From: "Mohit P. Tahiliani" <tahili...@nitk.edu.in>
The update in drop probability depends on the parameters
alpha and beta, which in turn reflect the current congestion
level. However, the previous if-else cases were recommended
when the supported bandwidth was up to 12 Mbps but, current
data links support a much higher bandwidth, and the
requirement for more bandwidth is in never-ending demand.
Hence, RFC 8033 suggests using more if-else cases for better
fine-tuning of parameters alpha and beta in order to control
the congestion as much as possible.
Signed-off-by: Mohit P. Tahiliani <tahili...@nitk.edu.in>
Signed-off-by: Dhaval Khandla <dhavaljkhandl...@gmail.com>
Signed-off-by: Hrishikesh Hiraskar <hrishihiras...@gmail.com>
Signed-off-by: Manish Kumar B <bmanish15...@gmail.com>
Signed-off-by: Sachin D. Patil <sdp.sac...@gmail.com>
Signed-off-by: Leslie Monis <lesliemo...@gmail.com>
---
net/sched/sch_pie.c | 26 +++++++++++++++++++++++---
1 file changed, 23 insertions(+), 3 deletions(-)
diff --git a/net/sched/sch_pie.c b/net/sched/sch_pie.c
index f4e189a..c84e91e 100644
--- a/net/sched/sch_pie.c
+++ b/net/sched/sch_pie.c
@@ -343,10 +343,30 @@ static void calculate_probability(struct Qdisc *sch)
* appropriately 2) scaling down by 16 to come to 0-2 range.
* Please see paper for details.
*
- * We scale alpha and beta differently depending on whether we are in
- * light, medium or high dropping mode.
+ * We scale alpha and beta differently depending on how heavy the
+ * congestion is.
*/
- if (q->vars.prob < MAX_PROB / 100) {
+ if (q->vars.prob < MAX_PROB / 1000000) {
+ alpha =
+ (q->params.alpha * (MAX_PROB / PSCHED_TICKS_PER_SEC)) >> 15;
+ beta =
+ (q->params.beta * (MAX_PROB / PSCHED_TICKS_PER_SEC)) >> 15;
+ } else if (q->vars.prob < MAX_PROB / 100000) {
+ alpha =
+ (q->params.alpha * (MAX_PROB / PSCHED_TICKS_PER_SEC)) >> 13;
+ beta =
+ (q->params.beta * (MAX_PROB / PSCHED_TICKS_PER_SEC)) >> 13;
+ } else if (q->vars.prob < MAX_PROB / 10000) {
+ alpha =
+ (q->params.alpha * (MAX_PROB / PSCHED_TICKS_PER_SEC)) >> 11;
+ beta =
+ (q->params.beta * (MAX_PROB / PSCHED_TICKS_PER_SEC)) >> 11;
+ } else if (q->vars.prob < MAX_PROB / 1000) {
+ alpha =
+ (q->params.alpha * (MAX_PROB / PSCHED_TICKS_PER_SEC)) >> 9;
+ beta =
+ (q->params.beta * (MAX_PROB / PSCHED_TICKS_PER_SEC)) >> 9;
+ } else if (q->vars.prob < MAX_PROB / 100) {
alpha =
(q->params.alpha * (MAX_PROB / PSCHED_TICKS_PER_SEC)) >> 7;
beta =
--
2.7.4
