MIPS Strikes Back: 64-bit Warrior I6400 Arrives
by Stephen Barrett on September 2, 2014 10:00 AM EST
Introduction
One of ARM’s most tangible business advantages is its offer of both CPUs and GPUs to SoC designers. Anyone with experience in business to business relationships knows just how complex forming and maintaining a mutually beneficial collaboration can be. Setting up contracts, forming rapport, defining goals, and even just understanding documentation and technical content formatting all takes time. Unless there is significant benefit to investing in two different relationships and technologies, it is simpler (read: cheaper) to single source contributing components of a design. There are down sides of single sourcing (see Boeing 787 battery fiasco), but depending on a business’ capacity for risk, the savings are undeniable. Especially when ARM undoubtedly offers bundle pricing promotions.
When Imagination Technologies acquired MIPS Technologies in 2012 for $100 million, their goal was very clear – attack ARM. Imagination’s GPU business was already wildly successful, with design wins in a bevy of high end mobile devices including those from Samsung and Apple. Adding the CPU cores from MIPS, with their decades of history designing and licensing IP, strategically positioned Imagination opposite ARM’s licensing business. Imagination’s executives have also stated they are prepared to offer aggressive IP bundling discounts.
Looking at Imagination’s product, press, demos, and interviews, it appears they are not (yet?) positioning MIPS cores to combat ARM cores at the high end of the market. Rather, they appear focused on being a viable alternative to ARM in multi-threaded and low power workloads. In fact, the vast majority of MIPS cores are currently used in network infrastructure where threading and power efficiency are paramount.
Today MIPS is announcing a major launch: the Warrior I6400 core. Based on the 64-bit MIPS64 instruction set (release 6), the Warrior I6400 core is the middle-class CPU core in a family of three, each targeting a different point in the power/performance curve. Imagination is releasing the I6400 core last, which is at the middle of the pack balancing performance with power. Imagination has already released their high-end P56xx series and low-end M51xx series.
The most analogous ARM core to the I6400 appears to be the ARM Cortex-A53, but I6400 has some interesting features we haven’t seen in this market before and MIPS estimates it will deliver higher performance. I’ve produced a table here to help put performance in context. Note that only A57, A53, P5600, and I6400 are 64-bit processors.
| MIPS and ARM High End IP Cores in Order of Performance | ||
| MIPS |
Manufacturer Estimated DMIPS/MHz/core |
ARM |
| 5.0 | Cortex-A57 | |
| 4.0 |
Cortex-A17 Cortex-A15 |
|
| P5600 | 3.5 | |
| I6400 | 3.0 | |
| 2.5 | Cortex-A9 | |
| 2.3 | Cortex-A53 | |
| 1.9 | Cortex-A7 | |
Keep in mind that these processors use different instruction sets (ISAs) so DMIPS are not directly comparable. However, as they are both RISC processors, the DMIPS should hopefully be roughly comparable. I would like to use directly comparable CoreMark scores but only MIPS provides CoreMark numbers for their processors.
While no one can accurately predict if Imagination will grab additional market share away from ARM, we can educate ourselves on this alternative before it potentially arrives in our hands and homes. And besides, competition is always a good thing.
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extide - Tuesday, September 2, 2014 - link
No.. it's correct, and it has nothing to do with Android L. NDK apps are compiled directly to a specific ISA. For java apps, Android L/ART works the same way as Dalvik ... the only difference is WHEN the compiling to native code happens.coder111 - Tuesday, September 2, 2014 - link
Imagination technologies? Same company that's responsible for the disaster that was the GPU in Intel Poulsbo? With no drivers coming to Linux and the most hostile approach to any Linux driver development?And they want to succeed in embedded/mobile space, where lots of things run Linux? I hope they change their stance on open-source development and hardware support, and soon...
dwforbes - Tuesday, September 2, 2014 - link
Imagination Technologies, the makers of PowerVR used in a significant percentage (if not majority) of mobile devices, doesn't just want to succeed -- they have been fairly dominant for years.Lonyo - Tuesday, September 2, 2014 - link
I think that's an Intel problem partially, and it would be interesting to see if Imagination changes their approach. Intel licensed the GPU but didn't have all the access they need to develop proper drivers, and Imagination didn't care as it was a third party chip using their IP, I'd guess.It's 50/50 Intel not being sensible with the licensing and Imagination not feeling a need to care.
And yes, they were a mess. DXVA support didn't exist in XP and caused BSOD every time, and in Win Vista/7 it didn't really do much, from my own personal non-Linux experience. No support for that GPU, but I'd mainly blame Intel for not managing to sort it out when they licensed the IP. They are the ones putting their name on the product and seem to have forgotten to sort out a proper way to support it, and Imagination probably don't care when they have their money.
When it's Imagination's name on the side they would probably care.
extide - Tuesday, September 2, 2014 - link
You mean Imagination Technologies who has been the GPU provider in all of the Apple SOC's in All of the iPhones, iPads, and MANY existing android devices already on the market? That whole Atom GPU disaster was really more of Intel's fault than IMG's.patrickjchase - Tuesday, September 2, 2014 - link
On page 3 you state "even though the core is listed by Imagination as in-order, the SMT feature (when present) allows the I6400 to behave as a superscalar core".Superscalar and out-of-order are orthogonal concepts. It is possible to have a core which is superscalar but not OoO (Cortex-A7/A8/A53, MIPS R5000, the original Pentium) as well as a core which is OoO but not superscalar (IBM 360/91, the very first OoO design). Note that all of the examples I gave do not use SMT/Hyperthreading.
Stephen Barrett - Tuesday, September 2, 2014 - link
I cleaned up that paragraph. Thank you for the feedback. I think I got my wires crossed when Imagination's details discussed superscalar at the same time they discussed SMTSarahKerrigan - Tuesday, September 2, 2014 - link
"I would imagine the superscalar execution is limited to the next two instructions within a thread (as there is no reorder buffer); otherwise the entire core wouldn’t be listed as in-order."The diagram clearly shows that it can issue two ops from two different threads in a cycle. This is what makes it *simultaneous* multithreading, instead of fine-grained multithreading.
There have been plenty of examples of in-order cores with SMT - for instance, the first-gen Atom core could issue from both hardware contexts in the same cycle, as could the lightweight dual-issue in-order PowerPC core in the Xbox 360 and the Cell. Issuing from multiple contexts per cycle isn't dependent on reorder capability.
Stephen Barrett - Tuesday, September 2, 2014 - link
Yes that was hopefully made clear in the previous paragraph about how SMT works. What I was discussing in that quoted sentance is the superscalar execution capability of a single thread (not SMT). See the preceeding sentance in the same paragraph "Even though the core is in-order, the I6400 performs superscalar execution for a given thread. Since it is dual dispatch, two instructions from a single thread can be executed in parallel."alexvoica - Tuesday, September 2, 2014 - link
It behaves like a superscalar CPU when used in a single threaded configuration and like an in-order design in multithreading variants.