Re: [PATCH net-next v2] net: ipv6: avoid overhead when no custom FIB rules are installed

On 8/8/17 12:23 PM, Vincent Bernat wrote:

If the user hasn't installed any custom rules, don't go through the
whole FIB rules layer. This is pretty similar to f4530fa574df (ipv4:
Avoid overhead when no custom FIB rules are installed).

Using a micro-benchmark module [1], timing ip6_route_output() with
get_cycles(), with 40,000 routes in the main routing table, before this
patch:

...

At the frequency of the host during the bench (~ 3.7 GHz), this is
about a 100 ns difference on the median value.

A next step would be to collapse local and main tables, as in
0ddcf43d5d4a (ipv4: FIB Local/MAIN table collapse).

[1]: https://github.com/vincentbernat/network-lab/blob/master/lab-routes-ipv6/kbench_mod.c

Signed-off-by: Vincent Bernat <redacted>
Reviewed-by: Jiri Pirko <redacted>
---
 include/net/netns/ipv6.h |  1 +
 net/ipv6/fib6_rules.c    | 40 +++++++++++++++++++++++++++-------------
 net/ipv6/route.c         |  1 +
 3 files changed, 29 insertions(+), 13 deletions(-)

LGTM.

Acked-by: David Ahern <redacted>