The battle going on at the low end may have consequences at the high end.
There is a monumental change occurring in the IT market. It is perhaps the biggest change since IBM unintentionally invited Intel and Microsoft to become two of the biggest technology gatekeepers of our time. Of course, every year there is someone proposing a major change in the industry. Trust me, it is really happening this time. The change I am talking about is happening in your pocket, purse, or belt clip. Yes, I am talking about cell phones, which by the way is becoming a really bad description of what these devices do. I probably use my “smart phone” as a talking device about 25% of the time. Then there are those pad things.
Back the revolution. The connection to HPC will become clearer toward the end of this column, but first let’s talk about “the change.” If I were to ask you what is the most popular processor used in phones and pads, and you said, “ARM,” you would be correct. Now comes the trick question, “Who make ARM processors?” Not the ARM Holdings company. They design processors and license their designs to manufacturers. They also have a reputation for creating very low power designs. Interestingly, while almost everyone else was out ramping clocks and power consumption (until they hit a wall) ARM was chugging along addressing the low power end of the market. Now that low-power is all the rage, due to phones and pads, ARM has become quite a bit more popular.
Another thing that may surprise some people about ARM is that it is NOT x86 based. It was developed by Acorn computer in the early eighties and inspired by the MOS 6502 (used in the first Apple computers). They have since developed many processor designs and found success in licensing them to manufacturers. As the top-to-bottom owner of the technology, there is no dependence on x86 licenses or the need to manage “x86″ compatibility. In general, all modern x86 processors use a more efficient base instruction set than the original x86. Thus, additional circuits are needed to translate the instructions. More circuits means more transistors, which requires more power and creates more heat. ARM processors have no such requirement and as such they generally run much cooler than their x86 counter parts.
When we look at software, the story gets even more interesting. If you ask someone what are the leading phone operating systems and if they are well informed on the topic they would probably reply, “Apple, Android, and Symbian.” If they are not informed, they will of course say, “What is an operating system and why is it on my phone?”
Notice who is missing? Indeed, our favorite blue-screen OS from Microsoft. We all know that there are Windows phones and Microsoft is trying hard to grab a piece of the market, but gee Windows doesn’t really run on ARM — used to, doesn’t any more, probably working on that though. There is more. While I am in my question asking mode, ask yourself this, “Given that you now have a choice, do you want your Windows desktop experience on your phone?” My guess is some will, most won’t.
My armchair analysis leads me to the following conclusion. The growth of personal computing (i.e. phones and pads) will favor ARM and Android (Linux). Of course, Apple IOS will thrive and do well, but virtually all the other handset and pad manufacturers will use Android. Symbian was just shot in the head by the Nokia-Microsoft deal, so I figure it has little chance here, even though it is open. Some of the low power X86 offerings will have some play as well. The AMD Fusion processors will be particularly interesting and, this is the important part, they are not really a true x86 processor because they have both x86 cores and stream processors on the die (the 9 Watt AMD Ontario C-50 runs at 1GHz has two Bobcat cores and 80 stream processors!). With AMD fusion an embedded array processor (i.e. GPU) is standard issue.
The Intel Atom according to Charlie Demerjian over at SemiAccurate may not fair so well. (Note: I usually don’t plug other web sites, but I find SemiAccurate to be a “tell it like it is” site that cuts through the industry “fluff and shine” used to promote most technologies. Plus, Greg Pfister who wrote the seminal “In Search of Clusters,” has recently joined the SemiAcurate team.)
There is also one other advantage that ARM has over the x86 market. The shear number of vendors who have licensed and integrated ARM into their products. I have previously mentioned NVidia Tegra 2. Other notable ARM based processors include, Marvell XScale, Nintendo, ST-Ericsson Nomadik, Qualcomm Snapdragon, the Texas Instruments OMAP product line, the Samsung Hummingbird and the Apple A4. Writing code for ARM sure covers a lot of phones.
If you have been wondering what all this has to do with HPC, think about how the whole cluster revolution (disruption) got started. There were pioneering people using commodity hardware to do HPC. In 1994, the first “Beowulf” used 486DX4 chips and 10BT Ethernet. Laughable at the time — and very effective for some problems. ARM Holdings has recently announced the Cortex A15 a low power 8-core server processor that can be used for HPC. That is right I said HPC.
Remember, lower power means less cooling, higher density, and lots of cores. In my next installment, I will speak to the software elephant that is standing next those shinny new cores, ARM, x86, stream, or otherwise.
Douglas Eadline is the Senior HPC Editor for Linux Magazine.