diff mbox series

[iproute2-next] tc: red: allow setting th_min and th_max to the same value

Message ID 20180116230850.25802-1-jakub.kicinski@netronome.com
State Accepted, archived
Delegated to: David Ahern
Headers show
Series [iproute2-next] tc: red: allow setting th_min and th_max to the same value | expand

Commit Message

Jakub Kicinski Jan. 16, 2018, 11:08 p.m. UTC 
Setting th_min and th_max to the same value may be useful for DCTCP
deployments.  The original DCTCP paper describes it as a simplest way
of achieving simple ECN threshold marking.  Indeed, there doesn't seem
to be any simpler qdisc in Linux which would allow such a setup today.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Dirk van der Merwe <dirk.vandermerwe@netronome.com>
---
Or should I go ahead and add a DCTCP qdisc? :)

 tc/tc_red.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

Comments

David Ahern Jan. 19, 2018, 8:37 p.m. UTC | #1 
On 1/16/18 3:08 PM, Jakub Kicinski wrote:
> Setting th_min and th_max to the same value may be useful for DCTCP
> deployments.  The original DCTCP paper describes it as a simplest way
> of achieving simple ECN threshold marking.  Indeed, there doesn't seem
> to be any simpler qdisc in Linux which would allow such a setup today.
> 
> Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
> Reviewed-by: Dirk van der Merwe <dirk.vandermerwe@netronome.com>
> ---
> Or should I go ahead and add a DCTCP qdisc? :)
> 
>  tc/tc_red.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 

applied to iproute2-next
diff mbox series

Patch

diff --git a/tc/tc_red.c b/tc/tc_red.c
index 1f82ef1aec65..178fe088f732 100644
--- a/tc/tc_red.c
+++ b/tc/tc_red.c
@@ -30,7 +30,9 @@  int tc_red_eval_P(unsigned int qmin, unsigned int qmax, double prob)
 {
 	int i = qmax - qmin;
 
-	if (i <= 0)
+	if (!i)
+		return 0;
+	if (i < 0)
 		return -1;
 
 	prob /= i;