[LTP] [PATCH v2 1/1] net: tst_netload_compare(): Ignore performance failures

[Petr Vorel]

Performance failures in tests which use tst_netload_compare() (tests in
runtest/net.features) can hide a real error (e.g. test fails due missing
required kernel module). Best solution would be to have feature tests
(likely written in C API) and performance tests (the current ones).

But until it happens, allow to ignore performance failure with
environment variable LTP_NET_FEATURES_IGNORE_PERFORMANCE_FAILURE=1.

Signed-off-by: Petr Vorel <pvorel@suse.cz>
---
changes v1->v2:
* Ignoring performance requires setting LTP_NET_FEATURES_IGNORE_PERFORMANCE_FAILURE=1
(previously it was ignored by default, Martin), therefore rename the variable.
* Variable uses LTP_ prefix (user defined), thus no need to whitelist it
in tst_net.sh.

Martin also pointed out that message can be printed multiple times, but I
don't think this is a problem (it's better that tester sees it).

 testcases/lib/tst_net.sh    | 19 +++++++++++++++----
 testcases/network/README.md |  4 ++++
 2 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/testcases/lib/tst_net.sh b/testcases/lib/tst_net.sh
index 2ed0e787f..6cf7f2fcb 100644
--- a/testcases/lib/tst_net.sh
+++ b/testcases/lib/tst_net.sh
@@ -1,7 +1,7 @@
 #!/bin/sh
 # SPDX-License-Identifier: GPL-2.0-or-later
 # Copyright (c) 2014-2017 Oracle and/or its affiliates. All Rights Reserved.
-# Copyright (c) 2016-2023 Petr Vorel <pvorel@suse.cz>
+# Copyright (c) 2016-2024 Petr Vorel <pvorel@suse.cz>
 # Author: Alexey Kodanev <alexey.kodanev@oracle.com>
 
 [ -n "$TST_LIB_NET_LOADED" ] && return 0
@@ -863,22 +863,33 @@ tst_netload()
 # TIME: time that is compared to the base one
 # THRESHOD_LOW: lower limit for TFAIL
 # THRESHOD_HIGH: upper limit for TWARN
+#
+# Slow performance can be ignored with setting environment variable
+# LTP_NET_FEATURES_IGNORE_PERFORMANCE_FAILURE=1
 tst_netload_compare()
 {
 	local base_time=$1
 	local new_time=$2
 	local threshold_low=$3
 	local threshold_hi=$4
+	local ttype='TFAIL'
+	local msg res
 
 	if [ -z "$base_time" -o -z "$new_time" -o -z "$threshold_low" ]; then
 		tst_brk_ TBROK "tst_netload_compare: invalid argument(s)"
 	fi
 
-	local res=$(((base_time - new_time) * 100 / base_time))
-	local msg="performance result is ${res}%"
+	res=$(((base_time - new_time) * 100 / base_time))
+	msg="performance result is ${res}%"
 
 	if [ "$res" -lt "$threshold_low" ]; then
-		tst_res_ TFAIL "$msg < threshold ${threshold_low}%"
+		if [ "$LTP_NET_FEATURES_IGNORE_PERFORMANCE_FAILURE" = 1 ]; then
+			ttype='TINFO';
+			tst_res_ TINFO "WARNING: slow performance is not treated as error due LTP_NET_FEATURES_IGNORE_PERFORMANCE_FAILURE=1"
+		else
+			tst_res_ TINFO "Following slow performance can be ignored with LTP_NET_FEATURES_IGNORE_PERFORMANCE_FAILURE=1"
+		fi
+		tst_res_ $ttype "$msg < threshold ${threshold_low}%"
 		return
 	fi
 
diff --git a/testcases/network/README.md b/testcases/network/README.md
index a0a1d3d95..e1b1296d6 100644
--- a/testcases/network/README.md
+++ b/testcases/network/README.md
@@ -84,6 +84,10 @@ Where
 Default values for all LTP network parameters are set in `testcases/lib/tst_net.sh`.
 Network stress parameters are documented in `testcases/network/stress/README`.
 
+Tests which use `tst_netload_compare()` test also performance. They can fail on
+overloaded SUT.  To ignore performance failure and test only the network functionality,
+set `LTP_NET_FEATURES_IGNORE_PERFORMANCE_FAILURE=1` environment variable.
+
 ## Debugging
 Both single and two host configurations support debugging via
 `TST_NET_RHOST_RUN_DEBUG=1` environment variable.
-- 
2.43.0