In a message dated 11/11/04 5:38:34 PM Eastern Standard Time, [EMAIL PROTECTED] writes: On Thu, 11 Nov 2004 [EMAIL PROTECTED] wrote:
> Given these results, I would conclude that the raw routing stack in 5.3 > is 35-40% slower than its 4.x counterpart. > > The tests are easy enough to duplicate, so there is no reason to > question the numbers. Feel free to try it yourself. Obviously different > Mobos and CPUs will yield different numbers, but my experience with this > test is that the "differences" between the OS versions are linearly > similar on different systems. >(was just pointed at this thread, sorry if I missed other posts) > >FreeBSD 5.3 sees an observably higher per-packet processing costs than the >4.x branch due to in-progress changes to the synchronization and queueing >models. Specifically, the SMPng work has changed the interrupt and >synchronization models throughout the kernel in order to increase >concurrency and preemptibility (i.e., lower latency in interrupt-based >processing). However, this has increaseed the overall overhead of >synchronization on the stack. Thanks for the truth. I've been trying to get it for several weeks now. As for your tuning suggestions, I can't use anything kludgy or experimental. device polling, while it does increase efficiencies in some ways, adds other inefficiencies. Specifically most controllers don't interrupt on every packet under load anyway, and you have to increase the HZ, etc. But more importantly, the same gains (perhaps 3-5%) can be achieved with 4.x. My point is to see whether moving to 5.3 is worthwhile, and I think that device polling on both would be a wash. My personal opinion is that device polling is a negative, because the trade off of occasional livelock is substantial number of dropped packets, which is unacceptable. When you have the in-progress code solidified I'd be happy to test it. We don't use the native firewall so I really don't have time to test it for you. I've already spent 2 days to determine that we're not going to use 5.x... Tommy _______________________________________________ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
