summary refs log tree commit diff
path: root/tools/build/feature
diff options
context:
space:
mode:
authorArnaldo Carvalho de Melo <acme@redhat.com>2020-05-28 17:21:29 -0300
committerArnaldo Carvalho de Melo <acme@redhat.com>2020-05-29 16:51:11 -0300
commitd21cb73a9025ffa9ef4f5a0d4051780c264fa02e (patch)
treeefcae80ab733a9e9bb64518f33b2b0be262ecfc8 /tools/build/feature
parenta9e8c1f85696057e35fc316af3ae7aa00ddb7522 (diff)
downloadlinux-d21cb73a9025ffa9ef4f5a0d4051780c264fa02e.tar.gz
perf trace: Grow the syscall table as needed when using libaudit
The audit-libs API doesn't provide a way to figure out what is the
syscall with the greatest number/id, take that into account when using
that method to go on growing the syscall table as we the syscalls go on
appearing on the radar.

With this the libaudit based method is back working, i.e. when building
with:

  $ make NO_SYSCALL_TABLE=1 O=/tmp/build/perf -C tools/perf install-bin
  <SNIP>
  Auto-detecting system features:
  <SNIP>
  ...                      libaudit: [ on  ]
  ...                        libbfd: [ on  ]
  ...                        libcap: [ on  ]
  <SNIP>
  $ ldd ~/bin/perf | grep audit
	libaudit.so.1 => /lib64/libaudit.so.1 (0x00007faef22df000)
  $

perf trace is back working, which makes it functional in arches other
than x86_64, powerpc, arm64 and s390, that provides these generators:

  $ find tools/perf/arch/ -name "*syscalltbl*"
  tools/perf/arch/x86/entry/syscalls/syscalltbl.sh
  tools/perf/arch/arm64/entry/syscalls/mksyscalltbl
  tools/perf/arch/s390/entry/syscalls/mksyscalltbl
  tools/perf/arch/powerpc/entry/syscalls/mksyscalltbl
  $

Example output forcing the libaudit method on x86_64:

  # perf trace -e file,nanosleep sleep 0.001
           ? (         ): sleep/859090  ... [continued]: execve())                                   = 0
       0.045 ( 0.005 ms): sleep/859090 access(filename: 0x8733e850, mode: R)                         = -1 ENOENT (No such file or directory)
       0.055 ( 0.005 ms): sleep/859090 openat(dfd: CWD, filename: 0x8733ba29, flags: RDONLY|CLOEXEC) = 3
       0.079 ( 0.005 ms): sleep/859090 openat(dfd: CWD, filename: 0x87345d20, flags: RDONLY|CLOEXEC) = 3
       0.085 ( 0.002 ms): sleep/859090 read(fd: 3, buf: 0x7ffd9d483f58, count: 832)                  = 832
       0.090 ( 0.002 ms): sleep/859090 read(fd: 3, buf: 0x7ffd9d483b50, count: 784)                  = 784
       0.094 ( 0.002 ms): sleep/859090 read(fd: 3, buf: 0x7ffd9d483b20, count: 32)                   = 32
       0.098 ( 0.002 ms): sleep/859090 read(fd: 3, buf: 0x7ffd9d483ad0, count: 68)                   = 68
       0.109 ( 0.002 ms): sleep/859090 read(fd: 3, buf: 0x7ffd9d483a50, count: 784)                  = 784
       0.113 ( 0.002 ms): sleep/859090 read(fd: 3, buf: 0x7ffd9d483730, count: 32)                   = 32
       0.117 ( 0.002 ms): sleep/859090 read(fd: 3, buf: 0x7ffd9d483710, count: 68)                   = 68
       0.320 ( 0.008 ms): sleep/859090 openat(dfd: CWD, filename: 0x872c3660, flags: RDONLY|CLOEXEC) = 3
       0.372 ( 1.057 ms): sleep/859090 nanosleep(rqtp: 0x7ffd9d484ac0)                               = 0
  #

There are still some limitations when using the libaudit method, that
will be fixed at some point, i.e., this works with the mksyscalltbl
method but not with libaudit's:

  # perf trace -e file,*sleep sleep 0.001
  event syntax error: '*sleep'
                       \___ parser error
  Run 'perf list' for a list of valid events

   Usage: perf trace [<options>] [<command>]
      or: perf trace [<options>] -- <command> [<options>]
      or: perf trace record [<options>] [<command>]
      or: perf trace record [<options>] -- <command> [<options>]

      -e, --event <event>   event/syscall selector. use 'perf list' to list available events
  #

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/build/feature')
0 files changed, 0 insertions, 0 deletions