Thread (6 messages) flat view 6 messages, 2 authors, 3d ago

Re: [PATCH net-next 2/4] selftests: net: Lower threshold on debug kernels for big_tcp_tunnels.sh

From: Matthieu Baerts <matttbe@kernel.org>
Date: 2026-08-14 23:07:41
Also in: linux-kselftest

Hi Alice,

On 14/08/2026 21:41, Alice Mikityanska wrote:
From: Alice Mikityanska <redacted>

CONFIG_DEBUG_NET kernels run slower and generate fewer BIG TCP packets,
making the test flaky on upstream CI runners. Lower the default
threshold for those kernels.
Thank you for looking at that!
quoted hunk ↗ jump to hunk
Signed-off-by: Alice Mikityanska <redacted>
---
 tools/testing/selftests/net/big_tcp_tunnels.sh | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/net/big_tcp_tunnels.sh b/tools/testing/selftests/net/big_tcp_tunnels.sh
index 9b7d0456bcc1..e27774eae20e 100755
--- a/tools/testing/selftests/net/big_tcp_tunnels.sh
+++ b/tools/testing/selftests/net/big_tcp_tunnels.sh
@@ -17,11 +17,25 @@ CLIENT_IP6="2001:db8::1:2"
 CLIENT_IP4_TUN="192.168.2.2"
 CLIENT_IP6_TUN="2001:db8::2:2"
 
-: "${PACKETS_THRESHOLD:=1000}"
-
 # Kselftest framework requirement - SKIP code is 4.
 ksft_skip=4
 
+is_debug() {
+	local config="/proc/config.gz"
+	[ -f "$config" ] || config="/boot/config-$(uname -r)"
+	[ -f "$config" ] || return 1 # No config found; assume non-debug.
+	gzip -dcfq "$config" | grep -qx 'CONFIG_DEBUG_NET=y' || return 1
Are you sure it is CONFIG_DEBUG_NET that causes that? It shouldn't be
that heavy.

Do you not want to change the thresholds only for the -dbg runners using
kernel/configs/debug.config? If yes, you should check if
KSFT_MACHINE_SLOW == yes:

https://github.com/linux-netdev/nipa/wiki/How-to-run-netdev-selftests-CI-style#dealing-with-slow-runners-in-performancelatency-tests

Cheers,
Matt
-- 
Sponsored by the NGI0 Core fund.
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