torture: Provide more sensible nreader/nwriter defaults for rcuperf

The default values for nreader and nwriter are apparently not all that
user-friendly, resulting in people doing scalability tests that ran all
runs at large scale.  This commit therefore makes both the nreaders and
nwriters module default to the number of CPUs, and adds a comment to
rcuperf.c stating that the number of CPUs should be specified using the
nr_cpus kernel boot parameter.  This commit also eliminates the redundant
rcuperf scripting specification of default values for these parameters.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

tools/testing/selftests/rcutorture/configs/rcuperf/ver_functions.sh

@@ -20,32 +20,10 @@
 #
 # Authors: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
 
-# rcuperf_param_nreaders bootparam-string
-#
-# Adds nreaders rcuperf module parameter if not already specified.
-rcuperf_param_nreaders () {
-	if ! echo "$1" | grep -q "rcuperf.nreaders"
-	then
-		echo rcuperf.nreaders=-1
-	fi
-}
-
-# rcuperf_param_nwriters bootparam-string
-#
-# Adds nwriters rcuperf module parameter if not already specified.
-rcuperf_param_nwriters () {
-	if ! echo "$1" | grep -q "rcuperf.nwriters"
-	then
-		echo rcuperf.nwriters=-1
-	fi
-}
-
 # per_version_boot_params bootparam-string config-file seconds
 #
 # Adds per-version torture-module parameters to kernels supporting them.
 per_version_boot_params () {
-	echo $1 `rcuperf_param_nreaders "$1"` \
-		`rcuperf_param_nwriters "$1"` \
-		rcuperf.shutdown=1 \
+	echo $1 rcuperf.shutdown=1 \
 		rcuperf.verbose=1
 }