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Subject[tip:perf/core] perf test: Fix test case 23 for s390 z/VM or KVM guests
Commit-ID:  b3be39c51cc58eb60c698cf64987e9d465a9263a
Gitweb: https://git.kernel.org/tip/b3be39c51cc58eb60c698cf64987e9d465a9263a
Author: Thomas Richter <tmricht@linux.vnet.ibm.com>
AuthorDate: Tue, 13 Feb 2018 16:14:19 +0100
Committer: Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Fri, 16 Feb 2018 15:16:57 -0300

perf test: Fix test case 23 for s390 z/VM or KVM guests

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@linux.vnet.ibm.com>
Reviewed-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Link: http://lkml.kernel.org/r/20180213151419.80737-4-tmricht@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
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 3bf7b14..c7115d3 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) {
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