the python interface, that allows a script to
pass arbitrary cpu number, which is then used to access struct
perf_evlist::mmap array. That's obviously wrong and works only when if
all cpus are available and fails if some cpu is missing, like in the
example above.

This patch makes pyrf_evlist__read_on_cpu() search the evlist's maps
array for the proper map to access.

It's linear search at the moment. Based on the way how is the
read_on_cpu used, I don't think we need to be fast in here.  But we
could add some hash in the middle to make it fast/er.

We don't allow python interface to set write_backward event attribute,
so it's safe to check only evlist's mmaps.

Reported-by: Jaroslav Škarvada 
Signed-off-by: Jiri Olsa 
Cc: Alexander Shishkin 
Cc: David Ahern 
Cc: Joe Mario 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/20180817114556.28000-3-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf mmap: Store real cpu number in 'struct perf_mmap'

2018-08-20T11:54:59+00:00

Store the real cpu number in 'struct perf_mmap', which will be used by
python interface that allows user to read a particular memory map for
given cpu.

Signed-off-by: Jiri Olsa 
Cc: Alexander Shishkin 
Cc: David Ahern 
Cc: Jaroslav Škarvada 
Cc: Joe Mario 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/20180817114556.28000-2-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Remove ext from struct kmod_path

2018-08-20T11:54:59+00:00

Having comp carrying the compression ID, we no longer need return the
extension. Removing it and updating the automated test.

Signed-off-by: Jiri Olsa 
Cc: Alexander Shishkin 
Cc: David Ahern 
Cc: Michael Petlan 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/20180817094813.15086-14-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Add gzip_is_compressed function

2018-08-20T11:54:59+00:00

Add implementation of the is_compressed callback for gzip.

Signed-off-by: Jiri Olsa 
Cc: Alexander Shishkin 
Cc: David Ahern 
Cc: Michael Petlan 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/20180817094813.15086-13-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Add lzma_is_compressed function

2018-08-20T11:54:59+00:00

Add implementation of the is_compressed callback for lzma.

Signed-off-by: Jiri Olsa 
Cc: Alexander Shishkin 
Cc: David Ahern 
Cc: Michael Petlan 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/20180817094813.15086-12-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Add is_compressed callback to compressions array

2018-08-20T11:54:59+00:00

Add is_compressed callback to the compressions array, that returns 0 if
the file is compressed or != 0 if not.

The new callback is used to recognize the situation when we have a
'compressed' object, like:

  /lib/modules/.../drivers/net/ethernet/intel/igb/igb.ko.xz

but we need to read its debug data from debuginfo files, which might not
be compressed, like:

  /root/.debug/.build-id/d6/...c4b301f/debug

So even for a 'compressed' object we read debug data from a plain
uncompressed object. To keep this transparent, we detect this in
decompress_kmodule() and return the file descriptor to the uncompressed
file.

Signed-off-by: Jiri Olsa 
Cc: Alexander Shishkin 
Cc: David Ahern 
Cc: Michael Petlan 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/20180817094813.15086-11-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Move the temp file processing into decompress_kmodule

2018-08-20T11:54:59+00:00

We will add a compression check in the following patch and it makes it
easier if the file processing is done in a single place. It also makes
the current code simpler.

The decompress_kmodule function now returns the fd of the uncompressed
file and the file name in the pathname arg, if it's provided.

Signed-off-by: Jiri Olsa 
Cc: Alexander Shishkin 
Cc: David Ahern 
Cc: Michael Petlan 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/20180817094813.15086-10-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Use compression id in decompress_kmodule()

2018-08-20T11:54:59+00:00

Once we parsed out the compression ID, we dont need to iterate all
available compressions and we can call it directly.

Signed-off-by: Jiri Olsa 
Cc: Alexander Shishkin 
Cc: David Ahern 
Cc: Michael Petlan 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/20180817094813.15086-9-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Store compression id into struct dso

2018-08-20T11:54:59+00:00

Add comp to 'struct dso' to hold the compression index.  It will be used
in the following patches.

Signed-off-by: Jiri Olsa 
Cc: Alexander Shishkin 
Cc: David Ahern 
Cc: Michael Petlan 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/20180817094813.15086-8-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Add compression id into 'struct kmod_path'

2018-08-20T11:54:59+00:00

Store a decompression ID in 'struct kmod_path', so it can be later
stored in 'struct dso'.

Switch 'struct kmod_path's 'comp' from 'bool' to 'int' to return the
compressions array index. Add 0 index item into compressions array, so
that the comp usage stays as it was: 0 - no compression, != 0
compression index.

Update the kmod_path tests.

Committer notes:

Use a designated initializer + terminating comma, e.g. { .fmt = NULL, }, to fix
the build in several distros:

  centos:6:       util/dso.c:201: error: missing initializer
  centos:6:       util/dso.c:201: error: (near initialization for 'compressions[0].decompress')
  debian:9:       util/dso.c:201:24: error: missing field 'decompress' initializer [-Werror,-Wmissing-field-initializers]
  fedora:25:      util/dso.c:201:24: error: missing field 'decompress' initializer [-Werror,-Wmissing-field-initializers]
  fedora:26:      util/dso.c:201:24: error: missing field 'decompress' initializer [-Werror,-Wmissing-field-initializers]
  fedora:27:      util/dso.c:201:24: error: missing field 'decompress' initializer [-Werror,-Wmissing-field-initializers]
  oraclelinux:6:  util/dso.c:201: error: missing initializer
  oraclelinux:6:  util/dso.c:201: error: (near initialization for 'compressions[0].decompress')
  ubuntu:12.04.5: util/dso.c:201:2: error: missing initializer [-Werror=missing-field-initializers]
  ubuntu:12.04.5: util/dso.c:201:2: error: (near initialization for 'compressions[0].decompress') [-Werror=missing-field-initializers]
  ubuntu:16.04:   util/dso.c:201:24: error: missing field 'decompress' initializer [-Werror,-Wmissing-field-initializers]
  ubuntu:16.10:   util/dso.c:201:24: error: missing field 'decompress' initializer [-Werror,-Wmissing-field-initializers]
  ubuntu:16.10:   util/dso.c:201:24: error: missing field 'decompress' initializer [-Werror,-Wmissing-field-initializers]
  ubuntu:17.10:   util/dso.c:201:24: error: missing field 'decompress' initializer [-Werror,-Wmissing-field-initializers]

Signed-off-by: Jiri Olsa 
Cc: Alexander Shishkin 
Cc: David Ahern 
Cc: Michael Petlan 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/20180817094813.15086-7-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo