linux.git/tools/perf/util, branch v5.5-rc2

perf affinity: Add infrastructure to save/restore affinity

2019-11-28T11:08:38+00:00

The kernel perf subsystem has to IPI to the target CPU for many
operations. On systems with many CPUs and when managing many events the
overhead can be dominated by lots of IPIs.

An alternative is to set up CPU affinity in the perf tool, then set up
all the events for that CPU, and then move on to the next CPU.

Add some affinity management infrastructure to enable such a model.
Used in followon patches.

Committer notes:

Use zfree() in some places, add missing stdbool.h header, some minor
coding style changes.

Signed-off-by: Andi Kleen 
Acked-by: Jiri Olsa 
Link: http://lore.kernel.org/lkml/20191121001522.180827-3-andi@firstfloor.org
Signed-off-by: Arnaldo Carvalho de Melo

perf pmu: Use file system cache to optimize sysfs access

2019-11-28T11:08:38+00:00

pmu.c does a lot of redundant /sys accesses while parsing aliases
and probing for PMUs. On large systems with a lot of PMUs this
can get expensive (>2s):

  % time     seconds  usecs/call     calls    errors syscall
  ------ ----------- ----------- --------- --------- ----------------
   27.25    1.227847           8    160888     16976 openat
   26.42    1.190481           7    164224    164077 stat

Add a cache to remember if specific file names exist or don't
exist, which eliminates most of this overhead.

Also optimize some stat() calls to be slightly cheaper access()

Resulting in:

    0.18    0.004166           2      1851       305 open
    0.08    0.001970           2       829       622 access

Signed-off-by: Andi Kleen 
Acked-by: Jiri Olsa 
Link: http://lore.kernel.org/lkml/20191121001522.180827-2-andi@firstfloor.org
Signed-off-by: Arnaldo Carvalho de Melo

perf regs: Make perf_reg_name() return "unknown" instead of NULL

2019-11-28T11:08:38+00:00

To avoid breaking the build on arches where this is not wired up, at
least all the other features should be made available and when using
this specific routine, the "unknown" should point the user/developer to
the need to wire this up on this particular hardware architecture.

Detected in a container mipsel debian cross build environment, where it
shows up as:

  In file included from /usr/mipsel-linux-gnu/include/stdio.h:867,
                   from /git/linux/tools/perf/lib/include/perf/cpumap.h:6,
                   from util/session.c:13:
  In function 'printf',
      inlined from 'regs_dump__printf' at util/session.c:1103:3,
      inlined from 'regs__printf' at util/session.c:1131:2:
  /usr/mipsel-linux-gnu/include/bits/stdio2.h:107:10: error: '%-5s' directive argument is null [-Werror=format-overflow=]
    107 |   return __printf_chk (__USE_FORTIFY_LEVEL - 1, __fmt, __va_arg_pack ());
        |          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

cross compiler details:

  mipsel-linux-gnu-gcc (Debian 9.2.1-8) 9.2.1 20190909

Also on mips64:

  In file included from /usr/mips64-linux-gnuabi64/include/stdio.h:867,
                   from /git/linux/tools/perf/lib/include/perf/cpumap.h:6,
                   from util/session.c:13:
  In function 'printf',
      inlined from 'regs_dump__printf' at util/session.c:1103:3,
      inlined from 'regs__printf' at util/session.c:1131:2,
      inlined from 'regs_user__printf' at util/session.c:1139:3,
      inlined from 'dump_sample' at util/session.c:1246:3,
      inlined from 'machines__deliver_event' at util/session.c:1421:3:
  /usr/mips64-linux-gnuabi64/include/bits/stdio2.h:107:10: error: '%-5s' directive argument is null [-Werror=format-overflow=]
    107 |   return __printf_chk (__USE_FORTIFY_LEVEL - 1, __fmt, __va_arg_pack ());
        |          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  In function 'printf',
      inlined from 'regs_dump__printf' at util/session.c:1103:3,
      inlined from 'regs__printf' at util/session.c:1131:2,
      inlined from 'regs_intr__printf' at util/session.c:1147:3,
      inlined from 'dump_sample' at util/session.c:1249:3,
      inlined from 'machines__deliver_event' at util/session.c:1421:3:
  /usr/mips64-linux-gnuabi64/include/bits/stdio2.h:107:10: error: '%-5s' directive argument is null [-Werror=format-overflow=]
    107 |   return __printf_chk (__USE_FORTIFY_LEVEL - 1, __fmt, __va_arg_pack ());
        |          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

cross compiler details:

  mips64-linux-gnuabi64-gcc (Debian 9.2.1-8) 9.2.1 20190909

Fixes: 2bcd355b71da ("perf tools: Add interface to arch registers sets")
Cc: Adrian Hunter 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Link: https://lkml.kernel.org/n/tip-95wjyv4o65nuaeweq31t7l1s@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf maps: Rename map_groups.h to maps.h

2019-11-26T14:07:46+00:00

One more step in the merge of 'struct maps' with 'struct map_groups'.

Cc: Adrian Hunter 
Cc: Andi Kleen 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Link: https://lkml.kernel.org/n/tip-9ibtn3vua76f934t7woyf26w@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf maps: Rename 'mg' variables to 'maps'

2019-11-26T14:07:46+00:00

Continuing the merge of 'struct maps' with 'struct map_groups'.

Cc: Adrian Hunter 
Cc: Andi Kleen 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Link: https://lkml.kernel.org/n/tip-z8d14wrw393a0fbvmnk1bqd9@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf map_symbol: Rename ms->mg to ms->maps

2019-11-26T14:07:46+00:00

One more step on the merge of 'struct maps' with 'struct map_groups'.

Cc: Adrian Hunter 
Cc: Andi Kleen 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Link: https://lkml.kernel.org/n/tip-61rra2wg392rhvdgw421wzpt@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf addr_location: Rename al->mg to al->maps

2019-11-26T14:07:46+00:00

One more step on the merge of 'struct maps' with 'struct map_groups'.

Cc: Adrian Hunter 
Cc: Andi Kleen 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Link: https://lkml.kernel.org/n/tip-foo95pyyp3bhocbt7yd8qrvq@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf thread: Rename thread->mg to thread->maps

2019-11-26T14:07:46+00:00

One more step on the merge of 'struct maps' with 'struct map_groups'.

Cc: Adrian Hunter 
Cc: Andi Kleen 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Link: https://lkml.kernel.org/n/tip-69vcr8pubpym90skxhmbwhiw@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf maps: Merge 'struct maps' with 'struct map_groups'

2019-11-26T14:07:46+00:00

And pick the shortest name: 'struct maps'.

The split existed because we used to have two groups of maps, one for
functions and one for variables, but that only complicated things,
sometimes we needed to figure out what was at some address and then had
to first try it on the functions group and if that failed, fall back to
the variables one.

That split is long gone, so for quite a while we had only one struct
maps per struct map_groups, simplify things by combining those structs.

First patch is the minimum needed to merge both, follow up patches will
rename 'thread->mg' to 'thread->maps', etc.

Cc: Adrian Hunter 
Cc: Andi Kleen 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Link: https://lkml.kernel.org/n/tip-hom6639ro7020o708trhxh59@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf map: Remove unused functions

2019-11-26T14:07:46+00:00

At some point those stopped being used, prune them.

Cc: Adrian Hunter 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Link: https://lkml.kernel.org/n/tip-p2k98mj3ff2uk1z95sbl5r6e@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo