devtools: fix null test for NUMA systems

On NUMA systems, default cores (0 and 1) might be on different memory
nodes. Double the amount of memory.

Fixes: 9e6b36c ("app/testpmd: reduce memory consumption")
Cc: stable@dpdk.org

Signed-off-by: David Marchand <david.marchand@redhat.com>

devtools/test-null.sh

@@ -27,6 +27,7 @@ else
 fi
 
 (sleep 1 && echo stop) |
-$testpmd -c $coremask --no-huge -m 20 \
+# testpmd only needs 20M, make it x2 (default number of cores) for NUMA systems
+$testpmd -c $coremask --no-huge -m 40 \
 	$libs -a 0:0.0 --vdev net_null1 --vdev net_null2 $eal_options -- \
 	--no-mlockall --total-num-mbufs=2048 $testpmd_options -ia