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

Source file repositories/reference/linux-study-clean/tools/testing/selftests/ftrace/test.d/remotes/trace_pipe.tc

File Facts

System
Linux kernel
Corpus path
tools/testing/selftests/ftrace/test.d/remotes/trace_pipe.tc
Extension
.tc
Size
1974 bytes
Lines
103
Domain
Support Tooling And Documentation
Bucket
tools
Inferred role
Support Tooling And Documentation: tools
Status
atlas-only

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

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

. $TEST_DIR/remotes/functions

test_trace_pipe()
{
    echo 0 > tracing_on
    assert_unloaded

    # Emit events from the same CPU
    for cpu in $(get_cpu_ids); do
        break
    done

    #
    # Simple test: Emit enough events to fill few pages
    #

    echo 1024 > buffer_size_kb
    echo 1 > tracing_on
    assert_loaded

    events_per_page=$(($(get_page_size) / $(get_selftest_event_size)))
    nr_events=$(($events_per_page * 4))

    output=$(mktemp $TMPDIR/remote_test.XXXXXX)

    cat trace_pipe > $output &
    pid=$!

    for i in $(seq 1 $nr_events); do
        taskset -c $cpu echo $i > write_event
    done

    echo 0 > tracing_on
    sleep 1
    kill $pid

    check_trace 1 $nr_events $output

    rm $output

    #
    # Test interaction with lost events
    #

    assert_unloaded
    echo 7 > buffer_size_kb
    echo 1 > tracing_on
    assert_loaded

    nr_events=$((events_per_page * 2))
    for i in $(seq 1 $nr_events); do
        taskset -c $cpu echo $i > write_event
    done

    output=$(dump_trace_pipe)

    lost_events=$(sed -n -e '1s/CPU:.*\[LOST \([0-9]*\) EVENTS\]/\1/p' $output)
    test -n "$lost_events"

    id=$(sed -n -e '2s/\[[0-9]*\]\s*[0-9]*.[0-9]*: [a-z]* id=\([0-9]*\)/\1/p' $output)
    test "$id" -eq $(($lost_events + 1))

    # Drop [LOST EVENTS] line
    sed -i '1d' $output

Annotation

Implementation Notes