On Fri, 2012-04-06 at 09:14 +0200, Juri Lelli wrote:+static
+int dl_runtime_exceeded(struct rq *rq, struct sched_dl_entity *dl_se)
+{
+ int dmiss = dl_time_before(dl_se->deadline, rq->clock);
+ int rorun = dl_se->runtime<= 0;
+
+ if (!rorun&& !dmiss)
+ return 0;
+
+ /*
+ * If we are beyond our current deadline and we are still
+ * executing, then we have already used some of the runtime of
+ * the next instance. Thus, if we do not account that, we are
+ * stealing bandwidth from the system at each deadline miss!
+ */
+ if (dmiss) {
+ dl_se->runtime = rorun ? dl_se->runtime : 0;
+ dl_se->runtime -= rq->clock - dl_se->deadline;
+ }
So ideally this can't happen, but since we already leak time from the
system through means of hardirq / kstop / context-switch-overhead /
clock-jitter etc.. we avoid the error accumulating?
+
+ return 1;
+}