Fabian Hugelshofer wrote:
Patrick McHardy wrote:
Callgraph information would be useful since its unclear whether
this is the memcpy triggered by netlink message trimming in
af_netlink.c or something different. Unfortunately according
to the documentation this is only supported on x86. I think
selecting the netfilter options as modules should provide
slightly more detail though.
[...]
memcpy is mostly invoked by skb_copy and netlink_broadcast (af_netlink).
netlink_broadcast is expensive on its own and calls pskb_expand_head
which is expensive as well. Using multipart messages would reduce the
need to call netlink_broadcast.
I profiled again with nfnetlink and nf_conntrack compiled as modules:
103599 61.1842 vmlinux
24481 14.4582 ath_pci
19232 11.3582 nf_conntrack
10435 6.1628 wlan
3588 2.1190 nf_conntrack_netlink
2869 1.6944 oprofiled
1886 1.1138 nf_conntrack_ipv4
1447 0.8546 ath_rate_minstrel
627 0.3703 nfnetlink
237 0.1400 ld-uClibc-0.9.29.so
233 0.1376 libuClibc-0.9.29.so
183 0.1081 iptable_raw
174 0.1028 ctevtest
147 0.0868 busybox
85 0.0502 libnfnetlink.so.0.2.0
60 0.0354 libnetfilter_conntrack.so.1.2.0
38 0.0224 arp_tables
2 0.0012 arptable_filter
Again most of the time is spent in the kernel. Memory and skb operations
are accounted there. I suspect that they cause the most overhead.
Do you plan to dig deeper into optimising the non-optimal parts? I
consider myself not to have enough understanding to do it myself.
--
To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
