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Network card

Network card

Posted Nov 4, 2010 0:17 UTC (Thu) by cma (guest, #49905)
In reply to: Network card by cma
Parent article: KS2010: Linux at NASDAQ

OK...found the tacnology term: DCA (Direct Cache Access)

One example: http://www.dell.com/downloads/global/products/pwcnt/en/nic-intel-gb-et-brief.pdf


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Network card

Posted Nov 4, 2010 15:39 UTC (Thu) by i3839 (guest, #31386) [Link]

See http://daniel.haxx.se/blog/2008/12/18/10g-and-direct-cach...
It's also known as I/OAT.

To quote bgoglin:

> DCA doesn’t really reduce the memory bandwidth requirements since the
> data still has to be fetched by the cache from the main memory (the
> device doesn’t write into the cache, it just tells the cache that data
> should be fetched). The whole point of the approach is that this fetch
> is done in advance, so you don’t have to wait for it when the host starts
> processing the packet.

So it doesn't seem that good yet.

With integrated memory controllers I would think it's easy to do this automatically, or at least very easily, by directly going to the cache first instead of through RAM (at least the L3 cache).


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