On Wed, 13 Dec 2023 09:33:18 +0900 Masami Hiramatsu (Google) mhiramat@kernel.org wrote:
On Tue, 12 Dec 2023 15:16:32 -0500 Steven Rostedt rostedt@goodmis.org wrote:
From: "Steven Rostedt (Google)" rostedt@goodmis.org
Now that the trace_marker can write up to the max size of the sub buffer. Add a test to see if it actually can happen.
The README is updated to state that the trace_marker writes can be broken up, and the test checks the README for that statement so that it does not fail on older kernels that does not support this.
I think it is better that the feature patch include README update or a separate patch because it identifies the feature is implemented or not.
No need, my v3 removes all this as I found it will not work with the sub buffer resize update.
If the README does not have the specified update, the test will still test if all the string is written, as that should work with older kernels.
Cc: Shuah Khan shuah@kernel.org Cc: linux-kselftest@vger.kernel.org Signed-off-by: Steven Rostedt (Google) rostedt@goodmis.org
Changes since v1: https://lore.kernel.org/linux-trace-kernel/20231212135441.0337c3e9@gandalf.l...
- Fix description as it was a cut and paste from the subbuffer size tests that are not added yet.
kernel/trace/trace.c | 1 + .../ftrace/test.d/00basic/trace_marker.tc | 112 ++++++++++++++++++ 2 files changed, 113 insertions(+) create mode 100755 tools/testing/selftests/ftrace/test.d/00basic/trace_marker.tc
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 2f8d59834c00..cbfcdd882590 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -5595,6 +5595,7 @@ static const char readme_msg[] = " delta: Delta difference against a buffer-wide timestamp\n" " absolute: Absolute (standalone) timestamp\n" "\n trace_marker\t\t- Writes into this file writes into the kernel buffer\n"
- "\n May be broken into multiple events based on sub-buffer size.\n" "\n trace_marker_raw\t\t- Writes into this file writes binary data into the kernel buffer\n" " tracing_cpumask\t- Limit which CPUs to trace\n" " instances\t\t- Make sub-buffers with: mkdir instances/foo\n"
diff --git a/tools/testing/selftests/ftrace/test.d/00basic/trace_marker.tc b/tools/testing/selftests/ftrace/test.d/00basic/trace_marker.tc new file mode 100755 index 000000000000..bf7f6f50c88a --- /dev/null +++ b/tools/testing/selftests/ftrace/test.d/00basic/trace_marker.tc @@ -0,0 +1,112 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0 +# description: Basic tests on writing to trace_marker +# requires: trace_marker +# flags: instance
+get_buffer_data_size() {
- sed -ne 's/^.*data.*size:([0-9][0-9]*).*/\1/p' events/header_page
+}
+get_buffer_data_offset() {
- sed -ne 's/^.*data.*offset:([0-9][0-9]*).*/\1/p' events/header_page
+}
+get_event_header_size() {
- type_len=`sed -ne 's/^.*type_len.*:[^0-9]*([0-9][0-9]*).*/\1/p' events/header_event`
- time_len=`sed -ne 's/^.*time_delta.*:[^0-9]*([0-9][0-9]*).*/\1/p' events/header_event`
- array_len=`sed -ne 's/^.*array.*:[^0-9]*([0-9][0-9]*).*/\1/p' events/header_event`
- total_bits=$((type_len+time_len+array_len))
- total_bits=$((total_bits+7))
- echo $((total_bits/8))
+}
+get_print_event_buf_offset() {
- sed -ne 's/^.*buf.*offset:([0-9][0-9]*).*/\1/p' events/ftrace/print/format
+}
+event_header_size=`get_event_header_size` +print_header_size=`get_print_event_buf_offset`
+# Find the README +README="" +if [ -f README ]; then
- README="README"
+# instance? +elif [ -f ../../README ]; then
- README="../../README"
+fi
+testone=0 +if [ ! -z "$README" ]; then
- if grep -q "May be broken into multiple events based on sub-buffer size" $README; then
testone=1- fi
+fi
Hmm, this should be a common function if we see this pattern somewhere else.
I remove this in the next version. But yeah, there's a bug in the selftests that if a test has an instance flag set, then the requirements will not check the README, as the instance has no README.
+data_offset=`get_buffer_data_offset`
+marker_meta=$((event_header_size+print_header_size))
+make_str() {
cnt=$1- # subtract two for \n\0 as marker adds these
- cnt=$((cnt-2))
- printf -- 'X%.0s' $(seq $cnt)
+}
+write_buffer() {
- size=$1
- str=`make_str $size`
- # clear the buffer
- echo > trace
- # write the string into the marker
- echo -n $str > trace_marker
- echo $str
+}
+test_buffer() {
- size=`get_buffer_data_size`
- oneline_size=$((size-marker_meta))
- echo size = $size
- echo meta size = $marker_meta
- if [ $testone -eq 1 ]; then
echo oneline size = $oneline_sizestr=`write_buffer $oneline_size`# Should be in one single eventnew_str=`awk ' /tracing_mark_write:/ { sub(/^.*tracing_mark_write: */,"");printf "%s", $0; exit}' trace`if [ "$new_str" != "$str" ]; thenexit fail;fi- fi
Or, maybe we can split this part into another testcase.
I removed this anyway. But it may come back in the future if we can get dynamically sized trace_seq working.
-- Steve
- # Now add a little more the meta data overhead will overflow
- str=`write_buffer $size`
- # Make sure the line was broken
- new_str=`awk ' /tracing_mark_write:/ { sub(/^.*tracing_mark_write: /,"");printf "%s", $0; exit}' trace`
- if [ "$new_str" = "$str" ]; then
exit fail;- fi
- # Make sure the entire line can be found
- new_str=`awk ' /tracing_mark_write:/ { sub(/^.*tracing_mark_write: */,"");printf "%s", $0; }' trace`
- if [ "$new_str" != "$str" ]; then
exit fail;- fi
+}
+test_buffer
-- 2.42.0