Re: [PATCH 5/6] rtla/tests: Reset osnoise options before check

[John Kacur <jkacur@redhat.com>]

On Thu, 20 Mar 2025, Tomas Glozar wrote:

> Remove any dangling tracing instances from previous improperly exited
> runs of rtla, and reset osnoise options to default before running a test
> case.
> 
> This ensures that the test results are deterministic. Specific test
> cases checked that rtla behaves correctly even when the tracer state is
> not clean will be added later.
> 
> Signed-off-by: Tomas Glozar <tglozar@redhat.com>
> ---
>  tools/tracing/rtla/tests/engine.sh | 40 ++++++++++++++++++++++++++++++
>  1 file changed, 40 insertions(+)
> 
> diff --git a/tools/tracing/rtla/tests/engine.sh b/tools/tracing/rtla/tests/engine.sh
> index 64d0446dc28e..5db8aa4bc031 100644
> --- a/tools/tracing/rtla/tests/engine.sh
> +++ b/tools/tracing/rtla/tests/engine.sh
> @@ -8,12 +8,44 @@ test_begin() {
>  	[ -n "$TEST_COUNT" ] && echo "1..$TEST_COUNT"
>  }
>  
> +reset_osnoise() {
> +	# Reset osnoise options to default and remove any dangling instances created
> +	# by improperly exited rtla runs.
> +	pushd /sys/kernel/tracing || return 1
> +
> +	# Remove dangling instances created by previous rtla run
> +	echo 0 > tracing_thresh
> +	cd instances
> +	for i in osnoise_top osnoise_hist timerlat_top timerlat_hist
> +	do
> +		[ ! -d "$i" ] && continue
> +		rmdir "$i"
> +	done
> +
> +	# Reset options to default
> +	# Note: those are copied from the default values of osnoise_data
> +	# in kernel/trace/trace_osnoise.c
> +	cd ../osnoise
> +	echo all > cpus
> +	echo DEFAULTS > options
> +	echo 1000000 > period_us
> +	echo 0 > print_stack
> +	echo 1000000 > runtime_us
> +	echo 0 > stop_tracing_total_us
> +	echo 0 > stop_tracing_us
> +	echo 1000 > timerlat_period_us
> +
> +	popd
> +}
> +
>  check() {
>  	# Simple check: run rtla with given arguments and test exit code.
>  	# If TEST_COUNT is set, run the test. Otherwise, just count.
>  	ctr=$(($ctr + 1))
>  	if [ -n "$TEST_COUNT" ]
>  	then
> +		# Reset osnoise options before running test.
> +		[ "$NO_RESET_OSNOISE" == 1 ] || reset_osnoise
>  		# Run rtla; in case of failure, include its output as comment
>  		# in the test results.
>  		result=$(stdbuf -oL $TIMEOUT "$RTLA" $2 2>&1); exitcode=$?
> @@ -37,6 +69,14 @@ unset_timeout() {
>  	unset TIMEOUT
>  }
>  
> +set_no_reset_osnoise() {
> +	NO_RESET_OSNOISE=1
> +}
> +
> +unset_no_reset_osnoise() {
> +	unset NO_RESET_OSNOISE
> +}
> +
>  test_end() {
>  	# If running without TEST_COUNT, tests are not actually run, just
>  	# counted. In that case, re-run the test with the correct count.
> -- 
> 2.48.1
> 
> 
> 
Reviewed by: John Kacur <jkacur@redhat.com>