Commit Graph

4 Commits

Author SHA1 Message Date
Ian Rogers
046fd8206d perf tools: Make more global variables static
`make check` will run sparse on the perf code base. A frequent warning
is "warning: symbol '...' was not declared. Should it be static?" Go
through and make global definitions without declarations static.

In some cases it is deliberate due to dlsym accessing the symbol, this
change doesn't clean up the missing declarations for perf test suites.

Sometimes things can opportunistically be made const.

Making somethings static exposed unused functions warnings, so
restructuring of ifdefs was necessary for that.

These changes reduce the size of the perf binary by 568 bytes.

Committer notes:

Refreshed the patch, the original one fell thru the cracks, updated the
size reduction.

Remove the trace-event-scripting.c changes, break the build, noticed
with container builds and with sashiko:

  https://sashiko.dev/#/patchset/20260401215306.2152898-1-acme%40kernel.org

Also make two variables static to address another sashiko review
comment:

  https://sashiko.dev/#/patchset/20260402001740.2220481-1-acme%40kernel.org

Signed-off-by: Ian Rogers <irogers@google.com>
Acked-by: Ankur Arora <ankur.a.arora@oracle.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Cc: Guo Ren <guoren@kernel.org>
Cc: Howard Chu <howardchu95@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Leo Yan <leo.yan@arm.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <pjw@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Yujie Liu <yujie.liu@intel.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
2026-04-08 19:21:04 -07:00
Kajol Jain
9823ae6f68 perf bench breakpoint: Skip run if no breakpoints available
Based on commit 7d54a4acd8 ("perf test: Skip watchpoint tests if
no watchpoints available"), hardware breakpoints are not available for
power9 platform and because of that 'perf bench breakpoint' run fails on
power9 platform.

Add code to check for the return value of perf_event_open() in the
breakpoint run and skip the 'perf bench breakpoint' run, if hardware
breakpoints are not available.

Result on power9 system before patch changes:

  [command]# perf bench breakpoint thread
  perf_event_open: No such device

Result on power9 system after patch changes:

  [command]# ./perf bench breakpoint thread
  Skipping perf bench breakpoint thread: No hardware support

Reported-by: Disha Goel <disgoel@linux.vnet.ibm.com>
Signed-off-by: Kajol Jain <kjain@linux.ibm.com>
Acked-by: Naveen N Rao <naveen@kernel.org>
Cc: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Cc: Disha Goel <disgoel@linux.ibm.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: linuxppc-dev@lists.ozlabs.org
Link: https://lore.kernel.org/r/20230823075103.190565-1-kjain@linux.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2023-08-23 08:39:02 -03:00
Arnaldo Carvalho de Melo
df36d2572e perf bench breakpoint: Fix build on 32-bit arches
Cast pointers to unsigned long instead of to uint64_t to avoid this
problem on 32-bit arches:

  31     6.89 debian:experimental-x-mips    : FAIL gcc version 11.2.0 (Debian 11.2.0-18)
    bench/breakpoint.c: In function 'breakpoint_setup':
    bench/breakpoint.c:56:24: error: cast from pointer to integer of different size [-Werror=pointer-to-int-cast]
       56 |         attr.bp_addr = (uint64_t)addr;
          |                        ^
    cc1: all warnings being treated as errors
    make[3]: *** [/git/perf-5.18.0-rc7/tools/build/Makefile.build:139: bench] Error 2

Fixes: 68a6772f11 ("perf bench: Add breakpoint benchmarks")
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Marco Elver <elver@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/YoLq1nHx1doi+VWl@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2022-05-16 21:23:09 -03:00
Dmitry Vyukov
68a6772f11 perf bench: Add breakpoint benchmarks
Add 2 benchmarks:

1. Performance of thread creation/exiting in presence of breakpoints.
2. Performance of breakpoint modification in presence of threads.

The benchmarks capture use cases that we are interested in:
using inheritable breakpoints in large highly-threaded applications.

The benchmarks show significant slowdown imposed by breakpoints
(even when they don't fire).

Testing on Intel 8173M with 112 HW threads show:

  perf bench --repeat=56 breakpoint thread --breakpoints=0 --parallelism=56 --threads=20
        78.675000 usecs/op
  perf bench --repeat=56 breakpoint thread --breakpoints=4 --parallelism=56 --threads=20
     12967.135714 usecs/op

That's 165x slowdown due to presence of the breakpoints.

  perf bench --repeat=20000 breakpoint enable --passive=0 --active=0
         1.433250 usecs/op
  perf bench --repeat=20000 breakpoint enable --passive=224 --active=0
       585.318400 usecs/op
  perf bench --repeat=20000 breakpoint enable --passive=0 --active=111
       635.953000 usecs/op

That's 408x and 444x slowdown due to presence of threads.

Profiles show some overhead in toggle_bp_slot,
but also very high contention:

    90.83%  breakpoint-thre  [kernel.kallsyms]  [k] osq_lock
     4.69%  breakpoint-thre  [kernel.kallsyms]  [k] mutex_spin_on_owner
     2.06%  breakpoint-thre  [kernel.kallsyms]  [k] __reserve_bp_slot
     2.04%  breakpoint-thre  [kernel.kallsyms]  [k] toggle_bp_slot

    79.01%  breakpoint-enab  [kernel.kallsyms]  [k] smp_call_function_single
     9.94%  breakpoint-enab  [kernel.kallsyms]  [k] llist_add_batch
     5.70%  breakpoint-enab  [kernel.kallsyms]  [k] _raw_spin_lock_irq
     1.84%  breakpoint-enab  [kernel.kallsyms]  [k] event_function_call
     1.12%  breakpoint-enab  [kernel.kallsyms]  [k] send_call_function_single_ipi
     0.37%  breakpoint-enab  [kernel.kallsyms]  [k] generic_exec_single
     0.24%  breakpoint-enab  [kernel.kallsyms]  [k] __perf_event_disable
     0.20%  breakpoint-enab  [kernel.kallsyms]  [k] _perf_event_enable
     0.18%  breakpoint-enab  [kernel.kallsyms]  [k] toggle_bp_slot

Committer notes:

Fixup struct init for older compilers:

   3    32.90 alpine:3.5                    : FAIL clang version 3.8.1 (tags/RELEASE_381/final)
    bench/breakpoint.c:49:34: error: missing field 'size' initializer [-Werror,-Wmissing-field-initializers]
            struct perf_event_attr attr = {0};
                                            ^
    1 error generated.
   7    37.31 alpine:3.9                    : FAIL gcc version 8.3.0 (Alpine 8.3.0)
    bench/breakpoint.c:49:34: error: missing field 'size' initializer [-Werror,-Wmissing-field-initializers]
            struct perf_event_attr attr = {0};
                                            ^
    1 error generated.

Signed-off-by: Dmitriy Vyukov <dvyukov@google.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Ian Rogers <irogers@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Marco Elver <elver@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220505155745.1690906-1-dvyukov@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2022-05-13 11:00:38 -03:00