Re: [PATCH v3 17/17] selftests/verification: Add selftests for deadline and stall monitors

[Wen Yang <wen.yang@linux.dev>]

On 6/25/26 20:14, Gabriele Monaco wrote:
> Add selftests to verify deadline monitors don't fail under expected
> conditions and the stall monitor report violations only when expected.
> 
> Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
> ---
>   .../verification/test.d/rv_deadline.tc        | 21 ++++++++++++
>   .../selftests/verification/test.d/rv_stall.tc | 33 +++++++++++++++++++
>   2 files changed, 54 insertions(+)
>   create mode 100644 tools/testing/selftests/verification/test.d/rv_deadline.tc
>   create mode 100644 tools/testing/selftests/verification/test.d/rv_stall.tc
> 
> diff --git a/tools/testing/selftests/verification/test.d/rv_deadline.tc b/tools/testing/selftests/verification/test.d/rv_deadline.tc
> new file mode 100644
> index 0000000000..b583096bed
> --- /dev/null
> +++ b/tools/testing/selftests/verification/test.d/rv_deadline.tc
> @@ -0,0 +1,21 @@
> +#!/bin/sh
> +# SPDX-License-Identifier: GPL-2.0-or-later
> +# description: Test deadline monitors trigger no reaction
> +# requires: available_reactors deadline:monitor printk:reactor stress-ng:program
> +
> +load() { # returns true if there was a reaction
> +	local lines_before
> +	lines_before=$(dmesg | wc -l)
> +	stress-ng --cpu 2 --sched deadline --sched-period 100000000 --sched-deadline 100000000 --sched-runtime 20000000 -t 5 &
> +	stress-ng --cpu 2 --sched rr --sched-prio 50 --cyclic 1 --cyclic-policy rr --cyclic-prio 50 -t 5 &
> +	wait
> +	dmesg | tail -n +$((lines_before + 1)) | grep -q "rv: monitor [a-z]\+ does not allow event"
> +}
> +
> +echo 1 > monitors/deadline/enable
> +echo printk > monitors/deadline/reactors
> +
> +! load || false
> +
> +echo nop > monitors/deadline/reactors
> +echo 0 > monitors/deadline/enable
> diff --git a/tools/testing/selftests/verification/test.d/rv_stall.tc b/tools/testing/selftests/verification/test.d/rv_stall.tc
> new file mode 100644
> index 0000000000..8e9bcbb441
> --- /dev/null
> +++ b/tools/testing/selftests/verification/test.d/rv_stall.tc
> @@ -0,0 +1,33 @@
> +#!/bin/sh
> +# SPDX-License-Identifier: GPL-2.0-or-later
> +# description: Test stall monitor
> +# requires: available_reactors stall:monitor printk:reactor stress-ng:program
> +
> +THRESHOLD=/sys/module/stall/parameters/threshold_jiffies
> +
> +load() { # returns true if there was a reaction
> +	local lines_before cpu
> +	cpu=$(($(nproc) - 1))
> +	lines_before=$(dmesg | wc -l)
> +	stress-ng --cpu 1 --taskset "$cpu" --sched rr --sched-prio 1 -t 3 &
> +	stress-ng --cpu 5 --taskset "$cpu" -t 3 &
> +	wait
> +	dmesg | tail -n +$((lines_before + 1)) | grep -q "rv: monitor stall does not allow event"
> +}
> +
> +echo 5000 > $THRESHOLD
> +echo 1 > monitors/stall/enable
> +echo printk > monitors/stall/reactors
> +
> +! load || false
> +
> +echo 0 > monitors/stall/enable
> +echo 70 > $THRESHOLD
> +echo 1 > monitors/stall/enable
> +
> +load
> +
> +echo nop > monitors/stall/reactors
> +echo 0 > monitors/stall/enable
> +
> +echo 1000 > $THRESHOLD

A little worried:
If the system had a different value configured before the test ran,
this silently changes system state for anything running after it.


--
Best wishes,
Wen