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SubjectRe: [PATCH v2 net-next 2/2] ipv6: fib6: avoid indirect calls from fib6_rule_lookup
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On Tue, 2020-06-23 at 09:42 -0700, Brian Vazquez wrote:
> It was reported that a considerable amount of cycles were spent on the
> expensive indirect calls on fib6_rule_lookup. This patch introduces an
> inline helper called pol_route_func that uses the indirect_call_wrappers
> to avoid the indirect calls.
>
> This patch saves around 50ns per call.
>
> Performance was measured on the receiver by checking the amount of
> syncookies that server was able to generate under a synflood load.
>
> Traffic was generated using trafgen[1] which was pushing around 1Mpps on
> a single queue. Receiver was using only one rx queue which help to
> create a bottle neck and make the experiment rx-bounded.
>
> These are the syncookies generated over 10s from the different runs:
>
> Whithout the patch:
> TcpExtSyncookiesSent 3553749 0.0
> TcpExtSyncookiesSent 3550895 0.0
> TcpExtSyncookiesSent 3553845 0.0
> TcpExtSyncookiesSent 3541050 0.0
> TcpExtSyncookiesSent 3539921 0.0
> TcpExtSyncookiesSent 3557659 0.0
> TcpExtSyncookiesSent 3526812 0.0
> TcpExtSyncookiesSent 3536121 0.0
> TcpExtSyncookiesSent 3529963 0.0
> TcpExtSyncookiesSent 3536319 0.0
>
> With the patch:
> TcpExtSyncookiesSent 3611786 0.0
> TcpExtSyncookiesSent 3596682 0.0
> TcpExtSyncookiesSent 3606878 0.0
> TcpExtSyncookiesSent 3599564 0.0
> TcpExtSyncookiesSent 3601304 0.0
> TcpExtSyncookiesSent 3609249 0.0
> TcpExtSyncookiesSent 3617437 0.0
> TcpExtSyncookiesSent 3608765 0.0
> TcpExtSyncookiesSent 3620205 0.0
> TcpExtSyncookiesSent 3601895 0.0
>
> Without the patch the average is 354263 pkt/s or 2822 ns/pkt and with
> the patch the average is 360738 pkt/s or 2772 ns/pkt which gives an
> estimate of 50 ns per packet.
>
> [1] http://netsniff-ng.org/
>
> Changelog since v1:
> - Change ordering in the ICW (Paolo Abeni)
>
> Cc: Luigi Rizzo <lrizzo@google.com>
> Cc: Paolo Abeni <pabeni@redhat.com>
> Reported-by: Eric Dumazet <edumazet@google.com>
> Signed-off-by: Brian Vazquez <brianvv@google.com>
> ---
> include/net/ip6_fib.h | 36 ++++++++++++++++++++++++++++++++++++
> net/ipv6/fib6_rules.c | 9 ++++++---
> net/ipv6/ip6_fib.c | 3 ++-
> net/ipv6/route.c | 8 ++++----
> 4 files changed, 48 insertions(+), 8 deletions(-)
>
> diff --git a/include/net/ip6_fib.h b/include/net/ip6_fib.h
> index 3f615a29766e..cc8356fd927f 100644
> --- a/include/net/ip6_fib.h
> +++ b/include/net/ip6_fib.h
> @@ -19,6 +19,7 @@
> #include <net/netlink.h>
> #include <net/inetpeer.h>
> #include <net/fib_notifier.h>
> +#include <linux/indirect_call_wrapper.h>
>
> #ifdef CONFIG_IPV6_MULTIPLE_TABLES
> #define FIB6_TABLE_HASHSZ 256
> @@ -552,6 +553,41 @@ struct bpf_iter__ipv6_route {
> };
> #endif
>
> +INDIRECT_CALLABLE_DECLARE(struct rt6_info *ip6_pol_route_output(struct net *net,
> + struct fib6_table *table,
> + struct flowi6 *fl6,
> + const struct sk_buff *skb,
> + int flags));
> +INDIRECT_CALLABLE_DECLARE(struct rt6_info *ip6_pol_route_input(struct net *net,
> + struct fib6_table *table,
> + struct flowi6 *fl6,
> + const struct sk_buff *skb,
> + int flags));
> +INDIRECT_CALLABLE_DECLARE(struct rt6_info *__ip6_route_redirect(struct net *net,
> + struct fib6_table *table,
> + struct flowi6 *fl6,
> + const struct sk_buff *skb,
> + int flags));
> +INDIRECT_CALLABLE_DECLARE(struct rt6_info *ip6_pol_route_lookup(struct net *net,
> + struct fib6_table *table,
> + struct flowi6 *fl6,
> + const struct sk_buff *skb,
> + int flags));
> +static inline struct rt6_info *pol_lookup_func(pol_lookup_t lookup,
> + struct net *net,
> + struct fib6_table *table,
> + struct flowi6 *fl6,
> + const struct sk_buff *skb,
> + int flags)
> +{
> + return INDIRECT_CALL_4(lookup,
> + ip6_pol_route_output,
> + ip6_pol_route_input,
> + ip6_pol_route_lookup,
> + __ip6_route_redirect,
> + net, table, fl6, skb, flags);
> +}
> +
> #ifdef CONFIG_IPV6_MULTIPLE_TABLES
> static inline bool fib6_has_custom_rules(const struct net *net)
> {
> diff --git a/net/ipv6/fib6_rules.c b/net/ipv6/fib6_rules.c
> index fafe556d21e0..6053ef851555 100644
> --- a/net/ipv6/fib6_rules.c
> +++ b/net/ipv6/fib6_rules.c
> @@ -111,11 +111,13 @@ struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
> } else {
> struct rt6_info *rt;
>
> - rt = lookup(net, net->ipv6.fib6_local_tbl, fl6, skb, flags);
> + rt = pol_lookup_func(lookup,
> + net, net->ipv6.fib6_local_tbl, fl6, skb, flags);
> if (rt != net->ipv6.ip6_null_entry && rt->dst.error != -EAGAIN)
> return &rt->dst;
> ip6_rt_put_flags(rt, flags);
> - rt = lookup(net, net->ipv6.fib6_main_tbl, fl6, skb, flags);
> + rt = pol_lookup_func(lookup,
> + net, net->ipv6.fib6_main_tbl, fl6, skb, flags);
> if (rt->dst.error != -EAGAIN)
> return &rt->dst;
> ip6_rt_put_flags(rt, flags);
> @@ -226,7 +228,8 @@ static int __fib6_rule_action(struct fib_rule *rule, struct flowi *flp,
> goto out;
> }
>
> - rt = lookup(net, table, flp6, arg->lookup_data, flags);
> + rt = pol_lookup_func(lookup,
> + net, table, flp6, arg->lookup_data, flags);
> if (rt != net->ipv6.ip6_null_entry) {
> err = fib6_rule_saddr(net, rule, flags, flp6,
> ip6_dst_idev(&rt->dst)->dev);
> diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
> index 49ee89bbcba0..25a90f3f705c 100644
> --- a/net/ipv6/ip6_fib.c
> +++ b/net/ipv6/ip6_fib.c
> @@ -314,7 +314,8 @@ struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
> {
> struct rt6_info *rt;
>
> - rt = lookup(net, net->ipv6.fib6_main_tbl, fl6, skb, flags);
> + rt = pol_lookup_func(lookup,
> + net, net->ipv6.fib6_main_tbl, fl6, skb, flags);
> if (rt->dst.error == -EAGAIN) {
> ip6_rt_put_flags(rt, flags);
> rt = net->ipv6.ip6_null_entry;
> diff --git a/net/ipv6/route.c b/net/ipv6/route.c
> index 82cbb46a2a4f..5852039ca9cf 100644
> --- a/net/ipv6/route.c
> +++ b/net/ipv6/route.c
> @@ -1207,7 +1207,7 @@ static struct rt6_info *ip6_create_rt_rcu(const struct fib6_result *res)
> return nrt;
> }
>
> -static struct rt6_info *ip6_pol_route_lookup(struct net *net,
> +INDIRECT_CALLABLE_SCOPE struct rt6_info *ip6_pol_route_lookup(struct net *net,
> struct fib6_table *table,
> struct flowi6 *fl6,
> const struct sk_buff *skb,
> @@ -2274,7 +2274,7 @@ struct rt6_info *ip6_pol_route(struct net *net, struct fib6_table *table,
> }
> EXPORT_SYMBOL_GPL(ip6_pol_route);
>
> -static struct rt6_info *ip6_pol_route_input(struct net *net,
> +INDIRECT_CALLABLE_SCOPE struct rt6_info *ip6_pol_route_input(struct net *net,
> struct fib6_table *table,
> struct flowi6 *fl6,
> const struct sk_buff *skb,
> @@ -2465,7 +2465,7 @@ void ip6_route_input(struct sk_buff *skb)
> &fl6, skb, flags));
> }
>
> -static struct rt6_info *ip6_pol_route_output(struct net *net,
> +INDIRECT_CALLABLE_SCOPE struct rt6_info *ip6_pol_route_output(struct net *net,
> struct fib6_table *table,
> struct flowi6 *fl6,
> const struct sk_buff *skb,
> @@ -2912,7 +2912,7 @@ struct ip6rd_flowi {
> struct in6_addr gateway;
> };
>
> -static struct rt6_info *__ip6_route_redirect(struct net *net,
> +INDIRECT_CALLABLE_SCOPE struct rt6_info *__ip6_route_redirect(struct net *net,
> struct fib6_table *table,
> struct flowi6 *fl6,
> const struct sk_buff *skb,

Acked-by: Paolo Abeni <pabeni@redhat.com>

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