android_kernel_motorola_sm6225/include/net
Tom Herbert a8b690f98b tcp: Fix slowness in read /proc/net/tcp
This patch address a serious performance issue in reading the
TCP sockets table (/proc/net/tcp).

Reading the full table is done by a number of sequential read
operations.  At each read operation, a seek is done to find the
last socket that was previously read.  This seek operation requires
that the sockets in the table need to be counted up to the current
file position, and to count each of these requires taking a lock for
each non-empty bucket.  The whole algorithm is O(n^2).

The fix is to cache the last bucket value, offset within the bucket,
and the file position returned by the last read operation.   On the
next sequential read, the bucket and offset are used to find the
last read socket immediately without needing ot scan the previous
buckets  the table.  This algorithm t read the whole table is O(n).

The improvement offered by this patch is easily show by performing
cat'ing /proc/net/tcp on a machine with a lot of connections.  With
about 182K connections in the table, I see the following:

- Without patch
time cat /proc/net/tcp > /dev/null

real	1m56.729s
user	0m0.214s
sys	1m56.344s

- With patch
time cat /proc/net/tcp > /dev/null

real	0m0.894s
user	0m0.290s
sys	0m0.594s

Signed-off-by: Tom Herbert <therbert@google.com>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-07 00:43:42 -07:00
..
9p 9p: add 9P2000.L rename operation 2010-05-21 16:44:34 -05:00
bluetooth Bluetooth: Create per controller workqueue 2010-05-10 09:34:03 +02:00
caif caif: Bugfix - use standard Linux lists 2010-05-23 23:57:41 -07:00
irda tree-wide: fix typos "ass?o[sc]iac?te" -> "associate" in comments 2010-02-15 15:38:10 +01:00
iucv include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
netfilter net: CONFIG_NET_NS reduction 2010-06-02 05:16:23 -07:00
netns ipv6: ip6mr: support multiple tables 2010-05-11 14:40:55 +02:00
phonet Phonet: zero-copy GPRS TX 2010-01-07 00:24:55 -08:00
sctp net: use __packed annotation 2010-06-03 03:21:52 -07:00
tc_act pkt_sched: skbedit add support for setting mark 2009-10-22 21:56:42 -07:00
tipc tipc: Update commenting in TIPC API 2010-05-12 23:02:23 -07:00
act_api.h net: restore gnet_stats_basic to previous definition 2009-08-17 21:33:49 -07:00
addrconf.h net: Add checking to rcu_dereference() primitives 2010-02-25 09:41:03 +01:00
af_ieee802154.h af_ieee802154: add support for WANT_ACK socket option 2009-08-12 21:54:50 -07:00
af_rxrpc.h
af_unix.h net: sock_def_readable() and friends RCU conversion 2010-05-01 15:00:15 -07:00
ah.h net: cleanup include/net 2009-11-04 05:06:25 -08:00
arp.h net: make neigh_ops constant 2009-09-01 17:40:57 -07:00
atmclip.h
ax25.h include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
ax88796.h
cfg80211.h net: CONFIG_NET_NS reduction 2010-06-02 05:16:23 -07:00
checksum.h
cipso_ipv4.h
cls_cgroup.h cls_cgroup: Initialise classid when module is absent 2010-05-25 18:53:57 -07:00
compat.h net: fix compat_sys_recvmmsg parameter type 2009-12-11 15:07:56 -08:00
datalink.h
dcbnl.h dcbnl: Add support for setapp/getapp to netdev dcbnl_rtnl_ops 2009-09-01 01:24:30 -07:00
dn.h
dn_dev.h net: use __packed annotation 2010-06-03 03:21:52 -07:00
dn_fib.h decnet: Remove unused FIB metric macros. 2010-03-27 19:23:46 -07:00
dn_neigh.h
dn_nsp.h net: use __packed annotation 2010-06-03 03:21:52 -07:00
dn_route.h
dsa.h
dsfield.h
dst.h net: check for refcount if pop a stacked dst_entry 2010-06-04 15:56:00 -07:00
dst_ops.h netns: embed ip6_dst_ops directly 2009-09-01 17:40:31 -07:00
esp.h
ethoc.h
fib_rules.h net: fib_rules: mark arguments to fib_rules_register const and __net_initdata 2010-04-26 16:02:04 +02:00
flow.h flow: virtualize flow cache entry methods 2010-04-07 03:43:18 -07:00
garp.h
gen_stats.h net: cleanup include/net 2009-11-04 05:06:25 -08:00
genetlink.h net: CONFIG_NET_NS reduction 2010-06-02 05:16:23 -07:00
icmp.h ipv4: raw: move struct raw_sock and raw_sk() to include/net/raw.h 2010-04-13 14:49:31 -07:00
ieee80211_radiotap.h wireless: update radiotap parser 2010-02-08 16:50:53 -05:00
ieee802154.h
ieee802154_netdev.h ieee802154: add an mlme_ops call to retrieve PHY object 2009-11-06 14:32:18 +03:00
if_inet6.h ipv6: Replace inet6_ifaddr->dead with state 2010-05-18 15:36:06 -07:00
inet6_connection_sock.h net: replace ipfragok with skb->local_df 2010-04-15 23:36:37 -07:00
inet6_hashtables.h tcp: Fix a connect() race with timewait sockets 2009-12-08 20:17:51 -08:00
inet_common.h
inet_connection_sock.h net: replace ipfragok with skb->local_df 2010-04-15 23:36:37 -07:00
inet_ecn.h
inet_frag.h
inet_hashtables.h tcp: Fix a connect() race with timewait sockets 2009-12-08 20:17:51 -08:00
inet_sock.h net: Make RFS socket operations not be inet specific. 2010-04-27 15:11:48 -07:00
inet_timewait_sock.h net: suppress RCU lockdep false positive in twsk_net() 2010-04-27 12:39:01 -07:00
inetpeer.h inetpeer: Optimize inet_getid() 2009-11-13 20:46:58 -08:00
ip.h kernel-wide: replace USHORT_MAX, SHORT_MAX and SHORT_MIN with USHRT_MAX, SHRT_MAX and SHRT_MIN 2010-05-25 08:07:02 -07:00
ip6_checksum.h
ip6_fib.h ipv6 fib: Make rt6_info{} more cache-line aware. 2010-04-01 18:41:41 -07:00
ip6_route.h net: sk_dst_cache RCUification 2010-04-13 01:41:33 -07:00
ip6_tunnel.h net: use __packed annotation 2010-06-03 03:21:52 -07:00
ip_fib.h Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 2009-11-06 00:55:55 -08:00
ip_vs.h ipvs: SCTP Trasport Loadbalancing Support 2010-02-18 12:31:05 +01:00
ipcomp.h percpu: add __percpu sparse annotations to net 2010-02-16 23:05:38 -08:00
ipconfig.h
ipip.h net: cleanup include/net 2009-11-04 05:06:25 -08:00
ipv6.h ipv6: Refactor update of IPv6 flowi destination address for srcrt (RH) option 2010-06-02 07:08:31 -07:00
ipx.h net: use __packed annotation 2010-06-03 03:21:52 -07:00
iw_handler.h include/net/iw_handler.h: Use SIOCIWFIRST not SIOCSIWCOMMIT in comment 2010-03-31 14:49:12 -04:00
lapb.h
lib80211.h
llc.h llc: convert llc_sap_list to RCU 2009-12-26 20:46:28 -08:00
llc_c_ac.h
llc_c_ev.h
llc_c_st.h
llc_conn.h llc: use a device based hash table to speed up multicast delivery 2009-12-26 20:43:57 -08:00
llc_if.h
llc_pdu.h
llc_s_ac.h
llc_s_ev.h
llc_s_st.h
llc_sap.h
mac80211.h wireless: fix mac80211.h kernel-doc warnings 2010-05-24 15:07:42 -04:00
mip6.h net: use __packed annotation 2010-06-03 03:21:52 -07:00
mld.h ipv6 mcast: Introduce include/net/mld.h for MLD definitions. 2010-04-23 13:35:55 +09:00
ndisc.h net: use __packed annotation 2010-06-03 03:21:52 -07:00
neighbour.h netfilter: bridge-netfilter: Fix MAC header handling with IP DNAT 2010-04-15 12:26:39 +02:00
net_namespace.h nsproxy: remove INIT_NSPROXY() 2010-03-12 15:52:40 -08:00
netdma.h
netevent.h
netlabel.h include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
netlink.h netlink: fix unaligned access in nla_get_be64() 2010-03-19 22:47:23 -07:00
netrom.h include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
nexthop.h
nl802154.h ieee802154: add support for channel pages from IEEE 802.15.4-2006 2009-08-19 23:08:22 +04:00
p8022.h
pkt_cls.h net: rename skb->iif to skb->skb_iif 2009-11-20 15:35:04 -08:00
pkt_sched.h net: Define accessors to manipulate QDISC_STATE_RUNNING 2010-06-02 03:23:51 -07:00
protocol.h net: drop capability from protocol definitions 2009-11-05 21:40:17 -08:00
psnap.h
raw.h ipv4: ipmr: support multiple tables 2010-04-13 14:49:34 -07:00
rawv6.h
red.h net: cleanup include/net 2009-11-04 05:06:25 -08:00
regulatory.h cfg80211: add regulatory hint disconnect support 2010-02-01 15:40:06 -05:00
request_sock.h tcp: account SYN-ACK timeouts & retransmissions 2010-01-17 19:09:39 -08:00
rose.h NET: ROSE: Don't use static buffer. 2009-07-26 19:11:14 -07:00
route.h net: implements ip_route_input_noref() 2010-05-17 17:18:51 -07:00
rtnetlink.h rtnetlink: support specifying device flags on device creation 2010-02-27 02:43:40 -08:00
sch_generic.h net: add additional lock to qdisc to increase throughput 2010-06-02 05:09:29 -07:00
scm.h net: cleanup include/net 2009-11-04 05:06:25 -08:00
slhc_vj.h
snmp.h tcp: fix outsegs stat for TSO segments 2010-04-22 16:00:00 -07:00
sock.h Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 2010-06-06 17:42:02 -07:00
stp.h
tcp.h tcp: Fix slowness in read /proc/net/tcp 2010-06-07 00:43:42 -07:00
tcp_states.h
timewait_sock.h
transp_v6.h IPv6: Add dontfrag argument to relevant functions 2010-04-23 23:35:28 -07:00
udp.h udp: bind() optimisation 2009-11-10 20:54:38 -08:00
udplite.h
wext.h wext: refactor 2009-10-07 16:39:43 -04:00
wimax.h Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2009-12-09 19:43:33 -08:00
wpan-phy.h ieee802154: add support for creation/removal of logic interfaces 2009-11-06 14:32:24 +03:00
x25.h X25: Move accept approve flag to bitfield 2010-05-17 17:39:27 -07:00
x25device.h X25: Add if_x25.h and x25 to device identifiers 2010-04-22 16:12:36 -07:00
xfrm.h Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 2010-04-11 14:53:53 -07:00