atom: add -f <workers>

atom

@@ -64,6 +64,7 @@ help() {
 	        -c <file>        Load configuration file <file>
 	        -C               Dump configuration and exit
 	        -l <load>        Override max-load
+		-f <workers>     Use exactly <workers> child processes
 	        -T <seconds>     override load-interval
 	        -F <destination> Force re-generation of all files in
 	                         <destination>
@@ -77,7 +78,7 @@ help() {
 
 #parse arguments
 OPTERR=0
-while getopts ':c:Cl:T:F:B:ShDq' opt
+while getopts ':c:Cl:T:F:f:B:ShDq' opt
 do
 	case $opt in
 		c)
@@ -95,6 +96,9 @@ do
 		F)
 			forceall+=("$OPTARG")
 		;;
+		f)
+			fixed_workers="$OPTARG"
+		;;
 		B)
 			maxbatch="$OPTARG"
 		;;
@@ -696,6 +700,10 @@ while (( (remaining || ${#workers[@]}) && ! quit ))
 do
 	read humanload garbage < /proc/loadavg
 	load=${humanload%.*}
+	if (( fixed_workers ))
+	then
+		concurrency="$fixed_workers"
+	else
 	if [ -z "$quit" ]					\
 	&& (( ! pause ))					\
 	&& (( $(date +%s)-concurrencychange >= loadinterval ))
@@ -709,6 +717,7 @@ do
 		then
 			concurrencychange=$(date +%s)
 			(( ++concurrency ))
+			fi
 		fi
 	fi
 	checkworkers