diff mbox series

kselftest: dt: Stop relying on dirname to improve performance

Message ID 20231208133955.483851-1-nfraprado@collabora.com (mailing list archive)
State Accepted
Commit 6154fb9c2134f8d9534b2de10491aa3a22f3c9ff
Headers show
Series kselftest: dt: Stop relying on dirname to improve performance | expand

Commit Message

Nícolas F. R. A. Prado Dec. 8, 2023, 1:39 p.m. UTC
When walking directory trees, instead of looking for specific files and
running dirname to get the parent folder, traverse all folders and
ignore the ones not containing the desired files. This avoids the need
to call dirname inside the loop, which gives a big performance boost,
approximately halving run time: Running locally on a
mt8192-asurada-spherion, which reports 160 test cases, has gone from
5.5s to 2.9s, while running remotely with an nfsroot has gone from
13.5s to 5.5s.

This change has a side-effect, which is that the root DT node now
also shows in the output, even though it isn't expected to bind to a
driver. However there shouldn't be a matching driver for the board
compatible, so the end result will be just an extra skipped test:

ok 1 / # SKIP

Reported-by: Mark Brown <broonie@kernel.org>
Closes: https://lore.kernel.org/all/310391e8-fdf2-4c2f-a680-7744eb685177@sirena.org.uk
Fixes: 14571ab1ad21 ("kselftest: Add new test for detecting unprobed Devicetree devices")
Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>

---

 tools/testing/selftests/dt/test_unprobed_devices.sh | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

Comments

Mark Brown Dec. 8, 2023, 5:29 p.m. UTC | #1
On Fri, Dec 08, 2023 at 10:39:27AM -0300, Nícolas F. R. A. Prado wrote:
> When walking directory trees, instead of looking for specific files and
> running dirname to get the parent folder, traverse all folders and
> ignore the ones not containing the desired files. This avoids the need
> to call dirname inside the loop, which gives a big performance boost,
> approximately halving run time: Running locally on a
> mt8192-asurada-spherion, which reports 160 test cases, has gone from
> 5.5s to 2.9s, while running remotely with an nfsroot has gone from
> 13.5s to 5.5s.

It's hard to be sure exactly since the runtime is a bit variable but it
does look like this is running substantially faster on the test systems
I have that were most affected by the slowdown, looks like approximately
a quarter of the time, and all the tests that were present before seem
to still be present.

Tested-by: Mark Brown <broonie@kernel.org>
diff mbox series

Patch

diff --git a/tools/testing/selftests/dt/test_unprobed_devices.sh b/tools/testing/selftests/dt/test_unprobed_devices.sh
index b07af2a4c4de..7fae90293a9d 100755
--- a/tools/testing/selftests/dt/test_unprobed_devices.sh
+++ b/tools/testing/selftests/dt/test_unprobed_devices.sh
@@ -33,8 +33,8 @@  if [[ ! -d "${PDT}" ]]; then
 fi
 
 nodes_compatible=$(
-	for node_compat in $(find ${PDT} -name compatible); do
-		node=$(dirname "${node_compat}")
+	for node in $(find ${PDT} -type d); do
+		[ ! -f "${node}"/compatible ] && continue
 		# Check if node is available
 		if [[ -e "${node}"/status ]]; then
 			status=$(tr -d '\000' < "${node}"/status)
@@ -46,10 +46,11 @@  nodes_compatible=$(
 
 nodes_dev_bound=$(
 	IFS=$'\n'
-	for uevent in $(find /sys/devices -name uevent); do
-		if [[ -d "$(dirname "${uevent}")"/driver ]]; then
-			grep '^OF_FULLNAME=' "${uevent}" | sed -e 's|OF_FULLNAME=||'
-		fi
+	for dev_dir in $(find /sys/devices -type d); do
+		[ ! -f "${dev_dir}"/uevent ] && continue
+		[ ! -d "${dev_dir}"/driver ] && continue
+
+		grep '^OF_FULLNAME=' "${dev_dir}"/uevent | sed -e 's|OF_FULLNAME=||'
 	done
 	)