On Fri, 10 Apr 2009, David Miller wrote: > > [ CC:'ing netfilter-devel and netdev... ] I wonder if we should bring in the RCU people too, for them to tell you that the networking people are beign silly, and should not synchronize with the very heavy-handed synchronize_net() but instead of doing synchronization (which is probably why adding a few hundred rules then takes several seconds - each synchronizes and that takes a timer tick or so), add the rules to be free'd on some rcu-freeing list for later freeing. Or whatever. Paul? synchronize_net() just calls synchronize_rcu(), and with that knowledge and a simple git show 784544739a25c30637397ace5489eeb6e15d7d49 I bet you can already tell people how to fix their performance issue. Linus --- > > On Fri, 10 Apr 2009 17:15:52 +0800 (SGT) > > Jeff Chua <jeff.chua.linux@xxxxxxxxx> wrote: > >> > >> Adding 200 records in iptables took 6.0sec in 2.6.30-rc1 compared to > >> 0.2sec in 2.6.29. I've bisected down this commit. > >> > >> There are a few patches on top of the original patch. When I reverted the > >> original commit + changing rcu_read() to rcu_read_bh(), it speeds up the > >> inserts back to .2sec again. > >> > >> I'm loading all the firewall rules during boot-up and this 6 secs slowness > >> is really not very nice to wait for. > > > > The performance benefit during operation is more important. The load > > time is fixable. The problem is probably generic to any set of rules, > > but could you post some info about your configuration (like the rule > > set), and the system configuration (# of cpu's, config etc). > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > > the body of a message to majordomo@xxxxxxxxxxxxxxx > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > Please read the FAQ at http://www.tux.org/lkml/ > -- 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
