kernel-fxtec-pro1x/include
Eric Dumazet 3b098e2d7c net: Consistent skb timestamping
With RPS inclusion, skb timestamping is not consistent in RX path.

If netif_receive_skb() is used, its deferred after RPS dispatch.

If netif_rx() is used, its done before RPS dispatch.

This can give strange tcpdump timestamps results.

I think timestamping should be done as soon as possible in the receive
path, to get meaningful values (ie timestamps taken at the time packet
was delivered by NIC driver to our stack), even if NAPI already can
defer timestamping a bit (RPS can help to reduce the gap)

Tom Herbert prefer to sample timestamps after RPS dispatch. In case
sampling is expensive (HPET/acpi_pm on x86), this makes sense.

Let admins switch from one mode to another, using a new
sysctl, /proc/sys/net/core/netdev_tstamp_prequeue

Its default value (1), means timestamps are taken as soon as possible,
before backlog queueing, giving accurate timestamps.

Setting a 0 value permits to sample timestamps when processing backlog,
after RPS dispatch, to lower the load of the pre-RPS cpu.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-05-15 23:57:10 -07:00
..
acpi acpi: Support IBM SMBus CMI devices 2010-03-24 14:38:37 +01:00
asm-generic dma-mapping: fix dma_sync_single_range_* 2010-05-11 17:33:41 -07:00
crypto
drm Merge branch 'drm-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6 2010-05-07 14:02:01 -07:00
keys
linux net: Consistent skb timestamping 2010-05-15 23:57:10 -07:00
math-emu
media V4L/DVB: saa7146: fix regression of the av7110/budget-av driver 2010-05-06 19:20:50 -03:00
mtd
net net: reserve ports for applications using fixed port numbers 2010-05-15 23:28:40 -07:00
pcmcia pcmcia: pcmcia_dev_present bugfix 2010-04-21 08:09:17 +02:00
rdma
rxrpc
scsi include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
sound Merge branch 'fix/asoc' into for-linus 2010-04-07 09:54:41 +02:00
trace Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-block 2010-04-09 11:50:29 -07:00
video
xen include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
Kbuild