diff mbox series

[14/14] ringbuffer/selftest: Add basic selftest to test chaning subbuf order

Message ID 20231210040452.274868572@goodmis.org
State New
Headers
Series ring-buffer/tracing: Allow ring buffer to have bigger sub buffers |

Commit Message

Steven Rostedt Dec. 10, 2023, 3:54 a.m. UTC 
  From: "Steven Rostedt (Google)" <rostedt@goodmis.org>

Add a self test that will write into the trace buffer with differ trace
sub buffer order sizes.

Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 .../ftrace/test.d/00basic/ringbuffer_order.tc | 46 +++++++++++++++++++
 1 file changed, 46 insertions(+)
 create mode 100644 tools/testing/selftests/ftrace/test.d/00basic/ringbuffer_order.tc

Comments

Mathieu Desnoyers Dec. 10, 2023, 2:26 p.m. UTC | #1 
On 2023-12-09 22:54, Steven Rostedt wrote:
[...]
> +get_buffer_data_size() {
> +	sed -ne 's/^.*data.*size:\([0-9][0-9]*\).*/\1/p' events/header_page
> +}
> +
> +a="1234567890"
> +
> +make_str() {
> +        cnt=$1
> +        s=""
> +        while [ $cnt -gt 10 ]; do
> +                s="${s}${a}"
> +                cnt=$((cnt-10))
> +        done
> +        while [ $cnt -gt 0 ]; do
> +                s="${s}X"
> +                cnt=$((cnt-1))
> +        done
> +        echo -n $s
> +}
> +
> +test_buffer() {
> +
> +	size=`get_buffer_data_size`
> +
> +	str=`make_str $size`
> +
> +	echo $str > trace_marker
> +
> +	grep -q $a trace

This test has no clue if the record was truncated or not.

It basically repeats the string

"1234567890" until it fills the subbuffer size and pads with
XXXX as needed as trace marker payload, but the grep looks for the
"1234567890" pattern only.

The test should be extended to validate whether the trace marker
payload was truncated or not, otherwise it is of limited value.

Thanks,

Mathieu
Steven Rostedt Dec. 10, 2023, 3:44 p.m. UTC | #2 
On Sun, 10 Dec 2023 09:26:13 -0500
Mathieu Desnoyers <mathieu.desnoyers@efficios.com> wrote:


> This test has no clue if the record was truncated or not.
> 
> It basically repeats the string
> 
> "1234567890" until it fills the subbuffer size and pads with
> XXXX as needed as trace marker payload, but the grep looks for the
> "1234567890" pattern only.
> 
> The test should be extended to validate whether the trace marker
> payload was truncated or not, otherwise it is of limited value.

It can be, but for now it's just testing to make sure it doesn't crash. I
ran out of time, and if someone else wants to extend this, go ahead.
Currently, my testing has been just manual observations. I threw this in
just to have some kind of smoke test applied.

I agree with the API changes, and will update that. But given that this has
been two years and never applied, is because nobody has the time to work on
this. The reason I'm pushing for this now, is because Kent hit the limit in
his work. Knowing that he would not have hit this limit if these patches
were applied, I feel more urgency on getting them in. But this is all on my
own time, not part of my Employer (hence why I'm working on the weekend).

-- Steve
diff mbox series

Patch

diff --git a/tools/testing/selftests/ftrace/test.d/00basic/ringbuffer_order.tc b/tools/testing/selftests/ftrace/test.d/00basic/ringbuffer_order.tc
new file mode 100644
index 000000000000..c0d76dc724d3
--- /dev/null
+++ b/tools/testing/selftests/ftrace/test.d/00basic/ringbuffer_order.tc
@@ -0,0 +1,46 @@ 
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# description: Change the ringbuffer size
+# requires: buffer_subbuf_order
+# flags: instance
+
+get_buffer_data_size() {
+	sed -ne 's/^.*data.*size:\([0-9][0-9]*\).*/\1/p' events/header_page
+}
+
+a="1234567890"
+
+make_str() {
+        cnt=$1
+        s=""
+        while [ $cnt -gt 10 ]; do
+                s="${s}${a}"
+                cnt=$((cnt-10))
+        done
+        while [ $cnt -gt 0 ]; do
+                s="${s}X"
+                cnt=$((cnt-1))
+        done
+        echo -n $s
+}
+
+test_buffer() {
+
+	size=`get_buffer_data_size`
+
+	str=`make_str $size`
+
+	echo $str > trace_marker
+
+	grep -q $a trace
+}
+
+ORIG=`cat buffer_subbuf_order`
+
+for a in `seq 0 4`; do
+	echo 0 > buffer_subbuf_order
+	test_buffer
+done
+
+echo $ORIG > buffer_subbuf_order
+