On Mon, 26 Jan 2026 10:44:04 +0000
Vincent Donnefort <[email protected]> wrote:
> --- /dev/null
> +++ b/tools/testing/selftests/ftrace/test.d/remotes/trace.tc
> @@ -0,0 +1,127 @@
> +#!/bin/sh
> +# SPDX-License-Identifier: GPL-2.0
> +# description: Test trace remote non-consuming read
> +# requires: remotes/test
> +
> +. $TEST_DIR/remotes/functions
> +
> +test_trace()
> +{
> + echo 0 > tracing_on
> + assert_unloaded
> +
> + echo 7 > buffer_size_kb
> + echo 1 > tracing_on
> + assert_loaded
> +
> + # Simple test: Emit few events and try to read them
> + for i in $(seq 1 8); do
> + echo $i > write_event
> + done
> +
> + check_trace 1 8 trace
> +
> + #
> + # Test interaction with consuming read
> + #
> +
> + cat trace_pipe > /dev/null &
> + pid=$!
> +
> + sleep 1
> + kill $pid
> +
> + test $(wc -l < trace) -eq 0
> +
> + for i in $(seq 16 32); do
> + echo $i > write_event
> + done
> +
> + check_trace 16 32 trace
> +
> + #
> + # Test interaction with reset
> + #
> +
> + echo 0 > trace
> +
> + test $(wc -l < trace) -eq 0
> +
> + for i in $(seq 1 8); do
> + echo $i > write_event
> + done
> +
> + check_trace 1 8 trace
> +
> + #
> + # Test interaction with lost events
> + #
> +
> + # Ensure the writer is not on the reader page by reloading the buffer
> + echo 0 > tracing_on
> + echo 0 > trace
> + assert_unloaded
> + echo 1 > tracing_on
> + assert_loaded
> +
> + # Ensure ring-buffer overflow by emitting events from the same CPU
> + for cpu in $(get_cpu_ids); do
> + break
> + done
> +
> + events_per_page=$(($(get_page_size) / $(get_selftest_event_size))) #
> Approx: does not take TS into account
> + nr_events=$(($events_per_page * 2))
> + for i in $(seq 1 $nr_events); do
> + taskset -c $cpu echo $i > write_event
> + done
> +
> + id=$(sed -n -e '1s/\[[0-9]*\]\s*[0-9]*.[0-9]*: [a-z]*
> id=\([0-9]*\)/\1/p' trace)
> + test $id -ne 1
> +
> + check_trace $id $nr_events trace
> +
> + #
> + # Test per-CPU interface
> + #
> + echo 0 > trace
> +
> + for cpu in $(get_cpu_ids) ; do
> + taskset -c $cpu echo $cpu > write_event
> + done
> +
> + for cpu in $(get_cpu_ids); do
> + cd per_cpu/cpu$cpu/
> +
> + check_trace $cpu $cpu trace
> +
> + cd - > /dev/null
> + done
> +
> + #
> + # Test with hotplug
> + #
> +
> + [ "$(get_cpu_ids | wc -l)" -ge 2 ] || return 0
> +
> + echo 0 > trace
> +
> + for cpu in $(get_cpu_ids); do
> + echo 0 > /sys/devices/system/cpu/cpu$cpu/online
Note, my test VM doesn't have cpu0/online, so this needs to test for the
existence of these files:
./ftracetest: 105:
/work/git/linux.git/tools/testing/selftests/ftrace/test.d/remotes/trace_pipe.tc:
cannot create /sys/devices/system/cpu/cpu0/online: Permission denied
-- Steve
> + break
> + done
> +
> + for i in $(seq 1 8); do
> + echo $i > write_event
> + done
> +
> + check_trace 1 8 trace
> +
> + echo 1 > /sys/devices/system/cpu/cpu$cpu/online
> +}
> +
> +if [ -z "$SOURCE_REMOTE_TEST" ]; then
> + set -e
> +
> + setup_remote_test
> + test_trace
> +fi
