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: add 9P2000.L rename operation
2010-05-21 16:44:34 -05:00
Bluetooth: Create per controller workqueue
2010-05-10 09:34:03 +02:00
caif: Bugfix - use standard Linux lists
2010-05-23 23:57:41 -07:00
tree-wide: fix typos "ass?o[sc]iac?te" -> "associate" in comments
2010-02-15 15:38:10 +01:00
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
net: CONFIG_NET_NS reduction
2010-06-02 05:16:23 -07:00
ipv6: ip6mr: support multiple tables
2010-05-11 14:40:55 +02:00
Phonet: zero-copy GPRS TX
2010-01-07 00:24:55 -08:00
net: use __packed annotation
2010-06-03 03:21:52 -07:00
pkt_sched: skbedit add support for setting mark
2009-10-22 21:56:42 -07:00
tipc: Update commenting in TIPC API
2010-05-12 23:02:23 -07:00
net: restore gnet_stats_basic to previous definition
2009-08-17 21:33:49 -07:00
net: Add checking to rcu_dereference() primitives
2010-02-25 09:41:03 +01:00
af_ieee802154: add support for WANT_ACK socket option
2009-08-12 21:54:50 -07:00
net: sock_def_readable() and friends RCU conversion
2010-05-01 15:00:15 -07:00
net: cleanup include/net
2009-11-04 05:06:25 -08:00
net: make neigh_ops constant
2009-09-01 17:40:57 -07:00
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
net: CONFIG_NET_NS reduction
2010-06-02 05:16:23 -07:00
cls_cgroup: Initialise classid when module is absent
2010-05-25 18:53:57 -07:00
net: fix compat_sys_recvmmsg parameter type
2009-12-11 15:07:56 -08:00
dcbnl: Add support for setapp/getapp to netdev dcbnl_rtnl_ops
2009-09-01 01:24:30 -07:00
net: use __packed annotation
2010-06-03 03:21:52 -07:00
decnet: Remove unused FIB metric macros.
2010-03-27 19:23:46 -07:00
net: use __packed annotation
2010-06-03 03:21:52 -07:00
net: check for refcount if pop a stacked dst_entry
2010-06-04 15:56:00 -07:00
netns: embed ip6_dst_ops directly
2009-09-01 17:40:31 -07:00
net: fib_rules: mark arguments to fib_rules_register const and __net_initdata
2010-04-26 16:02:04 +02:00
flow: virtualize flow cache entry methods
2010-04-07 03:43:18 -07:00
net: cleanup include/net
2009-11-04 05:06:25 -08:00
net: CONFIG_NET_NS reduction
2010-06-02 05:16:23 -07:00
ipv4: raw: move struct raw_sock and raw_sk() to include/net/raw.h
2010-04-13 14:49:31 -07:00
wireless: update radiotap parser
2010-02-08 16:50:53 -05:00
ieee802154: move headers out of extra directory
2009-07-23 17:08:51 +04:00
ieee802154: add an mlme_ops call to retrieve PHY object
2009-11-06 14:32:18 +03:00
ipv6: Replace inet6_ifaddr->dead with state
2010-05-18 15:36:06 -07:00
net: replace ipfragok with skb->local_df
2010-04-15 23:36:37 -07:00
tcp: Fix a connect() race with timewait sockets
2009-12-08 20:17:51 -08:00
net: replace ipfragok with skb->local_df
2010-04-15 23:36:37 -07:00
tcp: Fix a connect() race with timewait sockets
2009-12-08 20:17:51 -08:00
net: Make RFS socket operations not be inet specific.
2010-04-27 15:11:48 -07:00
net: suppress RCU lockdep false positive in twsk_net()
2010-04-27 12:39:01 -07:00
inetpeer: Optimize inet_getid()
2009-11-13 20:46:58 -08:00
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
ipv6 fib: Make rt6_info{} more cache-line aware.
2010-04-01 18:41:41 -07:00
net: sk_dst_cache RCUification
2010-04-13 01:41:33 -07:00
net: use __packed annotation
2010-06-03 03:21:52 -07:00
Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6
2009-11-06 00:55:55 -08:00
ipvs: SCTP Trasport Loadbalancing Support
2010-02-18 12:31:05 +01:00
percpu: add __percpu sparse annotations to net
2010-02-16 23:05:38 -08:00
net: cleanup include/net
2009-11-04 05:06:25 -08:00
ipv6: Refactor update of IPv6 flowi destination address for srcrt (RH) option
2010-06-02 07:08:31 -07:00
net: use __packed annotation
2010-06-03 03:21:52 -07:00
include/net/iw_handler.h: Use SIOCIWFIRST not SIOCSIWCOMMIT in comment
2010-03-31 14:49:12 -04:00
llc: convert llc_sap_list to RCU
2009-12-26 20:46:28 -08:00
llc: use a device based hash table to speed up multicast delivery
2009-12-26 20:43:57 -08:00
wireless: fix mac80211.h kernel-doc warnings
2010-05-24 15:07:42 -04:00
net: use __packed annotation
2010-06-03 03:21:52 -07:00
ipv6 mcast: Introduce include/net/mld.h for MLD definitions.
2010-04-23 13:35:55 +09:00
net: use __packed annotation
2010-06-03 03:21:52 -07:00
netfilter: bridge-netfilter: Fix MAC header handling with IP DNAT
2010-04-15 12:26:39 +02:00
nsproxy: remove INIT_NSPROXY()
2010-03-12 15:52:40 -08:00
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: fix unaligned access in nla_get_be64()
2010-03-19 22:47:23 -07:00
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
ieee802154: add support for channel pages from IEEE 802.15.4-2006
2009-08-19 23:08:22 +04:00
net: rename skb->iif to skb->skb_iif
2009-11-20 15:35:04 -08:00
net: Define accessors to manipulate QDISC_STATE_RUNNING
2010-06-02 03:23:51 -07:00
net: drop capability from protocol definitions
2009-11-05 21:40:17 -08:00
ipv4: ipmr: support multiple tables
2010-04-13 14:49:34 -07:00
ipv6: Use correct data types for ICMPv6 type and code
2009-06-23 04:31:07 -07:00
net: cleanup include/net
2009-11-04 05:06:25 -08:00
cfg80211: add regulatory hint disconnect support
2010-02-01 15:40:06 -05:00
tcp: account SYN-ACK timeouts & retransmissions
2010-01-17 19:09:39 -08:00
NET: ROSE: Don't use static buffer.
2009-07-26 19:11:14 -07:00
net: implements ip_route_input_noref()
2010-05-17 17:18:51 -07:00
rtnetlink: support specifying device flags on device creation
2010-02-27 02:43:40 -08:00
net: add additional lock to qdisc to increase throughput
2010-06-02 05:09:29 -07:00
net: cleanup include/net
2009-11-04 05:06:25 -08:00
tcp: fix outsegs stat for TSO segments
2010-04-22 16:00:00 -07:00
Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6
2010-06-06 17:42:02 -07:00
tcp: Fix slowness in read /proc/net/tcp
2010-06-07 00:43:42 -07:00
IPv6: Add dontfrag argument to relevant functions
2010-04-23 23:35:28 -07:00
udp: bind() optimisation
2009-11-10 20:54:38 -08:00
wext: refactor
2009-10-07 16:39:43 -04:00
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
2009-12-09 19:43:33 -08:00
ieee802154: add support for creation/removal of logic interfaces
2009-11-06 14:32:24 +03:00
X25: Move accept approve flag to bitfield
2010-05-17 17:39:27 -07:00
X25: Add if_x25.h and x25 to device identifiers
2010-04-22 16:12:36 -07:00
Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6
2010-04-11 14:53:53 -07:00
a8b690f98b