rtspin: use POSIX clock to better approximate runtime

this finally appears to work reasonably on Flare

2 files changed, 31 insertions, 6 deletions

diff --git a/SConstruct b/SConstruct
index ecb4b4f..a3a7ea4 100644
--- a/SConstruct
+++ b/SConstruct
@@ -91,7 +91,7 @@ st = env.Clone(
 
 # link with liblitmus
 rt = env.Clone(
-    LIBS     = 'litmus',
+    LIBS     = Split('litmus rt'),
     LIBPATH  = '.'
 )
 rt.Append(LINKFLAGS = '-static')
diff --git a/bin/rtspin.c b/bin/rtspin.c
index 56f5549..7829942 100644
--- a/bin/rtspin.c
+++ b/bin/rtspin.c
@@ -10,6 +10,16 @@
 #include "common.h"
 
 
+static double cputime()
+{
+        struct timespec ts;
+        int err;
+        err = clock_gettime(CLOCK_THREAD_CPUTIME_ID, &ts);
+        if (err != 0)
+                perror("clock_gettime");
+        return (ts.tv_sec + 1E-9 * ts.tv_nsec);
+}
+
 static double wctime()
 {
         struct timeval tv;
@@ -40,11 +50,20 @@ static int loop_once(void)
 static int loop_for(double exec_time)
 {
         double t = 0;
-        int tmp = 0;
-        while (t + loop_length < exec_time) {
+        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) {
                 tmp += loop_once();
                 t += loop_length;
+                now = cputime();
         }
+
         return tmp;
 }
 
@@ -106,7 +125,7 @@ static int job(double exec_time)
         return 0;
 }
 
-#define OPTSTR "p:c:wl"
+#define OPTSTR "p:c:wld:"
 
 int main(int argc, char** argv) 
 {
@@ -118,6 +137,7 @@ int main(int argc, char** argv)
         int opt;
         int wait = 0;
         int test_loop = 0;
+        int skip_config = 0;
         double duration, start;
         task_class_t class = RT_CLASS_HARD;
 
@@ -138,6 +158,10 @@ int main(int argc, char** argv)
                 case 'l':
                         test_loop = 1;
                         break;
+                case 'd':
+                        loop_length = atof(optarg) / 1000000;                   
+                        skip_config = 1;
+                        break;
                 case ':':
                         usage("Argument missing.");
                         break;
@@ -148,8 +172,9 @@ int main(int argc, char** argv)
                 }
         }
 
-
-        configure_loop();
+        
+        if (!skip_config)
+                configure_loop();
 
         if (test_loop) {
                 debug_delay_loop();