linux/include
Tom Herbert cb1ce2ef38 ipv6: Implement automatic flow label generation on transmit
Automatically generate flow labels for IPv6 packets on transmit.
The flow label is computed based on skb_get_hash. The flow label will
only automatically be set when it is zero otherwise (i.e. flow label
manager hasn't set one). This supports the transmit side functionality
of RFC 6438.

Added an IPv6 sysctl auto_flowlabels to enable/disable this behavior
system wide, and added IPV6_AUTOFLOWLABEL socket option to enable this
functionality per socket.

By default, auto flowlabels are disabled to avoid possible conflicts
with flow label manager, however if this feature proves useful we
may want to enable it by default.

It should also be noted that FreeBSD has already implemented automatic
flow labels (including the sysctl and socket option). In FreeBSD,
automatic flow labels default to enabled.

Performance impact:

Running super_netperf with 200 flows for TCP_RR and UDP_RR for
IPv6. Note that in UDP case, __skb_get_hash will be called for
every packet with explains slight regression. In the TCP case
the hash is saved in the socket so there is no regression.

Automatic flow labels disabled:

  TCP_RR:
    86.53% CPU utilization
    127/195/322 90/95/99% latencies
    1.40498e+06 tps

  UDP_RR:
    90.70% CPU utilization
    118/168/243 90/95/99% latencies
    1.50309e+06 tps

Automatic flow labels enabled:

  TCP_RR:
    85.90% CPU utilization
    128/199/337 90/95/99% latencies
    1.40051e+06

  UDP_RR
    92.61% CPU utilization
    115/164/236 90/95/99% latencies
    1.4687e+06

Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-07-07 21:14:21 -07:00
..
acpi ACPI / processor replace __attribute__((packed)) by __packed 2014-06-17 14:00:15 +02:00
asm-generic Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-06-12 19:18:49 -07:00
clocksource
crypto crypto: hash - Add real ahash walk interface 2014-05-21 20:56:12 +08:00
drm drm/i915, HD-audio: Don't continue probing when nomodeset is given 2014-06-16 10:34:06 +02:00
dt-bindings The i.MX fixes for 3.16: 2014-06-23 14:12:48 +02:00
keys
kvm
linux ipv6: Implement automatic flow label generation on transmit 2014-07-07 21:14:21 -07:00
math-emu
media Merge branch 'topic/omap3isp' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media 2014-06-12 23:04:28 -07:00
memory
misc
net ipv6: Implement automatic flow label generation on transmit 2014-07-07 21:14:21 -07:00
pcmcia
ras
rdma Merge branches 'core', 'cxgb3', 'cxgb4', 'iser', 'iwpm', 'misc', 'mlx4', 'mlx5', 'noio', 'ocrdma', 'qib', 'srp' and 'usnic' into for-next 2014-06-10 10:12:14 -07:00
rxrpc
scsi Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending 2014-06-12 22:38:32 -07:00
sound ALSA: control: Protect user controls against concurrent access 2014-06-18 15:12:33 +02:00
target target: Report correct response length for some commands 2014-06-11 12:15:30 -07:00
trace tracing: Add __field_struct macro for TRACE_EVENT() 2014-06-21 00:18:42 -04:00
uapi ipv6: Implement automatic flow label generation on transmit 2014-07-07 21:14:21 -07:00
video Merge branch 'drm-next' of git://people.freedesktop.org/~airlied/linux 2014-06-12 11:32:30 -07:00
xen Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2014-06-12 14:27:40 -07:00
Kbuild