Date: Wed, 22 Mar 2006 10:52:41 -0800 (PST) From: Arne Woerner <arne_woerner@yahoo.com> To: "Jin Guojun \[VFFS\]" <g_jin@lbl.gov> Cc: freebsd-performance@freebsd.org, oxy@field.hu Subject: Re: packet drop with intel gigabit / marwell gigabit Message-ID: <20060322185241.98216.qmail@web30312.mail.mud.yahoo.com> In-Reply-To: <44219619.7020900@lbl.gov>
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--- "Jin Guojun [VFFS]" <g_jin@lbl.gov> wrote: > Even after your program finished, you had only 277 MB/s (DDR memory?), > which is far below a good motherboard. Good motherboards should > have 500 - 900 MB/s memory bandwidth, while expensive motherboards > can have 1-3 GB/s memory bandwidth, which are suitable for 10 Gb/s NIC. > Hmm... Ok... Yes, DDR and 266FSB... So you meant, I would have about 500MByte/sec... Then I am far below that... My formula was: 8*277MByte/sec = 2.16...Gbit/sec -- Since dd reads and writes memory I multiplied that with 2, which results in 4.328...Gbit/sec (50%read, 50%write) throughput... Or does a write(2)-request to /dev/null just return without reading the buffer? If yes, it would be just 2.16Gbit/sec for filling the buffer with zeroes... Then we should look again at the bandwidths in oxy's(?) setting... I thought he just needed 500Mbit/sec alltogether (disc io, NIC io)... > It sounds like you have a A7V8X or similar motherboard, Do you? > It is an ECS K7VMM or K7VMM+ if I recall it correctly... Bought in 2003... Is it easy to explain, why the 266FSB cannot do 8Gbit/sec without problem? I mean: 2*133MHz*32bit=8.3125Gbit/sec... Is the MMU too slow (e. g. due to "cheap" implementation of cache strategies) to utilize the FSB to the maximum? -Arne __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com
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