[PATCH] test/perf: Select a single IPv6 namespace address in pasta tests

[Stefano Brivio <sbrivio@redhat.com>]

By dropping the filter on prefix length, commit 910f4f910301
("test: Don't require 64-bit prefixes in perf tests") broke tests on
setups where two global unicast IPv6 addresses are available, which
is the typical case when the "host" is a VM running under passt with
addresses from SLAAC and DHCPv6, because two addresses will be
returned.

Pick the first one instead. We don't really care about the prefix
length, any of these addresses will work.

Fixes: 910f4f910301 ("test: Don't require 64-bit prefixes in perf tests")
Link: https://archives.passt.top/passt-dev/20241119214344.6b4a5b3a@elisabeth/
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
---
 test/perf/pasta_tcp | 2 +-
 test/perf/pasta_udp | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/test/perf/pasta_tcp b/test/perf/pasta_tcp
index 88284b2..bc0de3c 100644
--- a/test/perf/pasta_tcp
+++ b/test/perf/pasta_tcp
@@ -211,7 +211,7 @@ tr	TCP throughput over IPv6: host to ns
 iperf3s	ns 10002
 
 nsout	IFNAME ip -j link show | jq -rM '.[] | select(.link_type == "ether").ifname'
-nsout	ADDR6 ip -j -6 addr show|jq -rM '.[] | select(.ifname == "__IFNAME__").addr_info[] | select(.scope == "global").local'
+nsout	ADDR6 ip -j -6 addr show|jq -rM '[.[] | select(.ifname == "__IFNAME__").addr_info[] | select(.scope == "global").local] | .[0]'
 bw	-
 bw	-
 bw	-
diff --git a/test/perf/pasta_udp b/test/perf/pasta_udp
index 3d07091..ab2f3e8 100644
--- a/test/perf/pasta_udp
+++ b/test/perf/pasta_udp
@@ -196,7 +196,7 @@ tr	UDP throughput over IPv6: host to ns
 iperf3s	ns 10002
 
 nsout	IFNAME ip -j link show | jq -rM '.[] | select(.link_type == "ether").ifname'
-nsout	ADDR6 ip -j -6 addr show|jq -rM '.[] | select(.ifname == "__IFNAME__").addr_info[] | select(.scope == "global").local'
+nsout	ADDR6 ip -j -6 addr show|jq -rM '[.[] | select(.ifname == "__IFNAME__").addr_info[] | select(.scope == "global").local] | .[0]'
 iperf3	BW host __ADDR6__ 10002 __TIME__ __OPTS__ -b 8G -l 1472
 bw	__BW__ 0.3 0.5
 iperf3	BW host __ADDR6__ 10002 __TIME__ __OPTS__ -b 12G -l 3972
-- 
@@ -196,7 +196,7 @@ tr	UDP throughput over IPv6: host to ns
 iperf3s	ns 10002
 
 nsout	IFNAME ip -j link show | jq -rM '.[] | select(.link_type == "ether").ifname'
-nsout	ADDR6 ip -j -6 addr show|jq -rM '.[] | select(.ifname == "__IFNAME__").addr_info[] | select(.scope == "global").local'
+nsout	ADDR6 ip -j -6 addr show|jq -rM '[.[] | select(.ifname == "__IFNAME__").addr_info[] | select(.scope == "global").local] | .[0]'
 iperf3	BW host __ADDR6__ 10002 __TIME__ __OPTS__ -b 8G -l 1472
 bw	__BW__ 0.3 0.5
 iperf3	BW host __ADDR6__ 10002 __TIME__ __OPTS__ -b 12G -l 3972
-- 
2.43.0