diff options
Diffstat (limited to 'target/linux/generic/patches-3.3/049-codel-refine-one-condition-to-avoid-a-nul-rec_inv_sqrt.patch')
| -rw-r--r-- | target/linux/generic/patches-3.3/049-codel-refine-one-condition-to-avoid-a-nul-rec_inv_sqrt.patch | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/target/linux/generic/patches-3.3/049-codel-refine-one-condition-to-avoid-a-nul-rec_inv_sqrt.patch b/target/linux/generic/patches-3.3/049-codel-refine-one-condition-to-avoid-a-nul-rec_inv_sqrt.patch new file mode 100644 index 000000000..bfb6ae205 --- /dev/null +++ b/target/linux/generic/patches-3.3/049-codel-refine-one-condition-to-avoid-a-nul-rec_inv_sqrt.patch @@ -0,0 +1,52 @@ +From b8fc328668a74e1314a19266755a54abd875e5a6 Mon Sep 17 00:00:00 2001 +From: Eric Dumazet <edumazet@google.com> +Date: Sun, 29 Jul 2012 20:52:21 +0000 +Subject: [PATCH] codel: refine one condition to avoid a nul rec_inv_sqrt + +commit 2359a47671fc4fb0fe5e9945f76c2cb10792c0f8 upstream. + +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> +Signed-off-by: David S. Miller <davem@davemloft.net> +--- + include/net/codel.h | 8 ++++++-- + 1 file changed, 6 insertions(+), 2 deletions(-) + +--- a/include/net/codel.h ++++ b/include/net/codel.h +@@ -305,6 +305,8 @@ static struct sk_buff *codel_dequeue(str + } + } + } 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(str + * 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. |