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Date: Mon, 28 Mar 2022 17:59:02 -0300 From: Arnaldo Carvalho de Melo <arnaldo.melo@...il.com> To: Ian Rogers <irogers@...gle.com>, Arnaldo Carvalho de Melo <acme@...nel.org> CC: Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>, Mark Rutland <mark.rutland@....com>, Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Jiri Olsa <jolsa@...nel.org>, Namhyung Kim <namhyung@...nel.org>, Mathieu Poirier <mathieu.poirier@...aro.org>, Suzuki K Poulose <suzuki.poulose@....com>, Mike Leach <mike.leach@...aro.org>, Leo Yan <leo.yan@...aro.org>, John Garry <john.garry@...wei.com>, Will Deacon <will@...nel.org>, Alexei Starovoitov <ast@...nel.org>, Daniel Borkmann <daniel@...earbox.net>, Andrii Nakryiko <andrii@...nel.org>, Martin KaFai Lau <kafai@...com>, Song Liu <songliubraving@...com>, Yonghong Song <yhs@...com>, John Fastabend <john.fastabend@...il.com>, KP Singh <kpsingh@...nel.org>, Kajol Jain <kjain@...ux.ibm.com>, James Clark <james.clark@....com>, German Gomez <german.gomez@....com>, Adrian Hunter <adrian.hunter@...el.com>, Riccardo Mancini <rickyman7@...il.com>, Andi Kleen <ak@...ux.intel.com>, Alexey Bayduraev <alexey.v.bayduraev@...ux.intel.com>, Alexander Antonov <alexander.antonov@...ux.intel.com>, linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org, coresight@...ts.linaro.org, linux-arm-kernel@...ts.infradead.org, netdev@...r.kernel.org, bpf@...r.kernel.org, Stephane Eranian <eranian@...gle.com> Subject: Re: [PATCH 3/5] perf cpumap: Add intersect function. On March 28, 2022 5:54:06 PM GMT-03:00, Ian Rogers <irogers@...gle.com> wrote: >On Mon, Mar 28, 2022 at 1:28 PM Arnaldo Carvalho de Melo ><acme@...nel.org> wrote: >> >> Em Sun, Mar 27, 2022 at 11:24:12PM -0700, Ian Rogers escreveu: >> > The merge function gives the union of two cpu maps. Add an intersect >> > function which will be used in the next change. >> > >> > Signed-off-by: Ian Rogers <irogers@...gle.com> >> > --- >> > tools/lib/perf/cpumap.c | 38 ++++++++++++++++++++++++++++ >> > tools/lib/perf/include/perf/cpumap.h | 2 ++ >> > 2 files changed, 40 insertions(+) >> > >> > diff --git a/tools/lib/perf/cpumap.c b/tools/lib/perf/cpumap.c >> > index 953bc50b0e41..56b4d213039f 100644 >> > --- a/tools/lib/perf/cpumap.c >> > +++ b/tools/lib/perf/cpumap.c >> > @@ -393,3 +393,41 @@ struct perf_cpu_map *perf_cpu_map__merge(struct perf_cpu_map *orig, >> > perf_cpu_map__put(orig); >> > return merged; >> > } >> > + >> > +struct perf_cpu_map *perf_cpu_map__intersect(struct perf_cpu_map *orig, >> > + struct perf_cpu_map *other) >> > +{ >> > + struct perf_cpu *tmp_cpus; >> > + int tmp_len; >> > + int i, j, k; >> > + struct perf_cpu_map *merged = NULL; >> > + >> > + if (perf_cpu_map__is_subset(other, orig)) >> > + return orig; >> > + if (perf_cpu_map__is_subset(orig, other)) { >> > + perf_cpu_map__put(orig); >> >> Why this put(orig)? > >As with merge, if orig isn't returned then it is put. For merge I can see it dropping a reference, i.e. get b and merge it into a, after that b was "consumed" But for intersect? > >> > + return perf_cpu_map__get(other); >> >> And why the get here and not on the first if? > >The first argument orig is either put or returned while the second may >be returned only if the reference count is incremented. We could >change the API for merge and intersect to put both arguments, or to >not put either argument. > >Thanks, >Ian > >> > + } >> > + >> > + tmp_len = max(orig->nr, other->nr); >> > + tmp_cpus = malloc(tmp_len * sizeof(struct perf_cpu)); >> > + if (!tmp_cpus) >> > + return NULL; >> > + >> > + i = j = k = 0; >> > + while (i < orig->nr && j < other->nr) { >> > + if (orig->map[i].cpu < other->map[j].cpu) >> > + i++; >> > + else if (orig->map[i].cpu > other->map[j].cpu) >> > + j++; >> > + else { >> > + j++; >> > + tmp_cpus[k++] = orig->map[i++]; >> > + } >> > + } >> > + if (k) >> > + merged = cpu_map__trim_new(k, tmp_cpus); >> > + free(tmp_cpus); >> > + perf_cpu_map__put(orig); >> > + return merged; >> > +} >> > diff --git a/tools/lib/perf/include/perf/cpumap.h b/tools/lib/perf/include/perf/cpumap.h >> > index 4a2edbdb5e2b..a2a7216c0b78 100644 >> > --- a/tools/lib/perf/include/perf/cpumap.h >> > +++ b/tools/lib/perf/include/perf/cpumap.h >> > @@ -19,6 +19,8 @@ LIBPERF_API struct perf_cpu_map *perf_cpu_map__read(FILE *file); >> > LIBPERF_API struct perf_cpu_map *perf_cpu_map__get(struct perf_cpu_map *map); >> > LIBPERF_API struct perf_cpu_map *perf_cpu_map__merge(struct perf_cpu_map *orig, >> > struct perf_cpu_map *other); >> > +LIBPERF_API struct perf_cpu_map *perf_cpu_map__intersect(struct perf_cpu_map *orig, >> > + struct perf_cpu_map *other); >> > LIBPERF_API void perf_cpu_map__put(struct perf_cpu_map *map); >> > LIBPERF_API struct perf_cpu perf_cpu_map__cpu(const struct perf_cpu_map *cpus, int idx); >> > LIBPERF_API int perf_cpu_map__nr(const struct perf_cpu_map *cpus); >> > -- >> > 2.35.1.1021.g381101b075-goog >> >> -- >> >> - Arnaldo
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