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libperf cpumap: Use binary search in perf_cpu_map__idx() as array are sorted

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Since 7074674e73 ("perf cpumap: Maintain cpumaps ordered and
without dups") perf_cpu_map elements are sorted in ascending order.

This patch improves perf_cpu_map__idx() by using a binary search.

Signed-off-by: Riccardo Mancini <rickyman7@gmail.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@redhat.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/f1543c15797169c21e8b205a4a6751159180580d.1629490974.git.rickyman7@gmail.com
[ Removed 'else' after if + return, declared variables where needed ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Riccardo Mancini 2021-08-21 11:19:07 +02:00 committed by Arnaldo Carvalho de Melo
parent 47e7dd34a2
commit 73e40c9bd4
1 changed files with 12 additions and 4 deletions
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16
tools/lib/perf/cpumap.c
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@ -270,11 +270,19 @@ bool perf_cpu_map__empty(const struct perf_cpu_map *map)
int perf_cpu_map__idx(struct perf_cpu_map *cpus, int cpu)
{
int i;
int low = 0, high = cpus->nr;
for (i = 0; i < cpus->nr; ++i) {
if (cpus->map[i] == cpu)
return i;
while (low < high) {
int idx = (low + high) / 2,
cpu_at_idx = cpus->map[idx];
if (cpu_at_idx == cpu)
return idx;
if (cpu_at_idx > cpu)
high = idx;
else
low = idx + 1;
}
return -1;