[PATCH 4/4] perf test: Fix test case 23 for s390 z/VM or KVM guests

From: Thomas Richter
Date: Tue Feb 13 2018 - 10:14:44 EST


On s390 perf can be executed on a LPAR with support
for hardware events (i. e. cycles) or on a z/VM or KVM guest
where no hardware events are supported. In this
environment use software event named cpu-clock
for this test case.

Use the cpuid infrastructure functions to determine
the cpuid on s390 which contains an indication of the
cpu counter facility availability.

Signed-off-by: Thomas Richter <tmricht@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Hendrik Brueckner <brueckner@xxxxxxxxxxxxxxxxxx>
---
tools/perf/tests/code-reading.c | 33 +++++++++++++++++++++++++++++----
1 file changed, 29 insertions(+), 4 deletions(-)

diff --git a/tools/perf/tests/code-reading.c b/tools/perf/tests/code-reading.c
index 3bf7b145b826..c7115d369511 100644
--- a/tools/perf/tests/code-reading.c
+++ b/tools/perf/tests/code-reading.c
@@ -482,6 +482,34 @@ static void fs_something(void)
}
}

+static const char *do_determine_event(bool excl_kernel)
+{
+ const char *event = excl_kernel ? "cycles:u" : "cycles";
+
+#ifdef __s390x__
+ char cpuid[128], model[16], model_c[16], cpum_cf_v[16];
+ unsigned int family;
+ int ret, cpum_cf_a;
+
+ if (get_cpuid(cpuid, sizeof(cpuid)))
+ goto out_clocks;
+ ret = sscanf(cpuid, "%*[^,],%u,%[^,],%[^,],%[^,],%x", &family, model_c,
+ model, cpum_cf_v, &cpum_cf_a);
+ if (ret != 5) /* Not available */
+ goto out_clocks;
+ if (excl_kernel && (cpum_cf_a & 4))
+ return event;
+ if (!excl_kernel && (cpum_cf_a & 2))
+ return event;
+
+ /* Fall through: missing authorization */
+out_clocks:
+ event = excl_kernel ? "cpu-clock:u" : "cpu-clock";
+
+#endif
+ return event;
+}
+
static void do_something(void)
{
fs_something();
@@ -592,10 +620,7 @@ static int do_test_code_reading(bool try_kcore)

perf_evlist__set_maps(evlist, cpus, threads);

- if (excl_kernel)
- str = "cycles:u";
- else
- str = "cycles";
+ str = do_determine_event(excl_kernel);
pr_debug("Parsing event '%s'\n", str);
ret = parse_events(evlist, str, NULL);
if (ret < 0) {
--
2.14.3