metrics: Improvement to the description of certain functions.

This PR rephrased the description and usage of certain functions
as such as:
- set_kata_configuration_performance
- set_kata_config_file
- get_current_kata_config_file
- check_if_root
- check_ctr_images

Signed-off-by: David Esparza <david.esparza.borquez@intel.com>

tests/metrics/lib/common.bash

@@ -128,8 +128,9 @@ function build_dockerfile_image()
 		|| die "Failed to docker build image $image"
 }
 
-# This function removes the ctr image, builds a new one using a dockerfile
-# and imports the image from docker to ctr
+# This function deletes any existing ctr image passed as a parameter,
+# then creates a new image using a dockerfile, and finally exports
+# a new version of the docker image to ctr.
 function check_ctr_images()
 {
 	local ctr_image="$1"
@@ -437,11 +438,11 @@ function check_containers_are_running() {
 	fi
 }
 
-# This function receives an identifier used to name a performance Kata configuration file.
-# The current kata configuration is copied to a new kata config file with the difference
-# that the parameters 'default_vcpus' and 'default_memory' will be updated with the values
-# of the max vcpus and the available memory in the system.
-# Finally it makes Kata point to the new configuration file.
+# This function generates a new kata configuration file based on the current configuration file,
+# with the update of two parameters: 'default_vcpus' and 'default_memory'.
+# These parameters are updated so that they point to the maximum number of vcpus available
+# on the system and to use all the available memory on the system.
+# Finally, a link to the new configuration file is created for kata to use in creating containers.
 set_kata_configuration_performance() {
 	WORKLOAD_CONFIG_FILE="${1}"
 
@@ -476,8 +477,8 @@ function clean_cache() {
         sudo sync; echo 1 > /proc/sys/vm/drop_caches
 }
 
-# This function receives as single parameter, the name of a valid Kata configuration file
-# which will be established as the default Kata configuration to start new Kata containers.
+# This function receives as a single parameter the path to a valid kata configuration file
+# that will be set as the configuration used to start new Kata containers.
 function set_kata_config_file() {
 	NEW_KATA_CONFIG=${1}
 
@@ -495,6 +496,8 @@ function set_kata_config_file() {
         popd > /dev/null
 }
 
+# This function returns the path to the symbolic link pointed to by the kata
+# configuration file: configuration.toml.
 function get_current_kata_config_file() {
 	declare -n current_config_file=$1
 
@@ -505,6 +508,8 @@ function get_current_kata_config_file() {
 	current_config_file="${KATA_CONFIG_FNAME}"
 }
 
+# This function checks if the current session is runnin as root, 
+# if that is not the case, the function exits with an error message.
 function check_if_root() {
 	[ "$EUID" -ne 0 ] && die "Please run as root or use sudo."
 }