perf evsel: Derive CPUs and threads in alloc_counts

Passing the number of CPUs and threads allows for an evsel's counts to
be mismatched to its cpu map. To avoid this always derive the counts
size from the cpu map. Change openat-syscall-all-cpus to set the cpus
to allow for this to work.
Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: John Garry <john.garry@huawei.com>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Clarke <pc@us.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Riccardo Mancini <rickyman7@gmail.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Suzuki Poulouse <suzuki.poulose@arm.com>
Cc: Vineet Singh <vineet.singh@intel.com>
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: zhengjun.xing@intel.com
Link: https://lore.kernel.org/r/20220105061351.120843-27-irogers@google.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/tests/openat-syscall-all-cpus.c

@@ -85,15 +85,7 @@ static int test__openat_syscall_event_on_all_cpus(struct test_suite *test __mayb
 		CPU_CLR(cpus->map[cpu], &cpu_set);
 	}
 
-	/*
-	 * Here we need to explicitly preallocate the counts, as if
-	 * we use the auto allocation it will allocate just for 1 cpu,
-	 * as we start by cpu 0.
-	 */
-	if (evsel__alloc_counts(evsel, cpus->nr, 1) < 0) {
-		pr_debug("evsel__alloc_counts(ncpus=%d)\n", cpus->nr);
-		goto out_close_fd;
-	}
+	evsel->core.cpus = perf_cpu_map__get(cpus);
 
 	err = 0;
 

tools/perf/util/counts.c

@@ -4,6 +4,7 @@
 #include <string.h>
 #include "evsel.h"
 #include "counts.h"
+#include <perf/threadmap.h>
 #include <linux/zalloc.h>
 
 struct perf_counts *perf_counts__new(int ncpus, int nthreads)
@@ -55,9 +56,12 @@ void evsel__reset_counts(struct evsel *evsel)
 	perf_counts__reset(evsel->counts);
 }
 
-int evsel__alloc_counts(struct evsel *evsel, int ncpus, int nthreads)
+int evsel__alloc_counts(struct evsel *evsel)
 {
-	evsel->counts = perf_counts__new(ncpus, nthreads);
+	struct perf_cpu_map *cpus = evsel__cpus(evsel);
+	int nthreads = perf_thread_map__nr(evsel->core.threads);
+
+	evsel->counts = perf_counts__new(cpus ? cpus->nr : 1, nthreads);
 	return evsel->counts != NULL ? 0 : -ENOMEM;
 }
 

tools/perf/util/counts.h

@@ -40,7 +40,7 @@ void perf_counts__delete(struct perf_counts *counts);
 void perf_counts__reset(struct perf_counts *counts);
 
 void evsel__reset_counts(struct evsel *evsel);
-int evsel__alloc_counts(struct evsel *evsel, int ncpus, int nthreads);
+int evsel__alloc_counts(struct evsel *evsel);
 void evsel__free_counts(struct evsel *evsel);
 
 #endif /* __PERF_COUNTS_H */

tools/perf/util/evsel.c

@@ -1578,7 +1578,7 @@ int __evsel__read_on_cpu(struct evsel *evsel, int cpu, int thread, bool scale)
 	if (FD(evsel, cpu, thread) < 0)
 		return -EINVAL;
 
-	if (evsel->counts == NULL && evsel__alloc_counts(evsel, cpu + 1, thread + 1) < 0)
+	if (evsel->counts == NULL && evsel__alloc_counts(evsel) < 0)
 		return -ENOMEM;
 
 	if (readn(FD(evsel, cpu, thread), &count, nv * sizeof(u64)) <= 0)

tools/perf/util/stat.c

@@ -152,11 +152,13 @@ static void evsel__free_stat_priv(struct evsel *evsel)
 	zfree(&evsel->stats);
 }
 
-static int evsel__alloc_prev_raw_counts(struct evsel *evsel, int ncpus, int nthreads)
+static int evsel__alloc_prev_raw_counts(struct evsel *evsel)
 {
+	int cpu_map_nr = evsel__nr_cpus(evsel);
+	int nthreads = perf_thread_map__nr(evsel->core.threads);
 	struct perf_counts *counts;
 
-	counts = perf_counts__new(ncpus, nthreads);
+	counts = perf_counts__new(cpu_map_nr, nthreads);
 	if (counts)
 		evsel->prev_raw_counts = counts;
 
@@ -177,12 +179,9 @@ static void evsel__reset_prev_raw_counts(struct evsel *evsel)
 
 static int evsel__alloc_stats(struct evsel *evsel, bool alloc_raw)
 {
-	int ncpus = evsel__nr_cpus(evsel);
-	int nthreads = perf_thread_map__nr(evsel->core.threads);
-
 	if (evsel__alloc_stat_priv(evsel) < 0 ||
-	    evsel__alloc_counts(evsel, ncpus, nthreads) < 0 ||
-	    (alloc_raw && evsel__alloc_prev_raw_counts(evsel, ncpus, nthreads) < 0))
+	    evsel__alloc_counts(evsel) < 0 ||
+	    (alloc_raw && evsel__alloc_prev_raw_counts(evsel) < 0))
 		return -ENOMEM;
 
 	return 0;