@@ -, +, @@ 
---
 sys/cam/cam_iosched.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)
--- b/sys/cam/cam_iosched.c	
+++ b/sys/cam/cam_iosched.c	
@@ -415,6 +415,7 @@ cam_iosched_iops_init(struct iop_stats *ios)
 	ios->l_value1 = ios->current / ios->softc->quanta;
 	if (ios->l_value1 <= 0)
 		ios->l_value1 = 1;
+	ios->l_value2 = 0;
 
 	return 0;
 }
@@ -423,9 +424,18 @@ static int
 cam_iosched_iops_tick(struct iop_stats *ios)
 {
 
+	if ((ios->softc->total_ticks % ios->softc->quanta) == 0)
+		ios->l_value2 = 0;
+
 	ios->l_value1 = (int)((ios->current * (uint64_t)ios->softc->this_frac) >> 16);
-	if (ios->l_value1 <= 0)
+	/*
+	 * Allow at least one IO per tick until all
+	 * the IOs for this interval have been spent.
+	 */
+	if (ios->l_value1 <= 0 && ios->l_value2 < ios->current) {
 		ios->l_value1 = 1;
+		ios->l_value2++;
+	}
 
 	return 0;
 }
-- 
 discarding 'unspent' ios
---
 sys/cam/cam_iosched.c | 22 ++++++++++++++++------
 1 file changed, 16 insertions(+), 6 deletions(-)
--- b/sys/cam/cam_iosched.c	
+++ b/sys/cam/cam_iosched.c	
@@ -423,20 +423,30 @@ cam_iosched_iops_init(struct iop_stats *ios)
 static int
 cam_iosched_iops_tick(struct iop_stats *ios)
 {
+	int new_ios;
 
-	if ((ios->softc->total_ticks % ios->softc->quanta) == 0)
-		ios->l_value2 = 0;
-
-	ios->l_value1 = (int)((ios->current * (uint64_t)ios->softc->this_frac) >> 16);
+	new_ios = (int)((ios->current * (uint64_t)ios->softc->this_frac) >> 16);
 	/*
 	 * Allow at least one IO per tick until all
 	 * the IOs for this interval have been spent.
 	 */
-	if (ios->l_value1 <= 0 && ios->l_value2 < ios->current) {
-		ios->l_value1 = 1;
+	if (new_ios < 1 && ios->l_value2 < ios->current) {
+		new_ios = 1;
 		ios->l_value2++;
 	}
 
+        /*
+         * If this a new accounting interval, discard any "unspent" ios
+         * granted in the previous interval.  Otherwise add the new ios to
+         * the previously granted ones that haven't been spent yet.
+         */
+	if ((ios->softc->total_ticks % ios->softc->quanta) == 0) {
+		ios->l_value1 = new_ios;
+		ios->l_value2 = 1;
+	} else {
+		ios->l_value1 += new_ios;
+	}
+
 	return 0;
 }
 
--