linux/include
Eric Dumazet 7004bf252c net: add tx_packets/tx_bytes/tx_dropped counters in struct netdev_queue
offsetof(struct net_device, features)=0x44
offsetof(struct net_device, stats.tx_packets)=0x54
offsetof(struct net_device, stats.tx_bytes)=0x5c
offsetof(struct net_device, stats.tx_dropped)=0x6c

Network drivers that touch dev->stats.tx_packets/stats.tx_bytes in their
tx path can slow down SMP operations, since they dirty a cache line
that should stay shared (dev->features is needed in rx and tx paths)

We could move away stats field in net_device but it wont help that much.
(Two cache lines dirtied in tx path, we can do one only)

Better solution is to add tx_packets/tx_bytes/tx_dropped in struct
netdev_queue because this structure is already touched in tx path and
counters updates will then be free (no increase in size)

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-05-18 15:15:06 -07:00
..
acpi Merge branches 'release', 'APERF', 'ARAT', 'misc', 'kelvin', 'device-lock' and 'bjorn.notify' into release 2009-04-07 18:18:42 -04:00
asm-arm
asm-generic percpu: unbreak alpha percpu 2009-04-10 21:36:18 +02:00
asm-h8300
asm-m32r Merge branch 'tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-04-05 11:04:19 -07:00
crypto
drm
keys
linux net: add tx_packets/tx_bytes/tx_dropped counters in struct netdev_queue 2009-05-18 15:15:06 -07:00
math-emu
media V4L/DVB (11381): ivtv/cx18: remove VIDIOC_INT_S_AUDIO_ROUTING debug support. 2009-04-06 21:44:28 -03:00
mtd
net Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-next-2.6 2009-05-18 14:48:30 -07:00
pcmcia
rdma
rxrpc
scsi fcoe: adds spma mode support 2009-05-17 21:04:08 -07:00
sound
trace tracing/syscalls: use a dedicated file header 2009-04-09 05:43:32 +02:00
video tdfxfb: move I2C functionality into the tdfxfb 2009-04-07 08:31:08 -07:00
xen
Kbuild