The -c or --combine-locks option is to merge lock instances in the
same class into a single entry.  It compares the name of the locks
and marks duplicated entries using lock_stat->combined.

 # perf lock report
                Name   acquired  contended   avg wait (ns) total wait (ns)   max wait (ns)   min wait (ns)

       rcu_read_lock     251225          0               0               0               0               0
 &(ei->i_block_re...       8731          0               0               0               0               0
 &sb->s_type->i_l...       8731          0               0               0               0               0
  hrtimer_bases.lock       5261          0               0               0               0               0
  hrtimer_bases.lock       2626          0               0               0               0               0
  hrtimer_bases.lock       1953          0               0               0               0               0
  hrtimer_bases.lock       1382          0               0               0               0               0
    cpu_hotplug_lock       1350          0               0               0               0               0
  hrtimer_bases.lock       1273          0               0               0               0               0
  hrtimer_bases.lock       1269          0               0               0               0               0

 # perf lock report -c
                Name   acquired  contended   avg wait (ns) total wait (ns)   max wait (ns)   min wait (ns)

       rcu_read_lock     251225          0               0               0               0               0
  hrtimer_bases.lock      39450          0               0               0               0               0
 &sb->s_type->i_l...      10301          1             662             662             662             662
    ptlock_ptr(page)      10173          2             701            1402             760             642
 &(ei->i_block_re...       8732          0               0               0               0               0
        &xa->xa_lock       8088          0               0               0               0               0
         &base->lock       6705          0               0               0               0               0
         &p->pi_lock       5549          0               0               0               0               0
 &dentry->d_lockr...       5010          4            1274            5097            1844             789
           &ep->lock       3958          0               0               0               0               0
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220127000050.3011493-6-namhyung@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>