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| author | Hagen Paul Pfeifer <hagen@jauu.net> | 2013-10-22 23:27:06 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2013-10-26 01:03:39 +0200 |
| commit | 4a3ad7b3eade08ad1c760aaa4fe06a36f2584939 (patch) | |
| tree | 0006fbd7b270176d09bd80e6c7095e380c693571 /net/sched/sch_netem.c | |
| parent | Merge tag 'batman-adv-for-davem' of git://git.open-mesh.org/linux-merge (diff) | |
| download | linux-4a3ad7b3eade08ad1c760aaa4fe06a36f2584939.tar.xz linux-4a3ad7b3eade08ad1c760aaa4fe06a36f2584939.zip | |
netem: markov loss model transition fix
The transition from markov state "3 => lost packets within a burst
period" to "1 => successfully transmitted packets within a gap period"
has no *additional* loss event. The loss already happen for transition
from 1 -> 3, this additional loss will make things go wild.
E.g. transition probabilities:
p13: 10%
p31: 100%
Expected:
Ploss = p13 / (p13 + p31)
Ploss = ~9.09%
... but it isn't. Even worse: we get a double loss - each time.
So simple don't return true to indicate loss, rather break and return
false.
Signed-off-by: Hagen Paul Pfeifer <hagen@jauu.net>
Cc: Stephen Hemminger <stephen@networkplumber.org>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Stefano Salsano <stefano.salsano@uniroma2.it>
Cc: Fabio Ludovici <fabio.ludovici@yahoo.it>
Signed-off-by: Hagen Paul Pfeifer <hagen@jauu.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to '')
| -rw-r--r-- | net/sched/sch_netem.c | 1 |
1 files changed, 0 insertions, 1 deletions
diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c index b87e83d07478..75c94e59a3bd 100644 --- a/net/sched/sch_netem.c +++ b/net/sched/sch_netem.c @@ -235,7 +235,6 @@ static bool loss_4state(struct netem_sched_data *q) clg->state = 2; else if (clg->a3 < rnd && rnd < clg->a2 + clg->a3) { clg->state = 1; - return true; } else if (clg->a2 + clg->a3 < rnd) { clg->state = 3; return true; |