Hi Naveen,
On Tue, 12 Dec 2023 14:26:07 +0530
Naveen N Rao <naveen@xxxxxxxxxx> wrote:
> Add a test to exercize cpu hotplug with the function tracer active to
> ensure that sensitive functions in idle path are excluded from being
> traced. This helps catch issues such as the one fixed by commit
> 4b3338aaa74d ("powerpc/ftrace: Fix stack teardown in ftrace_no_trace").
>
> Signed-off-by: Naveen N Rao <naveen@xxxxxxxxxx>
> ---
> .../ftrace/test.d/ftrace/func_hotplug.tc | 30 +++++++++++++++++++
> 1 file changed, 30 insertions(+)
> create mode 100644 tools/testing/selftests/ftrace/test.d/ftrace/func_hotplug.tc
>
> diff --git a/tools/testing/selftests/ftrace/test.d/ftrace/func_hotplug.tc b/tools/testing/selftests/ftrace/test.d/ftrace/func_hotplug.tc
> new file mode 100644
> index 000000000000..49731a2b5c23
> --- /dev/null
> +++ b/tools/testing/selftests/ftrace/test.d/ftrace/func_hotplug.tc
> @@ -0,0 +1,30 @@
> +#!/bin/sh
> +# SPDX-License-Identifier: GPL-2.0
> +# description: ftrace - function trace across cpu hotplug
> +# requires: function:tracer
> +
> +if ! which nproc ; then
> + nproc() {
> + ls -d /sys/devices/system/cpu/cpu[0-9]* | wc -l
> + }
> +fi
> +
> +NP=`nproc`
> +
> +if [ $NP -eq 1 ] ;then
> + echo "We can not test cpu hotplug in UP environment"
> + exit_unresolved
> +fi
This looks good, but can you find the 2nd online CPU before
this test?
I mean, there is a case that cpu1 is already offlined and others
like cpu2 is onlined. So we need to use the 2nd online cpu.
Thank you,
> +
> +echo 0 > tracing_on
> +echo > trace
> +: "Set CPU1 offline/online with function tracer enabled"
> +echo function > current_tracer
> +echo 1 > tracing_on
> +(echo 0 > /sys/devices/system/cpu/cpu1/online)
> +(echo "forked"; sleep 1)
> +(echo 1 > /sys/devices/system/cpu/cpu1/online)
> +echo 0 > tracing_on
> +
> +: "Check CPU1 events are recorded"
> +grep -q -e "\[001\]" trace
>
> base-commit: b85ea95d086471afb4ad062012a4d73cd328fa86
> --
> 2.43.0
>
--
Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
