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-rw-r--r--tools/perf/arch/x86/util/topdown.c63
1 files changed, 63 insertions, 0 deletions
diff --git a/tools/perf/arch/x86/util/topdown.c b/tools/perf/arch/x86/util/topdown.c
new file mode 100644
index 000000000..2f3d96aa9
--- /dev/null
+++ b/tools/perf/arch/x86/util/topdown.c
@@ -0,0 +1,63 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <stdio.h>
+#include "api/fs/fs.h"
+#include "util/pmu.h"
+#include "util/topdown.h"
+
+/*
+ * Check whether we can use a group for top down.
+ * Without a group may get bad results due to multiplexing.
+ */
+bool arch_topdown_check_group(bool *warn)
+{
+ int n;
+
+ if (sysctl__read_int("kernel/nmi_watchdog", &n) < 0)
+ return false;
+ if (n > 0) {
+ *warn = true;
+ return false;
+ }
+ return true;
+}
+
+void arch_topdown_group_warn(void)
+{
+ fprintf(stderr,
+ "nmi_watchdog enabled with topdown. May give wrong results.\n"
+ "Disable with echo 0 > /proc/sys/kernel/nmi_watchdog\n");
+}
+
+#define TOPDOWN_SLOTS 0x0400
+
+static bool is_topdown_slots_event(struct evsel *counter)
+{
+ if (!counter->pmu_name)
+ return false;
+
+ if (strcmp(counter->pmu_name, "cpu"))
+ return false;
+
+ if (counter->core.attr.config == TOPDOWN_SLOTS)
+ return true;
+
+ return false;
+}
+
+/*
+ * Check whether a topdown group supports sample-read.
+ *
+ * Only Topdown metic supports sample-read. The slots
+ * event must be the leader of the topdown group.
+ */
+
+bool arch_topdown_sample_read(struct evsel *leader)
+{
+ if (!pmu_have_event("cpu", "slots"))
+ return false;
+
+ if (is_topdown_slots_event(leader))
+ return true;
+
+ return false;
+}