Date: Sat, 8 Sep 2007 12:00:31 +0200 From: Claudio Jeker <cjeker@diehard.n-r-g.com> To: freebsd-net@freebsd.org Subject: Re: OS choice for an edge router Message-ID: <20070908100031.GA4563@diehard.n-r-g.com> In-Reply-To: <20070907235622.C410D5B58@mail.bitblocks.com> References: <46E1D74D.3070409@freebsd.org> <20070907235622.C410D5B58@mail.bitblocks.com>
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On Fri, Sep 07, 2007 at 04:56:22PM -0700, Bakul Shah wrote: > > This is not the case. Flood ping doesn't reach the limit in any > > way. Have a look at the ping man page and flood ping description. > > Ah yes, I was forgetting about the strict synchrony. > > > Stock FreeBSD 6.2 or 7.0 can easily do 500kpps with good network > > cards and fastforwarding enabled. On a dual-Opteron 2.6GHz with > > PCI-X Intel and Broadcom network cards I've done 800kpps in-out. > > What is the throughput when fastforwarding is not used and > packets go to different destinations? Note that typically > fastforwarding does not help much on a router since only one > route is cached. Wrong. Fastforwarding does not cache routes, it is more a process-to- completion frowarding bypassing a lot of unneeded code. > > > > Listen to what Louis Mamakos said! Use FreeBSD primarily for > > > the control plane. May be there are NICs where you can > > > offload some packet forwarding.... But that is a substantial > > > change to FreeBSD. Or live with what FreeBSD can do on a > > > given box. > > > > There are no NICs known that can do packet forwarding offload. > > And neither is there support in FreeBSD for that. You're probably > > confusing this with checksum offloading or TSO (TCP segmentation > > offloading) which isn't an issue with packet forwarding at all. > > Indeed. That is why I said "that is a substantial change to > FreeBSD"! But even offloading checksum can help as the CPU > has less to do. > Wrong. A router only needs to check and update the IPv4 checksum and doing that can be done in a few simple instructions. There is no need to look at the TCP or UDP checksum. So in the end checksum offloading has little effect on forwarding performance. -- :wq Claudio
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