In article <[EMAIL PROTECTED]>,
Deepak Jain <[EMAIL PROTECTED]> wrote:
>
> The new P4s are shipping with 800mhz RAMBUS memory modules. Wouldn't 2GB of
> 800mhz RAM go a long way to evening out the performance between a PC/FreeBSD
> box and all but the most specialized, packet-pushing ASICs?
I doubt it. My understanding is that RAMBUS memory is faster for
long burst transfers, but that its random access latency is actually
worse than that of conventional memory. Your routing table lookups
(random accesses into a huge data structure) would be slower, not
faster. There is very little bulk copying in the IP forwarding path
of the kernel, so the higher bandwidth of RAMBUS would not provide
much benefit. I suppose it would speed up the DMA transfers between
the NICs and RAM. But I still bet overall performance wouldn't be
improved by the use of RAMBUS memory.
John
--
John Polstra [EMAIL PROTECTED]
John D. Polstra & Co., Inc. Seattle, Washington USA
"Disappointment is a good sign of basic intelligence." -- Ch�gyam Trungpa
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