forked from luck/tmp_suning_uos_patched
81c3d5470e
Arnaldo and I agreed it could be applied now, because I have other pending patches depending on this one (Thank you Arnaldo) (The other important patch moves skc_refcnt in a separate cache line, so that the SMP/NUMA performance doesnt suffer from cache line ping pongs) 1) First some performance data : -------------------------------- tcp_v4_rcv() wastes a *lot* of time in __inet_lookup_established() The most time critical code is : sk_for_each(sk, node, &head->chain) { if (INET_MATCH(sk, acookie, saddr, daddr, ports, dif)) goto hit; /* You sunk my battleship! */ } The sk_for_each() does use prefetch() hints but only the begining of "struct sock" is prefetched. As INET_MATCH first comparison uses inet_sk(__sk)->daddr, wich is far away from the begining of "struct sock", it has to bring into CPU cache cold cache line. Each iteration has to use at least 2 cache lines. This can be problematic if some chains are very long. 2) The goal ----------- The idea I had is to change things so that INET_MATCH() may return FALSE in 99% of cases only using the data already in the CPU cache, using one cache line per iteration. 3) Description of the patch --------------------------- Adds a new 'unsigned int skc_hash' field in 'struct sock_common', filling a 32 bits hole on 64 bits platform. struct sock_common { unsigned short skc_family; volatile unsigned char skc_state; unsigned char skc_reuse; int skc_bound_dev_if; struct hlist_node skc_node; struct hlist_node skc_bind_node; atomic_t skc_refcnt; + unsigned int skc_hash; struct proto *skc_prot; }; Store in this 32 bits field the full hash, not masked by (ehash_size - 1) Using this full hash as the first comparison done in INET_MATCH permits us immediatly skip the element without touching a second cache line in case of a miss. Suppress the sk_hashent/tw_hashent fields since skc_hash (aliased to sk_hash and tw_hash) already contains the slot number if we mask with (ehash_size - 1) File include/net/inet_hashtables.h 64 bits platforms : #define INET_MATCH(__sk, __hash, __cookie, __saddr, __daddr, __ports, __dif)\ (((__sk)->sk_hash == (__hash)) ((*((__u64 *)&(inet_sk(__sk)->daddr)))== (__cookie)) && \ ((*((__u32 *)&(inet_sk(__sk)->dport))) == (__ports)) && \ (!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif)))) 32bits platforms: #define TCP_IPV4_MATCH(__sk, __hash, __cookie, __saddr, __daddr, __ports, __dif)\ (((__sk)->sk_hash == (__hash)) && \ (inet_sk(__sk)->daddr == (__saddr)) && \ (inet_sk(__sk)->rcv_saddr == (__daddr)) && \ (!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif)))) - Adds a prefetch(head->chain.first) in __inet_lookup_established()/__tcp_v4_check_established() and __inet6_lookup_established()/__tcp_v6_check_established() and __dccp_v4_check_established() to bring into cache the first element of the list, before the {read|write}_lock(&head->lock); Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Acked-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: David S. Miller <davem@davemloft.net> |
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.. | ||
bluetooth | ||
irda | ||
sctp | ||
tc_act | ||
act_api.h | ||
act_generic.h | ||
addrconf.h | ||
af_unix.h | ||
ah.h | ||
arp.h | ||
atmclip.h | ||
ax25.h | ||
checksum.h | ||
compat.h | ||
datalink.h | ||
dn_dev.h | ||
dn_fib.h | ||
dn_neigh.h | ||
dn_nsp.h | ||
dn_route.h | ||
dn.h | ||
dsfield.h | ||
dst.h | ||
esp.h | ||
flow.h | ||
gen_stats.h | ||
icmp.h | ||
ieee80211_crypt.h | ||
ieee80211.h | ||
if_inet6.h | ||
inet6_hashtables.h | ||
inet_common.h | ||
inet_connection_sock.h | ||
inet_ecn.h | ||
inet_hashtables.h | ||
inet_timewait_sock.h | ||
inetpeer.h | ||
ip6_checksum.h | ||
ip6_fib.h | ||
ip6_route.h | ||
ip6_tunnel.h | ||
ip_fib.h | ||
ip_mp_alg.h | ||
ip_vs.h | ||
ip.h | ||
ipcomp.h | ||
ipconfig.h | ||
ipip.h | ||
ipv6.h | ||
ipx.h | ||
iw_handler.h | ||
lapb.h | ||
llc_c_ac.h | ||
llc_c_ev.h | ||
llc_c_st.h | ||
llc_conn.h | ||
llc_if.h | ||
llc_pdu.h | ||
llc_s_ac.h | ||
llc_s_ev.h | ||
llc_s_st.h | ||
llc_sap.h | ||
llc.h | ||
ndisc.h | ||
neighbour.h | ||
netrom.h | ||
p8022.h | ||
pkt_act.h | ||
pkt_cls.h | ||
pkt_sched.h | ||
protocol.h | ||
psnap.h | ||
raw.h | ||
rawv6.h | ||
request_sock.h | ||
rose.h | ||
route.h | ||
sch_generic.h | ||
scm.h | ||
slhc_vj.h | ||
snmp.h | ||
sock.h | ||
syncppp.h | ||
tcp_ecn.h | ||
tcp_states.h | ||
tcp.h | ||
transp_v6.h | ||
udp.h | ||
x25.h | ||
x25device.h | ||
xfrm.h |