LinuxPlanet: Emulex Connects To Linux

“Connecting an application server to a corporate network, via a
NIC, has its drawbacks. The main problem is that more than 50% of
the server’s CPU can be consumed processing small-block
input/output.

“An HBA (host bus adapter) can offload that I/O and return those
lost CPU cycles to the task of processing transactions, by the
server. It does this in three different ways:

• “The high performance microprocessors in the HBA manage the
  server’s I/O.
• “The HBA controls DMA (direct memory access) of the data to the
  host server. This offloads that task from the server CPU.
• “Finally, the HBA can batch process CPU interrupts, instead of
  doing them one at a time.

“Large scale, high speed transaction and storage processing I/O
is what HBAs are all about. Typical transfer rates are in the
neighborhood of 2 Gb/s…”

Complete
Story