From dca145ffaa8d39ea1904491ac81b92b7049372c0 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Mon, 27 Oct 2014 21:45:24 -0700 Subject: tcp: allow for bigger reordering level While testing upcoming Yaogong patch (converting out of order queue into an RB tree), I hit the max reordering level of linux TCP stack. Reordering level was limited to 127 for no good reason, and some network setups [1] can easily reach this limit and get limited throughput. Allow a new max limit of 300, and add a sysctl to allow admins to even allow bigger (or lower) values if needed. [1] Aggregation of links, per packet load balancing, fabrics not doing deep packet inspections, alternative TCP congestion modules... Signed-off-by: Eric Dumazet Cc: Yaogong Wang Signed-off-by: David S. Miller --- Documentation/networking/bonding.txt | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) (limited to 'Documentation/networking/bonding.txt') diff --git a/Documentation/networking/bonding.txt b/Documentation/networking/bonding.txt index eeb5b2e97bed..83bf4986baea 100644 --- a/Documentation/networking/bonding.txt +++ b/Documentation/networking/bonding.txt @@ -2230,11 +2230,8 @@ balance-rr: This mode is the only mode that will permit a single It is possible to adjust TCP/IP's congestion limits by altering the net.ipv4.tcp_reordering sysctl parameter. The - usual default value is 3, and the maximum useful value is 127. - For a four interface balance-rr bond, expect that a single - TCP/IP stream will utilize no more than approximately 2.3 - interface's worth of throughput, even after adjusting - tcp_reordering. + usual default value is 3. But keep in mind TCP stack is able + to automatically increase this when it detects reorders. Note that the fraction of packets that will be delivered out of order is highly variable, and is unlikely to be zero. The level -- cgit v1.2.3-55-g7522