Re: [lttng-dev] [PATCH lttng-modules] Add throughput test to LTTng

[Julien Desfossez]

Hi,

See comments below

On 08-Sep-2016 01:27:42 PM, Mohamad Gebai wrote:
> - 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
>   result in nanoseconds. Note that the test automatically tries to reach
>   a steady state before benchmarking.
> 
> Signed-off-by: Mohamad Gebai 
> ---
>  instrumentation/events/lttng-module/lttng-test.h |   8 ++
>  tests/probes/lttng-test.c| 118 
> +--
>  2 files changed, 116 insertions(+), 10 deletions(-)
> 
> 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..dc59680 100644
> --- a/tests/probes/lttng-test.c
> +++ b/tests/probes/lttng-test.c
> @@ -23,6 +23,7 @@
>  #include 
>  #include 
>  #include 
> +#include 
>  #include 
>  
>  #include 
> @@ -39,12 +40,18 @@
>  #include 
>  
>  DEFINE_TRACE(lttng_test_filter_event);
> +DEFINE_TRACE(lttng_test_throughput);
>  
> -#define LTTNG_TEST_FILTER_EVENT_FILE "lttng-test-filter-event"

Note that a patch to update all the tests that use this file in
lttng-tools will be needed if we change the path of
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 the results in nanoseconds. */
> +#define LTTNG_TEST_THROUGHPUT_FILE  "throughput"
>  
>  #define LTTNG_WRITE_COUNT_MAX64
>  
> -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 +67,24 @@ void trace_test_event(unsigned int nr_iter)
>   }
>  }
>  
> +static
> +void lttng_throughput_test(unsigned int nr_iter)
> +{
> + int i;
> + ktime_t start_time, end_time;
> +
> + /* Warm up and get to a steady state */
> + for(i = 0; i < nr_iter / 2; i++)
for (i =...
> + trace_lttng_test_throughput(i);
> +
> + start_time = ktime_get();
Do we really want to use ktime_get() directly and not the
trace_clock_read64 wrapper instead ? It might be easier to correlate the
aggregated result from latest_throughput_results with the generated
events list if they use the same clock.

> + for(i = 0; i < nr_iter; i++)
for (i =...
> + trace_lttng_test_throughput(i);
> + end_time = ktime_get();
> +
> + latest_throughput_results = ktime_to_ns(end_time) - 
> ktime_to_ns(start_time);
> +}
> +
>  /**
>   * lttng_filter_event_write - trigger a lttng_test_filter_event
>   * @file: file pointer
> @@ -90,10 +115,72 @@ 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, _iter);
> + if (ret) {
> + written = ret;
> + goto end;
> + }
> + /* Do throughput test */
> + lttng_throughput_test(nr_iter);
> + written = count;
> + *ppos += written;
add new line here
> +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)
if (latest_...
> + goto end;
> +
> + read_count += snprintf(buf, 

[lttng-dev] [PATCH lttng-modules] Add throughput test to LTTng

[Mohamad Gebai]

- 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
  result in nanoseconds. Note that the test automatically tries to reach
  a steady state before benchmarking.

Signed-off-by: Mohamad Gebai 
---
 instrumentation/events/lttng-module/lttng-test.h |   8 ++
 tests/probes/lttng-test.c| 118 +--
 2 files changed, 116 insertions(+), 10 deletions(-)

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..dc59680 100644
--- a/tests/probes/lttng-test.c
+++ b/tests/probes/lttng-test.c
@@ -23,6 +23,7 @@
 #include 
 #include 
 #include 
+#include 
 #include 
 
 #include 
@@ -39,12 +40,18 @@
 #include 
 
 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 the results in nanoseconds. */
+#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 +67,24 @@ void trace_test_event(unsigned int nr_iter)
}
 }
 
+static
+void lttng_throughput_test(unsigned int nr_iter)
+{
+   int i;
+   ktime_t 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 = ktime_get();
+   for(i = 0; i < nr_iter; i++)
+   trace_lttng_test_throughput(i);
+   end_time = ktime_get();
+
+   latest_throughput_results = ktime_to_ns(end_time) - 
ktime_to_ns(start_time);
+}
+
 /**
  * lttng_filter_event_write - trigger a lttng_test_filter_event
  * @file: file pointer
@@ -90,10 +115,72 @@ 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, _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 =
-