Add -u (underrun) to rtspin

When debugging slack rules, it's useful to induce random underruns.

Note: this is a debug feature and not intended for benchmarking.

1 files changed, 20 insertions, 3 deletions

diff --git a/bin/rtspin.c b/bin/rtspin.c
index 44073cc..31962ec 100644
--- a/bin/rtspin.c
+++ b/bin/rtspin.c
@@ -185,13 +185,13 @@ static int job(double exec_time, double program_end, int lock_od, double cs_leng
         }
 }
 
-#define OPTSTR "p:c:wlveo:f:s:q:r:X:L:Q:viR"
+#define OPTSTR "p:c:wlveo:f:s:q:r:X:L:Q:viRu:"
 int main(int argc, char** argv)
 {
         int ret;
         lt_t wcet;
         lt_t period;
-        double wcet_ms, period_ms;
+        double wcet_ms, period_ms, underrun_ms = 0;
         unsigned int priority = LITMUS_NO_PRIORITY;
         int migrate = 0;
         int cluster = 0;
@@ -266,6 +266,11 @@ int main(int argc, char** argv)
                 case 's':
                         scale = atof(optarg);
                         break;
+                case 'u':
+                        underrun_ms = atof(optarg);
+                        if (underrun_ms <= 0)
+                                usage("-u: positive argument needed.");
+                        break;
                 case 'X':
                         protocol = lock_protocol_for_name(optarg);
                         if (protocol < 0)
@@ -380,6 +385,9 @@ int main(int argc, char** argv)
                         bail_out("failed to create reservation");
         }
 
+        srand48(time(NULL));
+
+
         init_litmus();
 
         start = wctime();
@@ -415,6 +423,7 @@ int main(int argc, char** argv)
                             lock_od, cs_length * 0.001);
                 }
         } else {
+                double acet;
                 do {
                         if (verbose) {
                                 get_job_no(&job_no);
@@ -439,7 +448,15 @@ int main(int argc, char** argv)
                                 }
                         }
                         /* convert to seconds and scale */
-                } while (job(wcet_ms * 0.001 * scale, start + duration,
+                        acet = (wcet_ms - drand48() * underrun_ms) * 0.001;
+                        if (acet < 0)
+                                acet = 0;
+                        acet *= scale;
+                        if (verbose)
+                                printf("\ttarget ACET: %6.2fms (%.2f%% of WCET)\n",
+                                        acet * 1000,
+                                        (acet * 1000 / wcet_ms) * 100);
+                } while (job(acet, start + duration,
                            lock_od, cs_length * 0.001));
         }