pktgen: Specify the index of first thread

Use "-f <num>", to specify the index of the first
sender thread.
In default first thread is #0.

Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/samples/pktgen/parameters.sh b/samples/pktgen/parameters.sh
index 0361475..3a6244d 100644
--- a/samples/pktgen/parameters.sh
+++ b/samples/pktgen/parameters.sh
@@ -10,6 +10,7 @@
     echo "  -d : (\$DEST_IP)   destination IP"
     echo "  -m : (\$DST_MAC)   destination MAC-addr"
     echo "  -t : (\$THREADS)   threads to start"
+    echo "  -f : (\$F_THREAD)  index of first thread (zero indexed CPU number)"
     echo "  -c : (\$SKB_CLONE) SKB clones send before alloc new SKB"
     echo "  -n : (\$COUNT)     num messages to send per thread, 0 means indefinitely"
     echo "  -b : (\$BURST)     HW level bursting of SKBs"
@@ -21,7 +22,7 @@
 
 ##  --- Parse command line arguments / parameters ---
 ## echo "Commandline options:"
-while getopts "s:i:d:m:t:c:n:b:vxh6" option; do
+while getopts "s:i:d:m:f:t:c:n:b:vxh6" option; do
     case $option in
         i) # interface
           export DEV=$OPTARG
@@ -39,11 +40,13 @@
           export DST_MAC=$OPTARG
 	  info "Destination MAC set to: DST_MAC=$DST_MAC"
           ;;
+        f)
+	  export F_THREAD=$OPTARG
+	  info "Index of first thread (zero indexed CPU number): $F_THREAD"
+          ;;
         t)
 	  export THREADS=$OPTARG
-          export CPU_THREADS=$OPTARG
-	  let "CPU_THREADS -= 1"
-	  info "Number of threads to start: $THREADS (0 to $CPU_THREADS)"
+	  info "Number of threads to start: $THREADS"
           ;;
         c)
 	  export CLONE_SKB=$OPTARG
@@ -82,12 +85,17 @@
     info "Default packet size set to: set to: $PKT_SIZE bytes"
 fi
 
+if [ -z "$F_THREAD" ]; then
+    # First thread (F_THREAD) reference the zero indexed CPU number
+    export F_THREAD=0
+fi
+
 if [ -z "$THREADS" ]; then
-    # Zero CPU threads means one thread, because CPU numbers are zero indexed
-    export CPU_THREADS=0
     export THREADS=1
 fi
 
+export L_THREAD=$(( THREADS + F_THREAD - 1 ))
+
 if [ -z "$DEV" ]; then
     usage
     err 2 "Please specify output device"