[LTTng-modules,v2] Add throughput test to LTTng

Message ID 1473766010-23680-1-git-send-email-mohamad.gebai@gmail.com
State New
Headers show

Commit Message

Mohamad Gebai Sept. 13, 2016, 11:26 a.m. UTC
- Create the lttng-test subdirectory under /proc for testing purposes.

- Create the procfs throughput file. Start a throughput test by writing
  the number of iterations for the test. Read from this file to get the
  total duration. Note that the test automatically tries to reach a steady
  state before benchmarking.

Signed-off-by: Mohamad Gebai <mohamad.gebai at gmail.com>
---
 instrumentation/events/lttng-module/lttng-test.h |   8 ++
 tests/probes/lttng-test.c                        | 120 ++++++++++++++++++++---
 2 files changed, 117 insertions(+), 11 deletions(-)

Patch

diff --git a/instrumentation/events/lttng-module/lttng-test.h b/instrumentation/events/lttng-module/lttng-test.h
index 05d028c..54b4404 100644
--- a/instrumentation/events/lttng-module/lttng-test.h
+++ b/instrumentation/events/lttng-module/lttng-test.h
@@ -48,6 +48,14 @@  LTTNG_TRACEPOINT_EVENT(lttng_test_filter_event,
 	)
 )
 
+LTTNG_TRACEPOINT_EVENT(lttng_test_throughput,
+    TP_PROTO(int anint),
+    TP_ARGS(anint),
+    TP_FIELDS(
+        ctf_integer(int, intfield, anint)
+    )
+)
+
 #endif /*  LTTNG_TRACE_LTTNG_TEST_H */
 
 /* This part must be outside protection */
diff --git a/tests/probes/lttng-test.c b/tests/probes/lttng-test.c
index 54be4c7..b42ea1c 100644
--- a/tests/probes/lttng-test.c
+++ b/tests/probes/lttng-test.c
@@ -39,12 +39,18 @@ 
 #include <instrumentation/events/lttng-module/lttng-test.h>
 
 DEFINE_TRACE(lttng_test_filter_event);
+DEFINE_TRACE(lttng_test_throughput);
 
-#define LTTNG_TEST_FILTER_EVENT_FILE	"lttng-test-filter-event"
+#define LTTNG_TEST_PROCFS_DIR           "lttng-test"
+#define LTTNG_TEST_FILTER_EVENT_FILE    "filter-event"
+/* Do a throughput benchmark by writing to this file the number of events.
+ * Read to get the duration of the benchmark. */
+#define LTTNG_TEST_THROUGHPUT_FILE      "throughput"
 
 #define LTTNG_WRITE_COUNT_MAX	64
 
-static struct proc_dir_entry *lttng_test_filter_event_dentry;
+static struct proc_dir_entry *lttng_test_dentry;
+static u64 latest_throughput_results = 0;
 
 static
 void trace_test_event(unsigned int nr_iter)
@@ -60,6 +66,24 @@  void trace_test_event(unsigned int nr_iter)
 	}
 }
 
+static
+void lttng_throughput_test(unsigned int nr_iter)
+{
+	int i;
+	u64 start_time, end_time;
+
+	/* Warm up and get to a steady state */
+	for (i = 0; i < nr_iter / 2; i++)
+		trace_lttng_test_throughput(i);
+
+	start_time = trace_clock_read64();
+	for (i = 0; i < nr_iter; i++)
+		trace_lttng_test_throughput(i);
+	end_time = trace_clock_read64();
+
+	latest_throughput_results = end_time - start_time;
+}
+
 /**
  * lttng_filter_event_write - trigger a lttng_test_filter_event
  * @file: file pointer
@@ -90,10 +114,73 @@  end:
 	return written;
 }
 
+/**
+ * lttng_throughput_test_write - trigger a lttng_throughput_test
+ * @file: file pointer
+ * @user_buf: user string
+ * @count: length to copy
+ *
+ * Return -1 on error, with EFAULT errno. Returns count on success.
+ */
+static
+ssize_t lttng_throughput_test_write(struct file *file,
+                                    const char __user *user_buf,
+                                    size_t count, loff_t *ppos)
+{
+	unsigned int nr_iter;
+	ssize_t written;
+	int ret;
+
+	/* Get the number of iterations */
+	ret = lttng_kstrtouint_from_user(user_buf, count, 10, &nr_iter);
+	if (ret) {
+		written = ret;
+		goto end;
+	}
+	/* Do throughput test */
+	lttng_throughput_test(nr_iter);
+	written = count;
+	*ppos += written;
+
+end:
+    return written;
+}
+
+/**
+ * lttng_throughput_test_read - read latest results of throughput test
+ * @file: file pointer
+ * @user_buf: user string
+ * @count: length to copy
+ *
+ * Return -1 on error, with EFAULT errno. Returns count on success.
+ */
+static
+ssize_t lttng_throughput_test_read(struct file *file, char __user *user_buf,
+                           size_t count, loff_t *ppos)
+{
+	char buf[count];
+	ssize_t read_count = 0;
+
+	if (latest_throughput_results == 0)
+		goto end;
+
+	read_count += snprintf(buf, count, "%llu\n", latest_throughput_results);
+	copy_to_user(user_buf, buf, count);
+	latest_throughput_results = 0;
+
+end:
+    return read_count;
+}
+
 static const struct file_operations lttng_test_filter_event_operations = {
 	.write = lttng_test_filter_event_write,
 };
 
+static const struct file_operations lttng_throughput_test_operations = {
+	.write = lttng_throughput_test_write,
+	.read = lttng_throughput_test_read,
+};
+
 static
 int __init lttng_test_init(void)
 {
@@ -101,22 +188,33 @@  int __init lttng_test_init(void)
 
 	(void) wrapper_lttng_fixup_sig(THIS_MODULE);
 	wrapper_vmalloc_sync_all();
-	lttng_test_filter_event_dentry =
-			proc_create_data(LTTNG_TEST_FILTER_EVENT_FILE,
-				S_IRUGO | S_IWUGO, NULL,
-				&lttng_test_filter_event_operations, NULL);
-	if (!lttng_test_filter_event_dentry) {
-		printk(KERN_ERR "Error creating LTTng test filter file\n");
+	lttng_test_dentry = proc_mkdir(LTTNG_TEST_PROCFS_DIR, NULL);
+	if (!lttng_test_dentry) {
+		printk(KERN_ERR "Error creating LTTng test directory\n");
 		ret = -ENOMEM;
 		goto error;
 	}
+	if (!proc_create_data(LTTNG_TEST_FILTER_EVENT_FILE,
+				S_IRUGO | S_IWUGO, lttng_test_dentry,
+				&lttng_test_filter_event_operations, NULL)) {
+		printk(KERN_ERR "Error creating LTTng test filter file\n");
+		ret = -ENOMEM;
+		goto error_events;
+	}
+	if (!proc_create_data(LTTNG_TEST_THROUGHPUT_FILE,
+				S_IRUGO | S_IWUGO, lttng_test_dentry,
+				&lttng_throughput_test_operations, NULL)) {
+		printk(KERN_ERR "Error creating LTTng test throughput file\n");
+		ret = -ENOMEM;
+		goto error_events;
+	}
 	ret = __lttng_events_init__lttng_test();
 	if (ret)
 		goto error_events;
 	return ret;
 
 error_events:
-	remove_proc_entry(LTTNG_TEST_FILTER_EVENT_FILE, NULL);
+	remove_proc_subtree(LTTNG_TEST_PROCFS_DIR, NULL);
 error:
 	return ret;
 }
@@ -127,8 +225,8 @@  static
 void __exit lttng_test_exit(void)
 {
 	__lttng_events_exit__lttng_test();
-	if (lttng_test_filter_event_dentry)
-		remove_proc_entry(LTTNG_TEST_FILTER_EVENT_FILE, NULL);
+	if (lttng_test_dentry)
+		remove_proc_subtree(LTTNG_TEST_PROCFS_DIR, NULL);
 }
 
 module_exit(lttng_test_exit);