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Date: Mon, 03 Mar 2014 14:44:16 +0100
From: Jesper Dangaard Brouer <brouer@...hat.com>
To: netfilter-devel@...r.kernel.org,
Eric Dumazet <eric.dumazet@...il.com>,
Pablo Neira Ayuso <pablo@...filter.org>
Cc: Jesper Dangaard Brouer <brouer@...hat.com>, netdev@...r.kernel.org,
"David S. Miller" <davem@...emloft.net>,
Florian Westphal <fw@...len.de>,
"Patrick McHardy" <kaber@...sh.net>
Subject: [nf-next PATCH V3 0/5] netfilter: conntrack: optimization,
remove central spinlock
This patchset change the conntrack locking and provides a huge
performance improvements.
This patchset is based upon Eric Dumazet's proposed patch:
http://thread.gmane.org/gmane.linux.network/268758/focus=47306
I have in agreement with Eric Dumazet, taken over this patch (and
turned it into a entire patchset).
Primary focus is to remove the central spinlock nf_conntrack_lock.
This requires several steps to be acheived.
Patch01: Trivial cleanups
Patch02: Moves the "special" dying/unconfirmed/template lists to use a
per cpu spinlock.
Patch03: Is preparing for patch04, as it address a race
condition. Doing this a seperate patch for reviewers sake.
Patch04: Seperates expect locking from nf_conntrack_lock. The expect
list is small (default max 256), this it just get a single lock.
Patch05: Finally can remove nf_conntrack_lock, and instead uses an
array of hashed spinlocks to protect insertions/deletions of
conntracks into the hash table. While still allowing dynamic
resizing of the hash table.
Testing
-------
For expectations I've mostly tested the FTP nf_conntrack_ftp
helper module, by commands:
for x in `seq 1 300`; do \
echo $x; \
echo -e "USER anonymous\nPASS nothing\nPASV" | nc 192.168.42.129 21; \
done
wget ftp://192.168.42.129/pub/delete.me.4k -O /dev/null
For overload/DoS testing, I've primarily done, SYN-flood attack testing.
Results on a 24-core E5-2695v2(ES) with 10Gbit/s ixgbe (with tool trafgen)
Base kernel : New 810.405 conntrack/sec
Fixed kernel: New 2.233.876 conntrack/sec
Notice other floods attack (SYN+ACK or ACK) can easily be deflected using:
# iptables -A INPUT -m state --state INVALID -j DROP
# sysctl -w net/netfilter/nf_conntrack_tcp_loose=0
E.g. this machine can reflect 6.481.463 "invalid" conntrack/sec (from
an ACK-flood).
Perf data:
----------
The nf_conntrack_lock is suffers from huge contention on current
generation servers (8 or more core/threads). Data from under
SYN-flooding (without a listen socket)
Perf locking congestion is very "visible" on a base kernel:
- 72.56% ksoftirqd/6 [kernel.kallsyms] [k] _raw_spin_lock_bh
- _raw_spin_lock_bh
+ 25.33% init_conntrack
+ 24.86% nf_ct_delete_from_lists
+ 24.62% __nf_conntrack_confirm
+ 24.38% destroy_conntrack
+ 0.70% tcp_packet
+ 2.21% ksoftirqd/6 [kernel.kallsyms] [k] fib_table_lookup
+ 1.15% ksoftirqd/6 [kernel.kallsyms] [k] __slab_free
+ 0.77% ksoftirqd/6 [kernel.kallsyms] [k] inet_getpeer
+ 0.70% ksoftirqd/6 [nf_conntrack] [k] nf_ct_delete
+ 0.55% ksoftirqd/6 [ip_tables] [k] ipt_do_table
Perf after the patchset (SYN-flood attack):
+ 9.62% ksoftirqd/6 [kernel.kallsyms] [k] fib_table_lookup
+ 3.78% ksoftirqd/6 [kernel.kallsyms] [k] __slab_free
+ 2.71% ksoftirqd/6 [kernel.kallsyms] [k] inet_getpeer
+ 2.55% ksoftirqd/6 [kernel.kallsyms] [k] check_leaf
+ 2.38% ksoftirqd/6 [ip_tables] [k] ipt_do_table
+ 2.06% ksoftirqd/6 [kernel.kallsyms] [k] __slab_alloc
+ 1.94% ksoftirqd/6 [nf_conntrack] [k] __nf_conntrack_alloc
- 1.94% ksoftirqd/6 [kernel.kallsyms] [k] _raw_spin_lock
- _raw_spin_lock
+ 90.32% nf_conntrack_double_lock
+ 3.61% get_partial_node
+ 1.81% nf_ct_delete_from_lists
+ 1.68% __nf_conntrack_confirm
+ 1.03% sch_direct_xmit
+ 0.52% scheduler_tick
+ 1.86% ksoftirqd/6 [kernel.kallsyms] [k] nf_iterate
+ 1.80% ksoftirqd/6 [nf_conntrack] [k] init_conntrack
+ 1.77% ksoftirqd/6 [kernel.kallsyms] [k] __neigh_event_send
- 1.70% ksoftirqd/6 [kernel.kallsyms] [k] _raw_spin_lock_bh
- _raw_spin_lock_bh
+ 32.55% nf_ct_del_from_dying_or_unconfirmed_list
+ 25.33% init_conntrack
+ 19.88% tcp_packet
+ 17.97% nf_ct_delete_from_lists
+ 1.62% nf_conntrack_in
+ 1.33% ixgbe_poll
+ 0.74% destroy_conntrack
+ 1.64% ksoftirqd/6 [nf_conntrack] [k] hash_conntrack_raw
+ 1.58% ksoftirqd/6 [kernel.kallsyms] [k] __netif_receive_skb_core
+ 1.51% ksoftirqd/6 [nf_conntrack] [k] __nf_conntrack_find_get
+ 1.48% ksoftirqd/6 [kernel.kallsyms] [k] __cmpxchg_double_slab
+ 1.46% ksoftirqd/6 [nf_conntrack] [k] nf_conntrack_in
+ 1.45% ksoftirqd/6 [kernel.kallsyms] [k] __local_bh_enable_ip
---
Jesper Dangaard Brouer (5):
netfilter: conntrack: remove central spinlock nf_conntrack_lock
netfilter: conntrack: seperate expect locking from nf_conntrack_lock
netfilter: avoid race with exp->master ct
netfilter: conntrack: spinlock per cpu to protect special lists.
netfilter: trivial code cleanup and doc changes
include/net/netfilter/nf_conntrack.h | 11 +
include/net/netfilter/nf_conntrack_core.h | 9 +
include/net/netns/conntrack.h | 13 +
net/netfilter/nf_conntrack_core.c | 432 ++++++++++++++++++++---------
net/netfilter/nf_conntrack_expect.c | 36 ++
net/netfilter/nf_conntrack_h323_main.c | 4
net/netfilter/nf_conntrack_helper.c | 41 ++-
net/netfilter/nf_conntrack_netlink.c | 128 +++++----
net/netfilter/nf_conntrack_sip.c | 8 -
9 files changed, 461 insertions(+), 221 deletions(-)
--
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