Three types of data need to be protected in the case of the hash types:
a. The hash buckets: standard rcu pointer operations are used.
b. The element blobs in the hash buckets are stored in an array and
a bitmap is used for book-keeping to tell which elements in the array
are used or free.
c. Networks per cidr values and the cidr values themselves are stored
in fix sized arrays and need no protection. The values are modified
in such an order that in the worst case an element testing is repeated
once with the same cidr value.
The ipset hash approach uses arrays instead of lists and therefore is
incompatible with rhashtable.
Performance is tested by Jesper Dangaard Brouer:
Simple drop in FORWARD
~~~~~~~~~~~~~~~~~~~~~~
Dropping via simple iptables net-mask match::
iptables -t raw -N simple || iptables -t raw -F simple
iptables -t raw -I simple -s 198.18.0.0/15 -j DROP
iptables -t raw -D PREROUTING -j simple
iptables -t raw -I PREROUTING -j simple
Drop performance in "raw": 11.3Mpps
Generator: sending 12.2Mpps (tx:12264083 pps)
Drop via original ipset in RAW table
~~~~~~~~~~~~~~~~~~~~~~~~~~~
Create a set with lots of elements::
sudo ./ipset destroy test
echo "create test hash:ip hashsize 65536" > test.set
for x in `seq 0 255`; do
for y in `seq 0 255`; do
echo "add test 198.18.$x.$y" >> test.set
done
done
sudo ./ipset restore < test.set
Dropping via ipset::
iptables -t raw -F
iptables -t raw -N net198 || iptables -t raw -F net198
iptables -t raw -I net198 -m set --match-set test src -j DROP
iptables -t raw -I PREROUTING -j net198
Drop performance in "raw" with ipset: 8Mpps
Perf report numbers ipset drop in "raw"::
+ 24.65% ksoftirqd/1 [ip_set] [k] ip_set_test
- 21.42% ksoftirqd/1 [kernel.kallsyms] [k] _raw_read_lock_bh
- _raw_read_lock_bh
+ 99.88% ip_set_test
- 19.42% ksoftirqd/1 [kernel.kallsyms] [k] _raw_read_unlock_bh
- _raw_read_unlock_bh
+ 99.72% ip_set_test
+ 4.31% ksoftirqd/1 [ip_set_hash_ip] [k] hash_ip4_kadt
+ 2.27% ksoftirqd/1 [ixgbe] [k] ixgbe_fetch_rx_buffer
+ 2.18% ksoftirqd/1 [ip_tables] [k] ipt_do_table
+ 1.81% ksoftirqd/1 [ip_set_hash_ip] [k] hash_ip4_test
+ 1.61% ksoftirqd/1 [kernel.kallsyms] [k] __netif_receive_skb_core
+ 1.44% ksoftirqd/1 [kernel.kallsyms] [k] build_skb
+ 1.42% ksoftirqd/1 [kernel.kallsyms] [k] ip_rcv
+ 1.36% ksoftirqd/1 [kernel.kallsyms] [k] __local_bh_enable_ip
+ 1.16% ksoftirqd/1 [kernel.kallsyms] [k] dev_gro_receive
+ 1.09% ksoftirqd/1 [kernel.kallsyms] [k] __rcu_read_unlock
+ 0.96% ksoftirqd/1 [ixgbe] [k] ixgbe_clean_rx_irq
+ 0.95% ksoftirqd/1 [kernel.kallsyms] [k] __netdev_alloc_frag
+ 0.88% ksoftirqd/1 [kernel.kallsyms] [k] kmem_cache_alloc
+ 0.87% ksoftirqd/1 [xt_set] [k] set_match_v3
+ 0.85% ksoftirqd/1 [kernel.kallsyms] [k] inet_gro_receive
+ 0.83% ksoftirqd/1 [kernel.kallsyms] [k] nf_iterate
+ 0.76% ksoftirqd/1 [kernel.kallsyms] [k] put_compound_page
+ 0.75% ksoftirqd/1 [kernel.kallsyms] [k] __rcu_read_lock
Drop via ipset in RAW table with RCU-locking
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
With RCU locking, the RW-lock is gone.
Drop performance in "raw" with ipset with RCU-locking: 11.3Mpps
Performance-tested-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
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