The Bulldozer Opteron is a complete makeover of the chip in an attempt to gain back what has become an eroding AMD share of the chip market.
They're real workhorses, capable of running lots of virtual machines, said Margaret Lewis, director of server software for AMD, in an interview. That makes Bulldozer a candidate for cloud service providers as well as enterprise data centers that wish to maximize workloads per virtualized host, she said. For example, a single rack full of 16-core 6200s can host 672 virtual machines, with each VM having its own core, Lewis said.
At the same time, the Bulldozer architecture represents a rearrangement of chip components on the surface of the chip die. Lewis called Bulldozer's combination of two eight-core dies a chip
module. What's new is that each module represents two integer units and a single floating point unit. Under an Intel definition of cores, each core would have its own integer and a floating point unit. AMD has reshuffled the deck and announced that two cores have two integer units and a single, shared floating point unit. This makes sense since in virtualized server operations, where the floating point unit is typically used less than half the time, compared to integer operations.
Under certain circumstances, critics say this approach will hurt single-threaded performance involving floating point operations, such as in a scientific application on an individual desktop. That doesn't appear to be AMD's concern as it aims for the virtualized enterprise server and cloud data center markets.
The integer units can work faster because they share things that make sense to share, said Lewis. That includes the Level 1 and Level 2 caches as well as the floating point unit.
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