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author | Steven Rostedt (Google) <rostedt@goodmis.org> | 2023-12-19 13:54:29 -0500 |
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committer | Steven Rostedt (Google) <rostedt@goodmis.org> | 2023-12-21 11:04:15 -0500 |
commit | 2f84b39f48476615186af5b3220ad5a2c756679b (patch) | |
tree | 8006b5c599719b990807281a82233eb1c2d91f5b /tools/testing/selftests/ftrace/test.d/00basic/ringbuffer_subbuf_size.tc | |
parent | ringbuffer/selftest: Add basic selftest to test changing subbuf order (diff) | |
download | wireguard-linux-2f84b39f48476615186af5b3220ad5a2c756679b.tar.xz wireguard-linux-2f84b39f48476615186af5b3220ad5a2c756679b.zip |
tracing: Update subbuffer with kilobytes not page order
Using page order for deciding what the size of the ring buffer sub buffers
are is exposing a bit too much of the implementation. Although the sub
buffers are only allocated in orders of pages, allow the user to specify
the minimum size of each sub-buffer via kilobytes like they can with the
buffer size itself.
If the user specifies 3 via:
echo 3 > buffer_subbuf_size_kb
Then the sub-buffer size will round up to 4kb (on a 4kb page size system).
If they specify:
echo 6 > buffer_subbuf_size_kb
The sub-buffer size will become 8kb.
and so on.
Link: https://lore.kernel.org/linux-trace-kernel/20231219185631.809766769@goodmis.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Tzvetomir Stoyanov <tz.stoyanov@gmail.com>
Cc: Vincent Donnefort <vdonnefort@google.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Diffstat (limited to 'tools/testing/selftests/ftrace/test.d/00basic/ringbuffer_subbuf_size.tc')
-rw-r--r-- | tools/testing/selftests/ftrace/test.d/00basic/ringbuffer_subbuf_size.tc | 95 |
1 files changed, 95 insertions, 0 deletions
diff --git a/tools/testing/selftests/ftrace/test.d/00basic/ringbuffer_subbuf_size.tc b/tools/testing/selftests/ftrace/test.d/00basic/ringbuffer_subbuf_size.tc new file mode 100644 index 000000000000..d44d09a33a74 --- /dev/null +++ b/tools/testing/selftests/ftrace/test.d/00basic/ringbuffer_subbuf_size.tc @@ -0,0 +1,95 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0 +# description: Change the ringbuffer sub-buffer size +# requires: buffer_subbuf_size_kb +# 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 + 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 $str > trace_marker + + echo $str +} + +test_buffer() { + size_kb=$1 + page_size=$((size_kb*1024)) + + size=`get_buffer_data_size` + + # the size must be greater than or equal to page_size - data_offset + page_size=$((page_size-data_offset)) + if [ $size -lt $page_size ]; then + exit fail + fi + + # 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 +} + +ORIG=`cat buffer_subbuf_size_kb` + +# Could test bigger sizes than 32K, but then creating the string +# to write into the ring buffer takes too long +for a in 4 8 16 32 ; do + echo $a > buffer_subbuf_size_kb + test_buffer $a +done + +echo $ORIG > buffer_subbuf_size_kb + |