1#!/bin/sh
2# SPDX-License-Identifier: GPL-2.0
3# description: Change the ringbuffer sub-buffer size
4# requires: buffer_subbuf_size_kb
5# flags: instance
6
7get_buffer_data_size() {
8	sed -ne 's/^.*data.*size:\([0-9][0-9]*\).*/\1/p' events/header_page
9}
10
11get_buffer_data_offset() {
12	sed -ne 's/^.*data.*offset:\([0-9][0-9]*\).*/\1/p' events/header_page
13}
14
15get_event_header_size() {
16	type_len=`sed -ne 's/^.*type_len.*:[^0-9]*\([0-9][0-9]*\).*/\1/p' events/header_event`
17	time_len=`sed -ne 's/^.*time_delta.*:[^0-9]*\([0-9][0-9]*\).*/\1/p' events/header_event`
18	array_len=`sed -ne 's/^.*array.*:[^0-9]*\([0-9][0-9]*\).*/\1/p' events/header_event`
19	total_bits=$((type_len+time_len+array_len))
20	total_bits=$((total_bits+7))
21	echo $((total_bits/8))
22}
23
24get_print_event_buf_offset() {
25	sed -ne 's/^.*buf.*offset:\([0-9][0-9]*\).*/\1/p' events/ftrace/print/format
26}
27
28event_header_size=`get_event_header_size`
29print_header_size=`get_print_event_buf_offset`
30
31data_offset=`get_buffer_data_offset`
32
33marker_meta=$((event_header_size+print_header_size))
34
35make_str() {
36        cnt=$1
37	printf -- 'X%.0s' $(seq $cnt)
38}
39
40write_buffer() {
41	size=$1
42
43	str=`make_str $size`
44
45	# clear the buffer
46	echo > trace
47
48	# write the string into the marker
49	echo $str > trace_marker
50
51	echo $str
52}
53
54test_buffer() {
55	size_kb=$1
56	page_size=$((size_kb*1024))
57
58	size=`get_buffer_data_size`
59
60	# the size must be greater than or equal to page_size - data_offset
61	page_size=$((page_size-data_offset))
62	if [ $size -lt $page_size ]; then
63		exit fail
64	fi
65
66	# Now add a little more the meta data overhead will overflow
67
68	str=`write_buffer $size`
69
70	# Make sure the line was broken
71	new_str=`awk ' /tracing_mark_write:/ { sub(/^.*tracing_mark_write: /,"");printf "%s", $0; exit}' trace`
72
73	if [ "$new_str" = "$str" ]; then
74		exit fail;
75	fi
76
77	# Make sure the entire line can be found
78	new_str=`awk ' /tracing_mark_write:/ { sub(/^.*tracing_mark_write: /,"");printf "%s", $0; }' trace`
79
80	if [ "$new_str" != "$str" ]; then
81		exit fail;
82	fi
83}
84
85ORIG=`cat buffer_subbuf_size_kb`
86
87# Could test bigger sizes than 32K, but then creating the string
88# to write into the ring buffer takes too long
89for a in 4 8 16 32 ; do
90	echo $a > buffer_subbuf_size_kb
91	test_buffer $a
92done
93
94echo $ORIG > buffer_subbuf_size_kb
95
96