perf smt: Compute SMT from topology

The topology records sibling threads. Rather than computing SMT using
siblings in sysfs, reuse the values in topology. This only applies
when the file smt/active isn't available.

Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Ahmad Yasin <ahmad.yasin@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Caleb Biggers <caleb.biggers@intel.com>
Cc: Florian Fischer <florian.fischer@muhq.space>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.garry@huawei.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Kshipra Bopardikar <kshipra.bopardikar@intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Miaoqian Lin <linmq006@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Perry Taylor <perry.taylor@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Cc: Xing Zhengjun <zhengjun.xing@linux.intel.com>
Link: https://lore.kernel.org/r/20220831174926.579643-4-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 15 insertions, 0 deletions

diff --git a/tools/perf/util/cputopo.c b/tools/perf/util/cputopo.c
index d275d843c155..511002e52714 100644
--- a/tools/perf/util/cputopo.c
+++ b/tools/perf/util/cputopo.c
@@ -157,6 +157,21 @@ void cpu_topology__delete(struct cpu_topology *tp)
 	free(tp);
 }
 
+bool cpu_topology__smt_on(const struct cpu_topology *topology)
+{
+	for (u32 i = 0; i < topology->core_cpus_lists; i++) {
+		const char *cpu_list = topology->core_cpus_list[i];
+
+		/*
+		 * If there is a need to separate siblings in a core then SMT is
+		 * enabled.
+		 */
+		if (strchr(cpu_list, ',') || strchr(cpu_list, '-'))
+			return true;
+	}
+	return false;
+}
+
 static bool has_die_topology(void)
 {
 	char filename[MAXPATHLEN];