Date: Thu, 13 Oct 2005 13:22:43 -0400 From: John Baldwin <jhb@freebsd.org> To: sean@mcneil.com Cc: scottl@freebsd.org, freebsd-amd64@freebsd.org, Mike Tancsa <mike@sentex.net> Subject: Re: realtek performance (was Re: good ATI chipset results) Message-ID: <200510131322.45968.jhb@freebsd.org> In-Reply-To: <1129223254.9093.3.camel@server.mcneil.com> References: <6.2.3.4.0.20051013090818.07a5c9a0@64.7.153.2> <200510131149.24411.jhb@freebsd.org> <1129223254.9093.3.camel@server.mcneil.com>
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On Thursday 13 October 2005 01:07 pm, Sean McNeil wrote: > On Thu, 2005-10-13 at 11:49 -0400, John Baldwin wrote: > > On Thursday 13 October 2005 11:13 am, Sean McNeil wrote: > > > On Thu, 2005-10-13 at 09:17 -0400, Mike Tancsa wrote: > > > > Havent really seen anyone else use this board, but I have had good > > > > luck with it so far > > > > > > > > http://www.ecs.com.tw/ECSWeb/Products/ProductsDetail.aspx?DetailID=50 > > > >6&Me nuID=90&LanID=0 > > > > > > > > Its a micro ATX formfactor with built in video and the onboard NIC is > > > > a realtek. (Although its not the fastest NIC, its driver is stable > > > > and mature-- especially compared to the headaches people seem to have > > > > with the NVIDIA NICs.) > > > > > > Is this the RealTek 8169S Single-chip Gigabit Ethernet? > > > > > > For those interested, here are some changes I always use to increase > > > the performance of the above NIC. With these mods, I can stream over > > > 20 MBps video multicast and do other stuff over the network without > > > issues. Without the changes, xmit is horrible with severe UDP packet > > > loss. > > > > So, I see two changes. One is to up the number of descriptors from 32 rx > > and 64 tx to 64 rx and 64 tx on some models and 1024 rx and 1024 tx on > > other modules. The other thing is that you seem to pessimize TX > > performance by always forcing the send packets to be coalesced into one > > mbuf (which requires doing an alloc and then copying all of the data) > > instead of making use of scatter/gatter for sending packets. Do you need > > both changes or do just the higher descriptor counts make the difference? > > Actually, I've found that the higher descriptor counts do not make a > noticeable difference. The only thing that mattered was to eliminate > the scatter/gather of sending packets. I can't remember why I left the > descriptor increase in there. I think it was to get the best use out of > the hardware. Hmm, odd. Scott, do you have any ideas why m_defrag() plus one descriptor would be faster than s/g dma for re(4)? -- John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve" = http://www.FreeBSD.org
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