Thread (8 messages) 8 messages, 3 authors, 2021-11-25
STALE1650d LANDED

[PATCH v2 4/4] perf tools: Probe non-deprecated sysfs path 1st

From: Ian Rogers <irogers@google.com>
Date: 2021-11-24 00:12:50
Also in: lkml
Subsystem: performance events subsystem, the rest · Maintainers: Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo, Namhyung Kim, Linus Torvalds

Following Documentation/ABI/stable/sysfs-devices-system-cpu the
/sys/devices/system/cpu/cpuX/topology/core_cpus is deprecated in favor
of thread_siblings, so probe thread_siblings before falling back on
core_cpus.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/util/smt.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/tools/perf/util/smt.c b/tools/perf/util/smt.c
index 2636be65305a..2b0a36ebf27a 100644
--- a/tools/perf/util/smt.c
+++ b/tools/perf/util/smt.c
@@ -79,11 +79,10 @@ int smt_on(void)
 		char fn[256];
 
 		snprintf(fn, sizeof fn,
-			"devices/system/cpu/cpu%d/topology/core_cpus", cpu);
+			"devices/system/cpu/cpu%d/topology/thread_siblings", cpu);
 		if (sysfs__read_str(fn, &str, &strlen) < 0) {
 			snprintf(fn, sizeof fn,
-				"devices/system/cpu/cpu%d/topology/thread_siblings",
-				cpu);
+				"devices/system/cpu/cpu%d/topology/core_cpus", cpu);
 			if (sysfs__read_str(fn, &str, &strlen) < 0)
 				continue;
 		}
-- 
2.34.0.rc2.393.gf8c9666880-goog
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