[PATCH mptcp-net 0/2] selftests: mptcp: lib: get MIB counters for the right test

[PATCH mptcp-net 0/2] selftests: mptcp: lib: get MIB counters for the right test

[Matthieu Baerts (NGI0)]

In case of errors, mptcp_lib_pr_nstat is called to dump the nstat
counters, but for some tests, it was dumping the counters for all
subtests, not just the current one.

That's an issue for tests that don't recreate the netns for each
subtest, e.g. mptcp_connect.sh. In this case, 'nstat -a' will look at
the absolute counters since the creation of the netns, making
debugging harder.

Instead, it should dump the counters for the current test, by using the
history recorded in /tmp/<ns>.nstat, if available, and not using '-a'
which was dumping the absolute values instead of calculating increments.

While at it, rename the previous 'hist' variable to 'cache' as it was
used to look at the cache, not the nstat history.

Do the same in mptcp_lib_get_counter, even if it wasn't an issue for
the moment. Still, good to fix it for future usage, and to align it
with the rest.

Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
Matthieu Baerts (NGI0) (2):
      selftests: mptcp: lib: dump nstat for the right test
      selftests: mptcp: lib: get counters for the right test

 tools/testing/selftests/net/mptcp/mptcp_lib.sh | 26 +++++++++++++++-----------
 1 file changed, 15 insertions(+), 11 deletions(-)
---
base-commit: ab76ed72e0bed8352d3b8e2b4d1be7c823e5fba3
change-id: 20260813-sft-mptcp-nstat-hist-33411708430f

Best regards,
--  
Matthieu Baerts (NGI0) <matttbe@kernel.org>

[PATCH mptcp-net 1/2] selftests: mptcp: lib: dump nstat for the right test

[Matthieu Baerts (NGI0)]

In case of errors, mptcp_lib_pr_nstat is called to dump the nstat
counters, but for some tests, it was dumping the counters for all
subtests, not just the current one.

That's an issue for tests that don't recreate the netns for each
subtest, e.g. mptcp_connect.sh. In this case, 'nstat -a' will look at
the absolute counters since the creation of the netns, making
debugging harder.

Instead, it should dump the counters for the current test, by using the
history recorded in /tmp/<ns>.nstat if available, and not using '-a'
which was dumping the absolute values instead of calculating increments.

While at it, rename the previous 'hist' variable to 'cache' as it was
used to look at the cache, not the nstat history.

Fixes: 658e53141780 ("selftests: mptcp: join: dump stats from history")
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
 tools/testing/selftests/net/mptcp/mptcp_lib.sh | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/net/mptcp/mptcp_lib.sh b/tools/testing/selftests/net/mptcp/mptcp_lib.sh
index 5ef6033775c8..da1da414c30f 100644
--- a/tools/testing/selftests/net/mptcp/mptcp_lib.sh
+++ b/tools/testing/selftests/net/mptcp/mptcp_lib.sh
@@ -108,12 +108,14 @@ mptcp_lib_pr_info() {
 
 mptcp_lib_pr_nstat() {
 	local ns="${1}"
-	local hist="/tmp/${ns}.out"
+	local cache="/tmp/${ns}.out"
+	local hist="/tmp/${ns}.nstat"
 
-	if [ -f "${hist}" ]; then
-		awk '$2 != 0 { print "  "$0 }' "${hist}"
+	if [ -f "${cache}" ]; then
+		awk '$2 != 0 { print "  "$0 }' "${cache}"
 	else
-		ip netns exec "${ns}" nstat -as | grep Tcp
+		NSTAT_HISTORY="${hist}" ip netns exec "${ns}" nstat -s |
+			grep Tcp
 	fi
 }
 

-- 
2.53.0

[PATCH mptcp-net 2/2] selftests: mptcp: lib: get counters for the right test

[Matthieu Baerts (NGI0)]

When the value for a MIB counter is required, mptcp_lib_get_counter is
called. It tries to use the cache, if available. If not it falls back to
calling 'nstat' directly by looking at the absolute counters.

That's an issue for tests that don't recreate the netns for each
subtest. In this case, 'nstat -a' will look at the counters for the
netns.

Instead, it should look at the increment for the current test, by using
the history recorded in /tmp/<ns>.nstat, if available, and not using
'-a' which was dumping the absolute values.

While at it, rename the previous 'hist' variable to 'cache' as it was
used to look at the cache, not the nstat history.

Fixes: 71388a9f331d ("selftests: mptcp: lib: get counters from nstat history")
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
 tools/testing/selftests/net/mptcp/mptcp_lib.sh | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/tools/testing/selftests/net/mptcp/mptcp_lib.sh b/tools/testing/selftests/net/mptcp/mptcp_lib.sh
index da1da414c30f..b9d14647f401 100644
--- a/tools/testing/selftests/net/mptcp/mptcp_lib.sh
+++ b/tools/testing/selftests/net/mptcp/mptcp_lib.sh
@@ -416,19 +416,21 @@ mptcp_lib_nstat_get() {
 }
 
 # $1: ns, $2: MIB counter
-# Get the counter from the history (mptcp_lib_nstat_{init,get}()) if available.
-# If not, get the counter from nstat ignoring any history.
+# Get the counter from the cache (mptcp_lib_nstat_{init,get}()) if available.
+# If not, get the counter from nstat ignoring any cache, but using the history.
 mptcp_lib_get_counter() {
 	local ns="${1}"
 	local counter="${2}"
-	local hist="/tmp/${ns}.out"
+	local cache="/tmp/${ns}.out"
+	local hist="/tmp/${ns}.nstat"
 	local count
 
-	if [[ -s "${hist}" && "${counter}" == *"Tcp"* ]]; then
-		count=$(awk "/^${counter} / {print \$2; exit}" "${hist}")
+	if [[ -s "${cache}" && "${counter}" == *"Tcp"* ]]; then
+		count=$(awk "/^${counter} / {print \$2; exit}" "${cache}")
 	else
-		count=$(ip netns exec "${ns}" nstat -asz "${counter}" |
-			awk 'NR==1 {next} {print $2}')
+		count=$(NSTAT_HISTORY="${hist}" ip netns exec "${ns}" \
+			nstat -sz "${counter}" |
+				awk 'NR==1 {next} {print $2}')
 	fi
 	if [ -z "${count}" ]; then
 		mptcp_lib_fail_if_expected_feature "${counter} counter"

-- 
2.53.0

Re: [PATCH mptcp-net 0/2] selftests: mptcp: lib: get MIB counters for the right test

[MPTCP CI]

Hi Matthieu,

Thank you for your modifications, that's great!

Our CI did some validations and here is its report:

- KVM Validation: normal (except selftest_mptcp_join): Success! ✅
- KVM Validation: normal (only selftest_mptcp_join): Success! ✅
- KVM Validation: debug (except selftest_mptcp_join): Success! ✅
- KVM Validation: debug (only selftest_mptcp_join): Success! ✅
- KVM Validation: btf-normal (only bpftest_all): Success! ✅
- KVM Validation: btf-debug (only bpftest_all): Success! ✅
- Task: https://github.com/multipath-tcp/mptcp_net-next/actions/runs/31693194883

Initiator: Patchew Applier
Commits: https://github.com/multipath-tcp/mptcp_net-next/commits/1737d20f1a46
Patchwork: https://patchwork.kernel.org/project/mptcp/list/?series=1145356


If there are some issues, you can reproduce them using the same environment as
the one used by the CI thanks to a docker image, e.g.:

    $ cd [kernel source code]
    $ docker run -v "${PWD}:${PWD}:rw" -w "${PWD}" --privileged --rm -it \
        --pull always mptcp/mptcp-upstream-virtme-docker:latest \
        auto-normal

For more details:

    https://github.com/multipath-tcp/mptcp-upstream-virtme-docker


Please note that despite all the efforts that have been already done to have a
stable tests suite when executed on a public CI like here, it is possible some
reported issues are not due to your modifications. Still, do not hesitate to
help us improve that ;-)

Cheers,
MPTCP GH Action bot
Bot operated by Matthieu Baerts (NGI0 Core)