perf test: Add test for counting open syscalls

To test the use of the perf_evsel class on something other than
the tools from where we refactored code to create it.

It calls open() N times and then checks if the event created to
monitor it returns N events.

[acme@felicio linux]$ perf test
 1: vmlinux symtab matches kallsyms: Ok
 2: detect open syscall event: Ok
[acme@felicio linux]$

It does.

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Han Pingtian <phan@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 83 insertions, 0 deletions

diff --git a/tools/perf/builtin-test.c b/tools/perf/builtin-test.c
index e0c3f471f22d..6c991529f62b 100644
--- a/tools/perf/builtin-test.c
+++ b/tools/perf/builtin-test.c
@@ -234,6 +234,85 @@ out:
         return err;
 }
 
+#include "util/evsel.h"
+#include <sys/types.h>
+
+static int trace_event__id(const char *event_name)
+{
+        char *filename;
+        int err = -1, fd;
+
+        if (asprintf(&filename,
+                     "/sys/kernel/debug/tracing/events/syscalls/%s/id",
+                     event_name) < 0)
+                return -1;
+
+        fd = open(filename, O_RDONLY);
+        if (fd >= 0) {
+                char id[16];
+                if (read(fd, id, sizeof(id)) > 0)
+                        err = atoi(id);
+                close(fd);
+        }
+
+        free(filename);
+        return err;
+}
+
+static int test__open_syscall_event(void)
+{
+        int err = -1, fd;
+        struct thread_map *threads;
+        struct perf_evsel *evsel;
+        unsigned int nr_open_calls = 111, i;
+        int id = trace_event__id("sys_enter_open");
+
+        if (id < 0) {
+                pr_debug("trace_event__id(\"sys_enter_open\") ");
+                return -1;
+        }
+
+        threads = thread_map__new(-1, getpid());
+        if (threads == NULL) {
+                pr_debug("thread_map__new ");
+                return -1;
+        }
+
+        evsel = perf_evsel__new(PERF_TYPE_TRACEPOINT, id, 0);
+        if (evsel == NULL) {
+                pr_debug("perf_evsel__new ");
+                goto out_thread_map_delete;
+        }
+
+        if (perf_evsel__open_per_thread(evsel, threads) < 0) {
+                pr_debug("perf_evsel__open_per_thread ");
+                goto out_evsel_delete;
+        }
+
+        for (i = 0; i < nr_open_calls; ++i) {
+                fd = open("/etc/passwd", O_RDONLY);
+                close(fd);
+        }
+
+        if (perf_evsel__read_on_cpu(evsel, 0, 0) < 0) {
+                pr_debug("perf_evsel__open_read_on_cpu ");
+                goto out_close_fd;
+        }
+
+        if (evsel->counts->cpu[0].val != nr_open_calls)
+                pr_debug("perf_evsel__read_on_cpu: expected to intercept %d calls, got %Ld ",
+                         nr_open_calls, evsel->counts->cpu[0].val);
+        
+        err = 0;
+out_close_fd:
+        perf_evsel__close_fd(evsel, 1, threads->nr);
+out_evsel_delete:
+        perf_evsel__delete(evsel);
+out_thread_map_delete:
+        thread_map__delete(threads);
+        return err;
+}
+
 static struct test {
         const char *desc;
         int (*func)(void);
@@ -243,6 +322,10 @@ static struct test {
                 .func = test__vmlinux_matches_kallsyms,
         },
         {
+                .desc = "detect open syscall event",
+                .func = test__open_syscall_event,
+        },
+        {
                 .func = NULL,
         },
 };