linux-kernel - Re: [PATCH v4] tracing/selftests: Add test to test the trace

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Message-Id: <20231214075926.e3969c8746068953fe910ed0@kernel.org>
Date:   Thu, 14 Dec 2023 07:59:26 +0900
From:   Masami Hiramatsu (Google) <mhiramat@...nel.org>
To:     Steven Rostedt <rostedt@...dmis.org>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        Linux Trace Kernel <linux-trace-kernel@...r.kernel.org>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
        Shuah Khan <shuah@...nel.org>, linux-kselftest@...r.kernel.org
Subject: Re: [PATCH v4] tracing/selftests: Add test to test the trace_marker

On Wed, 13 Dec 2023 11:15:27 -0500
Steven Rostedt <rostedt@...dmis.org> wrote:

> From: "Steven Rostedt (Google)" <rostedt@...dmis.org>
> 
> Add a test that writes longs strings, some over the size of the sub buffer
> and make sure that the entire content is there.

This looks good to me. and tested.

Acked-by: Masami Hiramatsu (Google) <mhiramat@...nel.org>
Tested-by: Masami Hiramatsu (Google) <mhiramat@...nel.org>

Thank you,

> 
> Signed-off-by: Steven Rostedt (Google) <rostedt@...dmis.org>
> ---
> Changes since v3: https://lore.kernel.org/linux-trace-kernel/20231212192317.0fb6b101@gandalf.local.home
> 
> - Removed / */ from regex, to catch more than one space added to the
>   beginning of the print. This would have caught the bug of using "%*s"
>   instead of "%.*s". Luckily, the trace_printk test caught that.
> 
>  .../ftrace/test.d/00basic/trace_marker.tc     | 82 +++++++++++++++++++
>  1 file changed, 82 insertions(+)
>  create mode 100755 tools/testing/selftests/ftrace/test.d/00basic/trace_marker.tc
> 
> 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..9aa0db2b84fc
> --- /dev/null
> +++ b/tools/testing/selftests/ftrace/test.d/00basic/trace_marker.tc
> @@ -0,0 +1,82 @@
> +#!/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`
> +
> +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
> +
> +	# 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
> 


-- 
Masami Hiramatsu (Google) <mhiramat@...nel.org>