linux/include
Eric Dumazet 0e280af026 tcp: introduce TCPSpuriousRtxHostQueues SNMP counter
Host queues (Qdisc + NIC) can hold packets so long that TCP can
eventually retransmit a packet before the first transmit even left
the host.

Its not clear right now if we could avoid this in the first place :

- We could arm RTO timer not at the time we enqueue packets, but
  at the time we TX complete them (tcp_wfree())

- Cancel the sending of the new copy of the packet if prior one
  is still in queue.

This patch adds instrumentation so that we can at least see how
often this problem happens.

TCPSpuriousRtxHostQueues SNMP counter is incremented every time
we detect the fast clone is not yet freed in tcp_transmit_skb()

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Tom Herbert <therbert@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2013-04-18 14:57:25 -04:00
..
acpi Fixes: 2013-03-12 20:25:53 -07:00
asm-generic asm-generic: move cmpxchg*_local defs to cmpxchg.h 2013-03-13 06:11:05 +01:00
clocksource ImgTec Meta architecture changes for v3.9-rc1 2013-03-03 12:06:09 -08:00
crypto
drm drm/radeon: add Richland pci ids 2013-03-15 18:47:19 -04:00
keys
linux Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/jesse/openvswitch 2013-04-17 13:30:32 -04:00
math-emu
media
memory
misc
net net: sctp: sctp_ulpq: remove 'malloced' struct member 2013-04-17 14:13:02 -04:00
pcmcia
ras edac: add support for error type "Info" 2013-02-21 14:16:27 -03:00
rdma IB/core: Add "type 2" memory windows support 2013-02-21 11:51:45 -08:00
rxrpc
scsi libfc, fcoe, bnx2fc: Split fc_disc_init into fc_disc_{init, config} 2013-03-25 16:03:03 -07:00
sound Merge remote-tracking branch 'asoc/fix/max98090' into asoc-next 2013-03-26 14:08:03 +00:00
target target: Rename spc_get_write_same_sectors -> sbc_get_write_same_sectors 2013-02-23 12:46:14 -08:00
trace Various bug fixes for ext4. The most important is a fix for the new 2013-03-02 19:33:21 -08:00
uapi tcp: introduce TCPSpuriousRtxHostQueues SNMP counter 2013-04-18 14:57:25 -04:00
video ARM: at91: fix LCD-wiring mode 2013-03-13 11:05:04 +01:00
xen for-linus-20130331 2013-03-31 11:38:59 -07:00
Kbuild