selftests: net/forwarding: spawn sh inside vrf to speed up ping loop

Looking at timestamped output of netdev CI reveals that
most of the time in forwarding tests for custom route
hashing is spent on a single case, namely the test which
uses ping (mausezahn does not support flow labels).

On a non-debug kernel we spend 714 of 730 total test
runtime (97%) on this test case. While having flow label
support in a traffic gen tool / mausezahn would be best,
we can significantly speed up the loop by putting ip vrf exec
outside of the iteration.

In a test of 1000 pings using a normal loop takes 50 seconds
to finish. While using:

  ip vrf exec $vrf sh -c "$loop-body"

takes 12 seconds (1/4 of the time).

Some of the slowness is likely due to our inefficient virtualization
setup, but even on my laptop running "ip link help" 16k times takes
25-30 seconds, so I think it's worth optimizing even for fastest
setups.

Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Tested-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Hangbin Liu <liuhangbin@gmail.com>
Link: https://patch.msgid.link/20240817203659.712085-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/tools/testing/selftests/net/forwarding/custom_multipath_hash.sh b/tools/testing/selftests/net/forwarding/custom_multipath_hash.sh
index 1783c10215e5ce3e9912404bc31e9e959627d767..7d531f7091e6f4a6f7a726f662d40ba8886711e0 100755 (executable)
--- a/tools/testing/selftests/net/forwarding/custom_multipath_hash.sh
+++ b/tools/testing/selftests/net/forwarding/custom_multipath_hash.sh
@@ -224,10 +224,10 @@ send_dst_ipv6()
 send_flowlabel()
 {
        # Generate 16384 echo requests, each with a random flow label.
-       for _ in $(seq 1 16384); do
-               ip vrf exec v$h1 \
-                       $PING6 2001:db8:4::2 -F 0 -c 1 -q >/dev/null 2>&1
-       done
+       ip vrf exec v$h1 sh -c \
+               "for _ in {1..16384}; do \
+                       $PING6 2001:db8:4::2 -F 0 -c 1 -q >/dev/null 2>&1; \
+               done"
 }
 
 send_src_udp6()

diff --git a/tools/testing/selftests/net/forwarding/gre_custom_multipath_hash.sh b/tools/testing/selftests/net/forwarding/gre_custom_multipath_hash.sh
index 9788bd0f6e8b37d70d12d3447461d756b76b227b..dda11a4a9450a8450abb73e2bbabf735f48434dc 100755 (executable)
--- a/tools/testing/selftests/net/forwarding/gre_custom_multipath_hash.sh
+++ b/tools/testing/selftests/net/forwarding/gre_custom_multipath_hash.sh
@@ -319,10 +319,10 @@ send_dst_ipv6()
 send_flowlabel()
 {
        # Generate 16384 echo requests, each with a random flow label.
-       for _ in $(seq 1 16384); do
-               ip vrf exec v$h1 \
-                       $PING6 2001:db8:2::2 -F 0 -c 1 -q >/dev/null 2>&1
-       done
+       ip vrf exec v$h1 sh -c \
+               "for _ in {1..16384}; do \
+                       $PING6 2001:db8:2::2 -F 0 -c 1 -q >/dev/null 2>&1; \
+               done"
 }
 
 send_src_udp6()

diff --git a/tools/testing/selftests/net/forwarding/ip6gre_custom_multipath_hash.sh b/tools/testing/selftests/net/forwarding/ip6gre_custom_multipath_hash.sh
index 2ab9eaaa5532ae1aeb4284ba541b7b2ed6c2495f..e28b4a079e5250a44a70486932304a67ae6269dc 100755 (executable)
--- a/tools/testing/selftests/net/forwarding/ip6gre_custom_multipath_hash.sh
+++ b/tools/testing/selftests/net/forwarding/ip6gre_custom_multipath_hash.sh
@@ -321,10 +321,10 @@ send_dst_ipv6()
 send_flowlabel()
 {
        # Generate 16384 echo requests, each with a random flow label.
-       for _ in $(seq 1 16384); do
-               ip vrf exec v$h1 \
-                       $PING6 2001:db8:2::2 -F 0 -c 1 -q >/dev/null 2>&1
-       done
+       ip vrf exec v$h1 sh -c \
+               "for _ in {1..16384}; do \
+                       $PING6 2001:db8:2::2 -F 0 -c 1 -q >/dev/null 2>&1; \
+               done"
 }
 
 send_src_udp6()