Remove old delay loop configuration cruft from rtspin

Using cputime() is much more accurate than the old delay loop
auto-configuration. There is no good reason to keep it around.

1 files changed, 9 insertions, 69 deletions

diff --git a/bin/rtspin.c b/bin/rtspin.c
index 3e22ffe..75e9494 100644
--- a/bin/rtspin.c
+++ b/bin/rtspin.c
@@ -112,7 +112,6 @@ static void get_exec_times(const char *file, const int column,
 
 #define NUMS 4096
 static int num[NUMS];
-static double loop_length = 1.0;
 static char* progname;
 
 static int loop_once(void)
@@ -125,19 +124,17 @@ static int loop_once(void)
 
 static int loop_for(double exec_time, double emergency_exit)
 {
-        double t = 0;
+        double last_loop = 0, loop_start;
         int tmp = 0;
-/*      while (t + loop_length < exec_time) {
-                tmp += loop_once();
-                t += loop_length;
-        }
-*/
+
         double start = cputime();
         double now = cputime();
-        while (now + loop_length < start + exec_time) {
+
+        while (now + last_loop < start + exec_time) {
+                loop_start = now;
                 tmp += loop_once();
-                t += loop_length;
                 now = cputime();
+                last_loop = loop_start - now;
                 if (emergency_exit && wctime() > emergency_exit) {
                         /* Oops --- this should only be possible if the execution time tracking
                          * is broken in the LITMUS^RT kernel. */
@@ -150,50 +147,11 @@ static int loop_for(double exec_time, double emergency_exit)
         return tmp;
 }
 
-static void fine_tune(double interval)
-{
-        double start, end, delta;
-
-        start = wctime();
-        loop_for(interval, 0);
-        end = wctime();
-        delta = (end - start - interval) / interval;
-        if (delta != 0)
-                loop_length = loop_length / (1 - delta);
-}
-
-static void configure_loop(void)
-{
-        double start;
-
-        /* prime cache */
-        loop_once();
-        loop_once();
-        loop_once();
-
-        /* measure */
-        start = wctime();
-        loop_once(); /* hope we didn't get preempted  */
-        loop_length = wctime();
-        loop_length -= start;
-
-        /* fine tune */
-        fine_tune(0.1);
-        fine_tune(0.1);
-        fine_tune(0.1);
-}
-
-static void show_loop_length(void)
-{
-        printf("%s/%d: loop_length=%f (%ldus)\n",
-               progname, getpid(), loop_length,
-               (long) (loop_length * 1000000));
-}
 
 static void debug_delay_loop(void)
 {
         double start, end, delay;
-        show_loop_length();
+
         while (1) {
                 for (delay = 0.5; delay > 0.01; delay -= 0.01) {
                         start = wctime();
@@ -219,9 +177,9 @@ static int job(double exec_time, double program_end)
         }
 }
 
-#define OPTSTR "p:c:wld:veo:f:s:"
+#define OPTSTR "p:c:wlveo:f:s:"
 
-int main(int argc, char** argv) 
+int main(int argc, char** argv)
 {
         int ret;
         lt_t wcet;
@@ -232,8 +190,6 @@ int main(int argc, char** argv)
         int opt;
         int wait = 0;
         int test_loop = 0;
-        int skip_config = 0;
-        int verbose = 0;
         int column = 1;
         const char *file = NULL;
         int want_enforcement = 0;
@@ -265,15 +221,6 @@ int main(int argc, char** argv)
                 case 'l':
                         test_loop = 1;
                         break;
-                case 'd':
-                        /* manually configure delay per loop iteration 
-                         * unit: microseconds */
-                        loop_length = atof(optarg) / 1000000;
-                        skip_config = 1;
-                        break;
-                case 'v':
-                        verbose = 1;
-                        break;
                 case 'o':
                         column = atoi(optarg);
                         break;
@@ -293,10 +240,6 @@ int main(int argc, char** argv)
                 }
         }
 
-
-        if (!skip_config)
-                configure_loop();
-
         if (test_loop) {
                 debug_delay_loop();
                 return 0;
@@ -354,9 +297,6 @@ int main(int argc, char** argv)
         if (ret < 0)
                 bail_out("could not setup rt task params");
 
-        if (verbose)
-                show_loop_length();
-
         init_litmus();
 
         ret = task_mode(LITMUS_RT_TASK);