perf/core improvements and fixes:

User visible:

- perf trace --pf maj/min/all works with --call-graph: (Arnaldo Carvalho de Melo)

  Tracing write syscalls and major page faults with callchains while starting
  firefox, limiting the stack to 5 frames:

 # perf trace -e write --pf maj --max-stack 5 firefox
   589.549 ( 0.014 ms): firefox/15377 write(fd: 4, buf: 0x7fff80acc898, count: 151) = 151
                                       [0xfaed] (/usr/lib64/libpthread-2.22.so)
                                       fire_glxtest_process+0x5c (/usr/lib64/firefox/libxul.so)
                                       InstallGdkErrorHandler+0x41 (/usr/lib64/firefox/libxul.so)
                                       XREMain::XRE_mainInit+0x12c (/usr/lib64/firefox/libxul.so)
                                       XREMain::XRE_main+0x1e4 (/usr/lib64/firefox/libxul.so)
   760.704 ( 0.000 ms): firefox/15332 majfault [gtk_tree_view_accessible_get_type+0x0] => /usr/lib64/libgtk-3.so.0.1800.9@0xa0850 (x.)
                                       gtk_tree_view_accessible_get_type+0x0 (/usr/lib64/libgtk-3.so.0.1800.9)
                                       gtk_tree_view_class_intern_init+0x1a54 (/usr/lib64/libgtk-3.so.0.1800.9)
                                       g_type_class_ref+0x6dd (/usr/lib64/libgobject-2.0.so.0.4600.2)
                                       [0x115378] (/usr/lib64/libgnutls.so.30.6.3)

  This automagically selects "--call-graph dwarf", use "--call-graph fp" on systems
  where -fno-omit-frame-pointer was used to built the components of interest, to
  incur in less overhead, or tune "--call-graph dwarf" appropriately, see 'perf record --help'.

- Allow /proc/sys/kernel/perf_event_max_stack, that defaults to the old hard coded value
  of PERF_MAX_STACK_DEPTH (127), useful for huge callstacks for things like Groovy, Ruby, etc,
  and also to reduce overhead by limiting it to a smaller value, upcoming work will allow
  this to be done per-event (Arnaldo Carvalho de Melo)

- Make 'perf trace --min-stack' be honoured by --pf and --event (Arnaldo Carvalho de Melo)

- Make 'perf evlist -v' decode perf_event_attr->branch_sample_type (Arnaldo Carvalho de Melo)

   # perf record --call lbr usleep 1
   # perf evlist -v
   cycles:ppp: ... sample_type: IP|TID|TIME|CALLCHAIN|PERIOD|BRANCH_STACK, ...
            branch_sample_type: USER|CALL_STACK|NO_FLAGS|NO_CYCLES
   #

- Clear dummy entry accumulated period, fixing such 'perf top/report' output
  as: (Kan Liang)

    4769.98%  0.01%  0.00%  0.01%  tchain_edit  [kernel] [k] update_fast_timekeeper

- System calls with pid_t arguments gets them augmented with the COMM event
  more thoroughly:

  # trace -e perf_event_open perf stat -e cycles -p 15608
   6.876 ( 0.014 ms): perf_event_open(attr_uptr: 0x2ae20d8, pid: 15608 (hexchat), cpu: -1, group_fd: -1, flags: FD_CLOEXEC) = 3
   6.882 ( 0.005 ms): perf_event_open(attr_uptr: 0x2ae20d8, pid: 15639 (gmain), cpu: -1, group_fd: -1, flags: FD_CLOEXEC) = 4
   6.889 ( 0.005 ms): perf_event_open(attr_uptr: 0x2ae20d8, pid: 15640 (gdbus), cpu: -1, group_fd: -1, flags: FD_CLOEXEC) = 5
                                                            ^^^^^^^^^^^^^^^^^^
   ^C

- Fix offline module name mismatch issue in 'perf probe' (Ravi Bangoria)

- Fix module probe issue if no dwarf support in (Ravi Bangoria)

Assorted fixes:

- Fix off-by-one in write_buildid() (Andrey Ryabinin)

- Fix segfault when printing callchains in 'perf script' (Chris Phlipot)

- Replace assignment with comparison on assert check in 'perf test' entry (Colin Ian King)

- Fix off-by-one comparison in intel-pt code (Colin Ian King)

- Close target file on error path in 'perf probe' (Masami Hiramatsu)

- Set default kprobe group name if not given in 'perf probe' (Masami Hiramatsu)

- Avoid partial perf_event_header reads (Wang Nan)

Infrastructure:

- Update x86's syscall_64.tbl copy, adding preadv2 & pwritev2 (Arnaldo Carvalho de Melo)

- Make the x86 clean quiet wrt syscall table removal (Jiri Olsa)

Cleanups:

- Simplify wrapper for LOCK_PI in 'perf bench futex' (Davidlohr Bueso)

- Remove duplicate const qualifier (Eric Engestrom)

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2
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=MzXA
-----END PGP SIGNATURE-----