Re: [net-next v1] net: ipv6: avoid overhead when no custom FIB rules are installed

2017-08-08 Thread Vincent Bernat 
 ❦  8 août 2017 08:46 -0600, David Ahern  :

>> diff --git a/net/ipv6/fib6_rules.c b/net/ipv6/fib6_rules.c
>> index 2f29e4e33bd3..693c27ede40e 100644
>> --- a/net/ipv6/fib6_rules.c
>> +++ b/net/ipv6/fib6_rules.c
>> @@ -63,19 +63,32 @@ unsigned int fib6_rules_seq_read(struct net *net)
>>  struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
>> int flags, pol_lookup_t lookup)
>>  {
>> -struct fib_lookup_arg arg = {
>> -.lookup_ptr = lookup,
>> -.flags = FIB_LOOKUP_NOREF,
>> -};
>> -
>>  /* update flow if oif or iif point to device enslaved to l3mdev */
>>  l3mdev_update_flow(net, flowi6_to_flowi(fl6));
>
> The l3mdev_update_flow can be moved to the has_custom_rules block.
> l3mdev requires FIB rules for the lookups to work, so no rules means no
> l3mdev configured.
>
> Rest looks good to me.

I suspected that it could be moved. I'll update the patch tomorrow.
-- 
Choose variable names that won't be confused.
- The Elements of Programming Style (Kernighan & Plauger)

Re: [net-next v1] net: ipv6: avoid overhead when no custom FIB rules are installed

2017-08-08 Thread David Ahern 
On 8/8/17 5:51 AM, Vincent Bernat wrote:
> diff --git a/net/ipv6/fib6_rules.c b/net/ipv6/fib6_rules.c
> index 2f29e4e33bd3..693c27ede40e 100644
> --- a/net/ipv6/fib6_rules.c
> +++ b/net/ipv6/fib6_rules.c
> @@ -63,19 +63,32 @@ unsigned int fib6_rules_seq_read(struct net *net)
>  struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
>  int flags, pol_lookup_t lookup)
>  {
> - struct fib_lookup_arg arg = {
> - .lookup_ptr = lookup,
> - .flags = FIB_LOOKUP_NOREF,
> - };
> -
>   /* update flow if oif or iif point to device enslaved to l3mdev */
>   l3mdev_update_flow(net, flowi6_to_flowi(fl6));

The l3mdev_update_flow can be moved to the has_custom_rules block.
l3mdev requires FIB rules for the lookups to work, so no rules means no
l3mdev configured.

Rest looks good to me.


>  
> - fib_rules_lookup(net->ipv6.fib6_rules_ops,
> -  flowi6_to_flowi(fl6), flags, );
> -
> - if (arg.result)
> - return arg.result;
> + if (net->ipv6.fib6_has_custom_rules) {
> + struct fib_lookup_arg arg = {
> + .lookup_ptr = lookup,
> + .flags = FIB_LOOKUP_NOREF,
> + };
> +
> + fib_rules_lookup(net->ipv6.fib6_rules_ops,
> +  flowi6_to_flowi(fl6), flags, );
> +
> + if (arg.result)
> + return arg.result;
> + } else {
> + struct rt6_info *rt;
> +
> + rt = lookup(net, net->ipv6.fib6_local_tbl, fl6, flags);
> + if (rt != net->ipv6.ip6_null_entry && rt->dst.error != -EAGAIN)
> + return >dst;
> + ip6_rt_put(rt);
> + rt = lookup(net, net->ipv6.fib6_main_tbl, fl6, flags);
> + if (rt->dst.error != -EAGAIN)
> + return >dst;
> + ip6_rt_put(rt);
> + }
>  
>   dst_hold(>ipv6.ip6_null_entry->dst);
>   return >ipv6.ip6_null_entry->dst;

Re: [net-next v1] net: ipv6: avoid overhead when no custom FIB rules are installed

2017-08-08 Thread Jiri Pirko 
Tue, Aug 08, 2017 at 01:51:21PM CEST, vinc...@bernat.im 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() using
>get_cycles(), on my laptop with performance governor (so, subject to
>some caution due to thermal throttling), with 40,000 routes in the main
>routing table, before this patch:
>
>min=603 max=12477 count=627 average=1926 95th=4518 90th=3661 50th=1600 
> mad=724
>table=254 avgdepth=21.8 maxdepth=39
>value │ ┊count
>  600 │▒▒  134
>  860 │▒▒▒░░91
> 1120 │▒▒▒░░39
> 1380 │░58
> 1640 │░░   57
> 1900 │░░   58
> 2160 │▒▒▒░░░   46
> 2420 │▒▒░░ 26
> 2680 │▒▒   27
> 2940 │▒░░  15
> 3200 │  8
> 3460 │░ 8
> 3720 │░░   12
> 3980 │░░9
> 4240 │░░░   7
> 4500 │░░░   6
>
>After:
>
>min=486 max=12390 count=627 average=1715 95th=4365 90th=3352 50th=1324 
> mad=631
>table=254 avgdepth=21.8 maxdepth=39
>value │ ┊count
>  480 │153
>  730 │▒▒▒  88
>  980 │░░░  57
> 1230 │ 56
> 1480 │▒▒▒  43
> 1730 │▒▒▒  50
> 1980 │▒▒   31
> 2230 │▒░░  23
> 2480 │▒15
> 2730 │▒░   23
> 2980 │▒░░░ 20
> 3230 │▒14
> 3480 │░░4
> 3730 │░░8
> 3980 │░░░   9
> 4230 │░░░   4

Cool graphs!


>
>At the frequency of the laptop during the bench (~ 2.3 GHz), this is
>about a 130 ns difference on the median value and 50 ns on the minimal
>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 

Reviewed-by: Jiri Pirko

[net-next v1] net: ipv6: avoid overhead when no custom FIB rules are installed

2017-08-08 Thread Vincent Bernat 
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() using
get_cycles(), on my laptop with performance governor (so, subject to
some caution due to thermal throttling), with 40,000 routes in the main
routing table, before this patch:

min=603 max=12477 count=627 average=1926 95th=4518 90th=3661 50th=1600 
mad=724
table=254 avgdepth=21.8 maxdepth=39
value │ ┊count
  600 │▒▒  134
  860 │▒▒▒░░91
 1120 │▒▒▒░░39
 1380 │░58
 1640 │░░   57
 1900 │░░   58
 2160 │▒▒▒░░░   46
 2420 │▒▒░░ 26
 2680 │▒▒   27
 2940 │▒░░  15
 3200 │  8
 3460 │░ 8
 3720 │░░   12
 3980 │░░9
 4240 │░░░   7
 4500 │░░░   6

After:

min=486 max=12390 count=627 average=1715 95th=4365 90th=3352 50th=1324 
mad=631
table=254 avgdepth=21.8 maxdepth=39
value │ ┊count
  480 │153
  730 │▒▒▒  88
  980 │░░░  57
 1230 │ 56
 1480 │▒▒▒  43
 1730 │▒▒▒  50
 1980 │▒▒   31
 2230 │▒░░  23
 2480 │▒15
 2730 │▒░   23
 2980 │▒░░░ 20
 3230 │▒14
 3480 │░░4
 3730 │░░8
 3980 │░░░   9
 4230 │░░░   4

At the frequency of the laptop during the bench (~ 2.3 GHz), this is
about a 130 ns difference on the median value and 50 ns on the minimal
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 
---
 include/net/netns/ipv6.h |  1 +
 net/ipv6/fib6_rules.c| 34 --
 net/ipv6/route.c |  1 +
 3 files changed, 26 insertions(+), 10 deletions(-)

diff --git a/include/net/netns/ipv6.h b/include/net/netns/ipv6.h
index abdf3b40303b..0e50bf3ed097 100644
--- a/include/net/netns/ipv6.h
+++ b/include/net/netns/ipv6.h
@@ -65,6 +65,7 @@ struct netns_ipv6 {
unsigned int ip6_rt_gc_expire;
unsigned longip6_rt_last_gc;
 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
+   bool fib6_has_custom_rules;
struct rt6_info *ip6_prohibit_entry;
struct rt6_info *ip6_blk_hole_entry;
struct fib6_table   *fib6_local_tbl;
diff --git a/net/ipv6/fib6_rules.c b/net/ipv6/fib6_rules.c
index 2f29e4e33bd3..693c27ede40e 100644
--- a/net/ipv6/fib6_rules.c
+++ b/net/ipv6/fib6_rules.c
@@ -63,19 +63,32 @@ unsigned int fib6_rules_seq_read(struct net *net)
 struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
   int flags, pol_lookup_t lookup)
 {
-   struct fib_lookup_arg arg = {
-   .lookup_ptr = lookup,
-   .flags = FIB_LOOKUP_NOREF,
-   };
-
/* update flow if oif or iif point to device enslaved to l3mdev */