resctl: default to max. priority for table-driven reservations

Table-driven reservations should always have the maximum fixed
priority. Thus default to this behavior, both for convenience and to
avoid accidental misconfiguration.

1 files changed, 8 insertions, 1 deletions

diff --git a/bin/resctl.c b/bin/resctl.c
index f5eda85..712d2e3 100644
--- a/bin/resctl.c
+++ b/bin/resctl.c
@@ -21,7 +21,7 @@ const char *usage_msg =
         "    -p PERIOD         polling reservation period (in ms, default: 100ms)\n"
         "    -d DEADLINE       relative deadline, implicit by default (in ms)\n"
         "    -o OFFSET         offset (also known as phase), zero by default (in ms)\n"
-        "    -q PRIORITY       priority to use (EDF by default, max=0)\n"
+        "    -q PRIORITY       priority to use (EDF by default, highest priority = 1)\n"
         "    -m MAJOR-CYCLE    major cycle length (in ms, for table-driven reservations) \n"
         "\n";
 
@@ -156,6 +156,8 @@ int main(int argc, char** argv)
 
                 case 'q':
                         config.priority = atoi(optarg);
+                        if (!config.priority)
+                                usage("-q: invalid priority");
                         break;
                 case 'c':
                         config.cpu = atoi(optarg);
@@ -182,6 +184,11 @@ int main(int argc, char** argv)
                                 res_type = SPORADIC_POLLING;
                         }  else if (strcmp(optarg, "table-driven") == 0) {
                                 res_type = TABLE_DRIVEN;
+                                /* Default for table-driven reservations to
+                                 * maximum priority. EDF has not meaning for
+                                 * table-driven reservations. */
+                                if (config.priority == LITMUS_NO_PRIORITY)
+                                        config.priority = LITMUS_HIGHEST_PRIORITY;
                         } else {
                                 usage("Unknown reservation type.");
                         }