mirror of
git://projects.qi-hardware.com/openwrt-xburst.git
synced 2024-12-30 23:56:27 +02:00
ab27b3f74d
One condition before codel_Newton_step() was not good if we never left the dropping state for a flow. As a result rec_inv_sqrt was 0, instead of the ~0 initial value. codel control law was then set to a very aggressive mode, dropping many packets before reaching 'target' and recovering from this problem. Brought over from 3.5-stable Signed-off-by: Dave Taht <dave.taht@bufferbloat.net> git-svn-id: svn://svn.openwrt.org/openwrt/trunk@32950 3c298f89-4303-0410-b956-a3cf2f4a3e73
69 lines
2.3 KiB
Diff
69 lines
2.3 KiB
Diff
From patchwork Mon Jul 30 06:52:21 2012
|
|
Content-Type: text/plain; charset="utf-8"
|
|
MIME-Version: 1.0
|
|
Content-Transfer-Encoding: 7bit
|
|
Subject: codel: refine one condition to avoid a nul rec_inv_sqrt
|
|
Date: Sun, 29 Jul 2012 20:52:21 -0000
|
|
From: Eric Dumazet <eric.dumazet@gmail.com>
|
|
X-Patchwork-Id: 173968
|
|
Message-Id: <1343631141.2626.13293.camel@edumazet-glaptop>
|
|
To: David Miller <davem@davemloft.net>
|
|
Cc: netdev <netdev@vger.kernel.org>, Anton Mich <lp2s1h@gmail.com>
|
|
|
|
From: Eric Dumazet <edumazet@google.com>
|
|
|
|
One condition before codel_Newton_step() was not good if
|
|
we never left the dropping state for a flow. As a result
|
|
rec_inv_sqrt was 0, instead of the ~0 initial value.
|
|
|
|
codel control law was then set to a very aggressive mode, dropping
|
|
many packets before reaching 'target' and recovering from this problem.
|
|
|
|
To keep codel_vars_init() as efficient as possible, refine
|
|
the condition to make sure rec_inv_sqrt initial value is correct
|
|
|
|
Many thanks to Anton Mich for discovering the issue and suggesting
|
|
a fix.
|
|
|
|
Reported-by: Anton Mich <lp2s1h@gmail.com>
|
|
Signed-off-by: Eric Dumazet <edumazet@google.com>
|
|
|
|
---
|
|
include/net/codel.h | 8 ++++++--
|
|
1 file changed, 6 insertions(+), 2 deletions(-)
|
|
|
|
|
|
|
|
--
|
|
To unsubscribe from this list: send the line "unsubscribe netdev" in
|
|
the body of a message to majordomo@vger.kernel.org
|
|
More majordomo info at http://vger.kernel.org/majordomo-info.html
|
|
|
|
diff --git a/include/net/codel.h b/include/net/codel.h
|
|
index 550debf..389cf62 100644
|
|
--- a/include/net/codel.h
|
|
+++ b/include/net/codel.h
|
|
@@ -305,6 +305,8 @@ static struct sk_buff *codel_dequeue(struct Qdisc *sch,
|
|
}
|
|
}
|
|
} else if (drop) {
|
|
+ u32 delta;
|
|
+
|
|
if (params->ecn && INET_ECN_set_ce(skb)) {
|
|
stats->ecn_mark++;
|
|
} else {
|
|
@@ -320,9 +322,11 @@ static struct sk_buff *codel_dequeue(struct Qdisc *sch,
|
|
* assume that the drop rate that controlled the queue on the
|
|
* last cycle is a good starting point to control it now.
|
|
*/
|
|
- if (codel_time_before(now - vars->drop_next,
|
|
+ delta = vars->count - vars->lastcount;
|
|
+ if (delta > 1 &&
|
|
+ codel_time_before(now - vars->drop_next,
|
|
16 * params->interval)) {
|
|
- vars->count = (vars->count - vars->lastcount) | 1;
|
|
+ vars->count = delta;
|
|
/* we dont care if rec_inv_sqrt approximation
|
|
* is not very precise :
|
|
* Next Newton steps will correct it quadratically.
|