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netfilter: conntrack: use siphash_4u64

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This function is used for every packet, siphash_4u64 is noticeably faster
than using local buffer + siphash:

Before:
  1.23%  kpktgend_0       [kernel.vmlinux]     [k] __siphash_unaligned
  0.14%  kpktgend_0       [nf_conntrack]       [k] hash_conntrack_raw
After:
  0.79%  kpktgend_0       [kernel.vmlinux]     [k] siphash_4u64
  0.15%  kpktgend_0       [nf_conntrack]       [k] hash_conntrack_raw

In the pktgen test this gives about ~2.4% performance improvement.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Florian Westphal 2022-11-02 13:46:33 +01:00 committed by Pablo Neira Ayuso
parent 971095c6fa
commit d2c806abcf
1 changed files with 13 additions and 17 deletions
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30
net/netfilter/nf_conntrack_core.c
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@ -211,28 +211,24 @@ static u32 hash_conntrack_raw(const struct nf_conntrack_tuple *tuple,
unsigned int zoneid,
const struct net *net)
{
struct {
struct nf_conntrack_man src;
union nf_inet_addr dst_addr;
unsigned int zone;
u32 net_mix;
u16 dport;
u16 proto;
} __aligned(SIPHASH_ALIGNMENT) combined;
u64 a, b, c, d;
get_random_once(&nf_conntrack_hash_rnd, sizeof(nf_conntrack_hash_rnd));
memset(&combined, 0, sizeof(combined));
/* The direction must be ignored, handle usable tuplehash members manually */
a = (u64)tuple->src.u3.all[0] << 32 | tuple->src.u3.all[3];
b = (u64)tuple->dst.u3.all[0] << 32 | tuple->dst.u3.all[3];
/* The direction must be ignored, so handle usable members manually. */
combined.src = tuple->src;
combined.dst_addr = tuple->dst.u3;
combined.zone = zoneid;
combined.net_mix = net_hash_mix(net);
combined.dport = (__force __u16)tuple->dst.u.all;
combined.proto = tuple->dst.protonum;
c = (__force u64)tuple->src.u.all << 32 | (__force u64)tuple->dst.u.all << 16;
c |= tuple->dst.protonum;
return (u32)siphash(&combined, sizeof(combined), &nf_conntrack_hash_rnd);
d = (u64)zoneid << 32 | net_hash_mix(net);
/* IPv4: u3.all[1,2,3] == 0 */
c ^= (u64)tuple->src.u3.all[1] << 32 | tuple->src.u3.all[2];
d += (u64)tuple->dst.u3.all[1] << 32 | tuple->dst.u3.all[2];
return (u32)siphash_4u64(a, b, c, d, &nf_conntrack_hash_rnd);
}
static u32 scale_hash(u32 hash)