More details on Calxeda’s latest ARM server processor - a tweaked version of the Cortex-A9 that is specifically designed for enterprise computing.
Calxeda, formerly known as Smooth-Stone in reference to the river rock that the mythical David used in his sling to slay Goliath, doesn’t think the server racket can wait for the 64-bit ARMv8 architecture (announced late last week) to be designed and tested in the next few years.
And that is why Calxeda has spent the past several years tweaking the 32-bit ARMv7 core to come up with its own system-on-chip (SoC) and related interconnect fabric suitable for hyperscale parallel and distributed computing where nodes have only modest memory needs.
Today, Calxeda takes the wraps off its much-anticipated ARM server processor, which has been given the name EnergyCore in reference to the fact that like other ARM chips used in smartphones and tablets, it is focused on doing computing work for the least amount of energy possible. The idea is that by switching to ARM cores, Calxeda can do a unit of computing work burning less juice than an x86 chip from Intel or Advanced Micro Devices, the Power chip from IBM, the Sparc T from Oracle, or the Itanium from Intel.
The EnergyCore ECX-1000 Series chips, as the first EnergyCores will be called, are based on the Cortex-A9 designs from ARM Holdings. The ECX-1000 chips are in fact based on a quad-core implementation of the Cortex-A9 chip, but like other server implementations of the ARM chips, such as the X-Gene announced last week by Applied Micro Circuits, there is a lot more to these chips than the core.
There is a slew of other stuff, including a fabric interconnect and a management controller that would otherwise be an add-on for the system board, on the chip. One big difference between the EnergyCore and X-Gene is that the latter is based on the 64-bit ARMv8 and won’t ship until the second half of next year if all goes well at Applied Micro. And that will be early silicon. It remains to be seen when server makers will pick up the X-Gene chip and actually get it into servers, but that might take until 2013.
Calxeda thinks there’s money to be made now, and for some workloads, the EnergyCore chips are going to fit the power bill. “ARM does for the processor world what Linux did for the operating system world,” Karl Freund, vice president of marketing at Calxeda, tells El Reg. “It opens up the chip market to a whole lot of innovation.”
The ECX-1000 chips are implemented in a 40 nanometer process and are manufactured by Taiwan Semiconductor Manufacturing Corp, which seems to be the foundry of choice for server chip makers that don’t have their own wafer baking facilities. Each Cortex-A9 core runs at 1.1GHz or 1.4GHz and includes a scalar floating point unit that can do single-precision or double-precision operations as well as a NEON SIMD media processing unit that has 64-bit and 128-bit registers and that can also do floating point ops…
Calxeda is not trying to do cache coherency over one to four ECX-1000 sockets on a system board or across the 1,024 possible system boards that the integrated fabric switch scales to. And it is not particularly worried about latencies as parallel workloads pass data around this switch fabric.
"If you look at the workloads we are aiming at, they are not latency sensitive," says Freund. This includes offline analytics like MapReduce big data chewing, Web applications, middleware and Memcached, and storage and file serving. It would be interesting to see how a network of these puppies runs a shared-nothing database cluster.
The topology of the EnergyCore Fabric Switch can be changed on the fly from one style to another and the settings are stored on flash memory on the chip package. Bandwidth can be dynamically allocated in 1Gb/sec, 2.5Gb/sec, 5Gb/sec and 10Gb/sec virtual pipe sizes by the fabric switch and presents two Ethernet ports to the operating system.
The idea is to eliminate the top-of-rack Layer 2 switch that is typically used in a cluster these days with the on-chip switch. While it is possible to build a cluster with 4,096 ECX-1000 chips by using 10Gb/sec XAUI cables and the four ports coming off the Calxeda board to cross link them all, Freund says that most companies will put two real 10GE switches in a rack and use these like end-of-row switches and only lash together 72 four-socket nodes (about a half rack of servers) with the integrated fabric.
The other important thing about that EnergyCore Fabric Switch is that is has dynamic routing, which means you can get around congestion in a network of nodes and also, in conjunction with that management controller, optimize operations for latency or reduced power consumption – or boosted power consumption if you have some work that needs to run faster…
It’s hard to imagine server makers won’t be lining up to get their hands on these EnergyCards. And if they want to start selling them right away, Calxeda is good with that, too. The chips will be able to run Canonical’s Ubuntu and Red Hat’s Fedora Linuxes to start; Windows Server 8 could eventually get there if Microsoft gets interested. (So far, it has made no commitments, even with Windows 8 for clients and mobile phones getting an ARM port.)
The ECX-1000 chips will sample in late 2011, right on time, and volume shipments of the chips will start in the middle of 2012. That is about when Applied Micro will begin sampling its 64-bit X-Gene chip, which has its own crossbar switch but one that implements up to 128-way symmetric multiprocessing across 64 of its two-core chips.
It will be interesting to see how these two ARM server chips compete against each other as well as against other RISC chips and Intel Xeon and AMD Opteron processors. And remember, graphics chip maker Nvidia, which sells ARM-based SoCs for smartphones and tablets, has also promised ARM chips of its own designs for PCs and servers. Thank heavens for a little competition to keep Intel and AMD honest. Or whatever you might call it.