selftests: forwarding: Increase maximum deviation in multipath test

We sometimes observe failures in the test due to too large discrepancy
between the measured and expected ratios. For example:

TEST: ECMP                                                          [FAIL]
        Too large discrepancy between expected and measured ratios
        INFO: Expected ratio 1.00 Measured ratio 1.11

Fix this by allowing an up to 15% deviation between both ratios.

Another possibility is to increase the number of generated flows, but
this will prolong the execution time of the test, which is already quite
high.
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tools/testing/selftests/net/forwarding/router_multipath.sh

@@ -191,7 +191,7 @@ multipath_eval()
        diff=$(echo $weights_ratio - $packets_ratio | bc -l)
        diff=${diff#-}
 
-       test "$(echo "$diff / $weights_ratio > 0.1" | bc -l)" -eq 0
+       test "$(echo "$diff / $weights_ratio > 0.15" | bc -l)" -eq 0
        check_err $? "Too large discrepancy between expected and measured ratios"
        log_test "$desc"
        log_info "Expected ratio $weights_ratio Measured ratio $packets_ratio"