Eric Dumazet 971f10eca1 tcp: better TCP_SKB_CB layout to reduce cache line misses ... TCP maintains lists of skb in write queue, and in receive queues (in order and out of order queues) Scanning these lists both in input and output path usually requires access to skb->next, TCP_SKB_CB(skb)->seq, and TCP_SKB_CB(skb)->end_seq These fields are currently in two different cache lines, meaning we waste lot of memory bandwidth when these queues are big and flows have either packet drops or packet reorders. We can move TCP_SKB_CB(skb)->header at the end of TCP_SKB_CB, because this header is not used in fast path. This allows TCP to search much faster in the skb lists. Even with regular flows, we save one cache line miss in fast path. Thanks to Christoph Paasch for noticing we need to cleanup skb->cb[] (IPCB/IP6CB) before entering IP stack in tx path, and that I forgot IPCB use in tcp_v4_hnd_req() and tcp_v4_save_options(). Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>		2014-09-28 16:35:43 -04:00
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acpi
asm-generic
clocksource
crypto
drm
dt-bindings
keys
kvm
linux	net: introduce __skb_header_release()	2014-09-26 15:40:06 -04:00
math-emu
media	[media] vb2: fix VBI/poll regression	2014-09-21 20:57:30 -03:00
memory
misc
net	tcp: better TCP_SKB_CB layout to reduce cache line misses	2014-09-28 16:35:43 -04:00
pcmcia
ras
rdma
rxrpc
scsi
soc/tegra
sound
target
trace
uapi	Merge tag 'master-2014-09-16' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-next	2014-09-26 15:39:24 -04:00
video
xen
Kbuild