On Sun, Nov 27, 2005 at 10:59:14PM +0300, Gleb Smirnoff wrote: > Ruslan, > > On Sun, Nov 27, 2005 at 09:45:45PM +0200, Ruslan Ermilov wrote: > R> Nope, I need this caching. It's for looking up the same table > R> several times in a row but with various values. For example, > R> we use ipfw tables to route the traffic to the correct dummynet > R> pipe, where value is the bandwidth, and this caching helps a lot. > > Have you benchmarked that this caching is important? On a router > that serves a lot of parallel traffic flows the caching is not > a benefit, but additional processing. I think we should optimize > the code for more loaded environments, since we don't care about > CPU consumption in a less loaded setup - whether it is 0.1% or 0.11%. > I'm talking about the following case: the same packet is processed by a firewall ruleset that has N rules that look up the same ipfw table but with different "values", to select a correct dummynet pipe.
> In general such kind of caching in network code is an old fashion, > that causes a problems when we attempt to make code more > parallelizable. We alreade removed rtcache in ip_output.c rev. 1.201 > and we will soon remove route caching in gif(4), because it causes > problems on SMP. > > Can you try my patch? Since it reduces the total number of mutex > operations it should be a win on UP, too. > We're currently based on 4.x. You can try it yourself: create a table with 10000 entries and with value 13. Then write a ruleset with 13 rules that look up this table so that the last rule looks it up with value 13, and do a benchmark. Let me know what are results with and without caching. Cheers, -- Ruslan Ermilov [EMAIL PROTECTED] FreeBSD committer _______________________________________________ freebsd-net@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to "[EMAIL PROTECTED]"
