wr-servo: run twice as fast

The old code used to discard every other tuple, because when "wait for hardware was set", the code cleared the flag and did nothing. This was exposed by one of the clean-up passes, but I chose not to change the behaviour. Now I do the normal work when wait_for_hw gets cleared. However, as a side effect, wr_mon was always saying "wait for hardware", because any action would set the flag. Thus, the solution is not setting the flag in TRACK_PHASE, but only in the initial SYNC_SEC and SYNC_NSEC states. The code then checks if the hardware is busy, irrespective of any flag. The result in wr_mon is matching reality, and the code works twice as fast as it used to. Signed-off-by: Alessandro Rubini <rubini@gnudd.com>

wr-servo: run twice as fast
The old code used to discard every other tuple, because when "wait for hardware was set", the code cleared the flag and did nothing. This was exposed by one of the clean-up passes, but I chose not to change the behaviour. Now I do the normal work when wait_for_hw gets cleared. However, as a side effect, wr_mon was always saying "wait for hardware", because any action would set the flag. Thus, the solution is not setting the flag in TRACK_PHASE, but only in the initial SYNC_SEC and SYNC_NSEC states. The code then checks if the hardware is busy, irrespective of any flag. The result in wr_mon is matching reality, and the code works twice as fast as it used to. Signed-off-by: Alessandro Rubini <rubini@gnudd.com>
6ecdf970 · Alessandro Rubini · 11c199bc · 6ecdf970
Commit 6ecdf970 authored Jul 21, 2015 by Alessandro Rubini
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Showing with 5 additions and 11 deletions

wr-servo.c proto-ext-whiterabbit/wr-servo.c +5 -11

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--- a/proto-ext-whiterabbit/wr-servo.c
+++ b/proto-ext-whiterabbit/wr-servo.c
@@ -296,15 +296,11 @@ int wr_servo_update(struct pp_instance *ppi)
 		 * DSPOR(ppi)->doRestart = TRUE; */
 	}

-	/*
-	 * After each action on the hardware, we must verify if it is over.
-	 * However, we loose one iteration every two. To be audited later.
-	 */
-	if (s->flags & WR_FLAG_WAIT_HW) {
-		if (!wrp->ops->adjust_in_progress())
-			s->flags &= ~WR_FLAG_WAIT_HW;
-		else
-			pp_diag(ppi, servo, 1, "servo:busy\n");
+	/* After each action on the hardware, we must verify if it is over. */
+	if (!wrp->ops->adjust_in_progress()) {
+		s->flags &= ~WR_FLAG_WAIT_HW;
+	} else {
+		pp_diag(ppi, servo, 1, "servo:busy\n");
 		goto out;
 	}

@@ -407,8 +403,6 @@ int wr_servo_update(struct pp_instance *ppi)
 				s->cur_setpoint);

 			s->delta_ms_prev = s->delta_ms;
-			s->flags |= WR_FLAG_WAIT_HW;
-			s->state = WR_TRACK_PHASE;
 		}
 		break;