linux/include
Eric Dumazet 10d3be5692 tcp-tso: do not split TSO packets at retransmit time
Linux TCP stack painfully segments all TSO/GSO packets before retransmits.

This was fine back in the days when TSO/GSO were emerging, with their
bugs, but we believe the dark age is over.

Keeping big packets in write queues, but also in stack traversal
has a lot of benefits.
 - Less memory overhead, because write queues have less skbs
 - Less cpu overhead at ACK processing.
 - Better SACK processing, as lot of studies mentioned how
   awful linux was at this ;)
 - Less cpu overhead to send the rtx packets
   (IP stack traversal, netfilter traversal, drivers...)
 - Better latencies in presence of losses.
 - Smaller spikes in fq like packet schedulers, as retransmits
   are not constrained by TCP Small Queues.

1 % packet losses are common today, and at 100Gbit speeds, this
translates to ~80,000 losses per second.
Losses are often correlated, and we see many retransmit events
leading to 1-MSS train of packets, at the time hosts are already
under stress.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-04-24 14:43:59 -04:00
..
acpi Merge branches 'acpi-processor' and 'acpi-cppc' 2016-03-14 14:20:33 +01:00
asm-generic arch, ftrace: for KASAN put hard/soft IRQ entries into separate sections 2016-03-25 16:37:42 -07:00
clocksource
crypto Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2016-03-17 11:33:45 -07:00
drm drm/ttm: use phys_addr_t for ttm_bus_placement 2016-04-04 17:00:01 -04:00
dt-bindings The clk changes for this release cycle are mostly dominated by 2016-03-23 06:06:45 -07:00
keys
kvm
linux Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf-next 2016-04-24 00:12:08 -04:00
math-emu
media Merge branch 'for-linus' of git://ftp.arm.linux.org.uk/~rmk/linux-arm 2016-03-19 16:31:54 -07:00
memory
misc
net tcp-tso: do not split TSO packets at retransmit time 2016-04-24 14:43:59 -04:00
pcmcia
ras
rdma Round two of 4.6 merge window patches 2016-03-22 15:48:44 -07:00
rxrpc rxrpc: Static arrays of strings should be const char *const[] 2016-04-11 15:34:40 -04:00
scsi Merge branch 'fixes-base' into fixes 2016-04-05 06:56:47 -04:00
soc IOMMU Updates for Linux v4.6 2016-03-22 11:57:43 -07:00
sound ASoC: Updates for v4.6 2016-03-14 14:03:29 +01:00
target target: add a new add_wwn_groups fabrics method 2016-03-30 20:06:44 -07:00
trace perf, bpf: minimize the size of perf_trace_() tracepoint handler 2016-04-21 13:48:20 -04:00
uapi xfrm: align nlattr properly when needed 2016-04-23 20:13:25 -04:00
video gpu: ipu-v3: ipu-dmfc: Rename ipu_dmfc_init_channel to ipu_dmfc_config_wait4eot 2016-03-31 11:24:33 +02:00
xen xen-netback: re-import canonical netif header 2016-03-13 22:08:01 -04:00
Kbuild