linux/include
Yaogong Wang 9f5afeae51 tcp: use an RB tree for ooo receive queue
Over the years, TCP BDP has increased by several orders of magnitude,
and some people are considering to reach the 2 Gbytes limit.

Even with current window scale limit of 14, ~1 Gbytes maps to ~740,000
MSS.

In presence of packet losses (or reorders), TCP stores incoming packets
into an out of order queue, and number of skbs sitting there waiting for
the missing packets to be received can be in the 10^5 range.

Most packets are appended to the tail of this queue, and when
packets can finally be transferred to receive queue, we scan the queue
from its head.

However, in presence of heavy losses, we might have to find an arbitrary
point in this queue, involving a linear scan for every incoming packet,
throwing away cpu caches.

This patch converts it to a RB tree, to get bounded latencies.

Yaogong wrote a preliminary patch about 2 years ago.
Eric did the rebase, added ofo_last_skb cache, polishing and tests.

Tested with network dropping between 1 and 10 % packets, with good
success (about 30 % increase of throughput in stress tests)

Next step would be to also use an RB tree for the write queue at sender
side ;)

Signed-off-by: Yaogong Wang <wygivan@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Acked-By: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-09-08 17:25:58 -07:00
..
acpi treewide: replace obsolete _refok by __ref 2016-08-02 17:31:41 -04:00
asm-generic locking/qrwlock: Fix write unlock bug on big endian systems 2016-08-10 14:13:27 +02:00
clocksource
crypto A number of improvements for the /dev/random driver; the most 2016-07-27 15:11:55 -07:00
drm Merge branch 'drm-next-4.8' of git://people.freedesktop.org/~agd5f/linux into drm-next 2016-08-08 16:45:33 +10:00
dt-bindings ARM: DT updates for v4.8 2016-08-01 18:37:45 -04:00
keys
kvm KVM/ARM Changes for v4.8 - Take 2 2016-08-04 13:59:56 +02:00
linux tcp: use an RB tree for ooo receive queue 2016-09-08 17:25:58 -07:00
math-emu
media dma-mapping: use unsigned long for dma_attrs 2016-08-04 08:50:07 -04:00
memory
misc
net tcp: use an RB tree for ooo receive queue 2016-09-08 17:25:58 -07:00
pcmcia
ras
rdma IB/core: Use memdup_user() rather than duplicating its implementation 2016-08-23 12:40:13 -04:00
rxrpc rxrpc: Randomise epoch and starting client conn ID values 2016-09-04 21:41:39 +01:00
scsi Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending 2016-08-04 20:04:37 -04:00
soc ARM: SoC driver updates for v4.8 2016-08-01 18:36:01 -04:00
sound Merge tag 'drm-for-v4.8' of git://people.freedesktop.org/~airlied/linux 2016-08-01 21:44:08 -04:00
target
trace rxrpc: Add tracepoint for working out where aborts happen 2016-09-07 16:34:40 +01:00
uapi openvswitch: 802.1ad uapi changes. 2016-09-08 17:10:27 -07:00
video
xen xen: change the type of xen_vcpu_id to uint32_t 2016-08-24 18:17:27 +01:00
Kbuild