tools/testing/selftests/ftrace/test.d/remotes/hotplug.tc

#!/bin/sh
# SPDX-License-Identifier: GPL-2.0
# description: Test trace remote read with an offline CPU
# requires: remotes/test

. $TEST_DIR/remotes/functions

hotunplug_one_cpu()
{
	[ "$(get_cpu_ids | wc -l)" -ge 2 ] || return 1

	for cpu in $(get_cpu_ids); do
		echo 0 > /sys/devices/system/cpu/cpu$cpu/online || return 1
		break
	done

	echo $cpu
}

# Check non-consuming and consuming read
check_read()
{
    for i in $(seq 1 8); do
        echo $i > write_event
    done

    check_trace 1 8 trace

    output=$(dump_trace_pipe)
    check_trace 1 8 $output
    rm $output
}

test_hotplug()
{
    echo 0 > trace
    assert_loaded

    #
    # Test a trace buffer containing an offline CPU
    #

    cpu=$(hotunplug_one_cpu) || exit_unsupported
    trap "echo 1 > /sys/devices/system/cpu/cpu$cpu/online" EXIT

    check_read

    #
    # Test a trace buffer with a missing CPU
    #

    reload_remote

    check_read

    #
    # Test a trace buffer with a CPU added later
    #

    echo 1 > /sys/devices/system/cpu/cpu$cpu/online
    trap "" EXIT
    assert_loaded

    check_read

    # Test if the ring-buffer for the newly added CPU is both writable and
    # readable
    for i in $(seq 1 8); do
        taskset -c $cpu echo $i > write_event
    done

    cd per_cpu/cpu$cpu/

    check_trace 1 8 trace

    output=$(dump_trace_pipe)
    check_trace 1 8 $output
    rm $output

    cd -
}

if [ -z "$SOURCE_REMOTE_TEST" ]; then
    set -e

    setup_remote_test
    test_hotplug
fi