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"Custom 18 core arm chips (too much for A7-9, too little for M0-4, really weird number of cores)" Could just look at the website instead of speculating http://

• rasz_pl 11y ago
  ARM9E, wow that is ancient, 15 year old nintendo DS ancient. Not even R4 (if they really really need realtime oriented core).
  • m_mueller 11y ago
    AFAIK the Xeon Phi is based on something in between Pentium I and II cores. So the idea is about the same. I'd put my money on ARM when it comes to efficient chip architecture, since efficiency was their goal from the start (x86 was always about backwards compatibility first).
    • DiabloD3 11y ago
      No, the Phi is a P6 core, but so is all the modern Core family CPUs. All Phis are along the lines of modern cores stripped down and simplified. This is also how the modern Avoton and newer Atoms work, but the Phi is stripped down even farther.
      • m_mueller 11y ago
        That's not what I get from Intel's documentation. Intel seems to call it a Pentium I with a P6 programming interface. But maybe you have other sources, if so please share. > So why not use an older, smaller but still very capable core? And that is what they did. The designers went back generations, literally back to one of the first modern cores, the Intel® Pentium® processor. [1] > The foundation for the Intel® Xeon Phi™ coprocessor core PMU is the PMU from the original Intel® Pentium® processor (aka P54C). Most of the forty - two performance events that were available in the original Intel® Pentium® processor are also available on the Intel® Xeon Phi™ coprocessor The core PMU has been upgraded to an Intel® Pentium® Pro processor - like (“P6 - style”) programming interface. [1] https://software.intel.com/en-us/blogs/2013/03/22/the-intel-xeon-phi-coprocessor-what-is-it-and-why-should-i-care-pt-1-fitting-it-all https://software.intel.com/en-us/blogs/2013/03/22/the-intel-... [2] https://software.intel.com/sites/default/files/forum/278102/intelr-xeon-phitm-pmu-rev1.01.pdf https://software.intel.com/sites/default/files/forum/278102/... (section 1.2)
        • DiabloD3 11y ago
          All a PMU is, is a performance monitoring unit. It keeps track of CPU utilization and performance counters. This is an extremely small part of the CPU, and yes, I can imagine they jettisoned a lot of stuff you find on modern cores because it takes up too much room.
          • m_mueller 11y ago
            Good point, that source wasn't really what I thought it is. There's still enough sources to support my argument though. > The cores at the heart of Intel’s first Xeon Phi are based on the P54C revision of the original Pentium and appear largely unchanged from the design Intel planned to use for Larrabee. [3] > Many changes were made to the original 32-bit P54c architecture to make it into an Intel Xeon Phi 64-bit processor. [4] - so, still, they seemed to have started with Pentium I and adding stuff to it rather than stripping out a modern core. Which was always the story they sold about Larrabee, which AFAIK was the direct predecessor project that got salvaged with Intel MIC. [3] http://www.extremetech.com/extreme/133541-intels-64-core-champion-in-depth-on-xeon-phi http://www.extremetech.com/extreme/133541-intels-64-core-cha... [4] https://software.intel.com/en-us/articles/intel-xeon-phi-core-micro-architecture https://software.intel.com/en-us/articles/intel-xeon-phi-cor...
            • DiabloD3 11y ago
              It is closer like this: ARM, and all the companies that have their own ARM designs, have a library of parts. They assemble those parts as needed to complete designs for themselves and for customers. What people don't understand is, Intel does the same. Look at how modern E3s, E5s, E7s, i3/5/7s, modern Atoms, etc, all work: similar designed parts, all paired with what is minimally required for that design to work and perform the way they want. Intel doesn't throw designs out, they keep them and periodically make sure they still work on smaller fab sizes and newer fab techs. A more striking example than the Phi is the Intel Quark, featured in the Edison platform, which is Intel's equivalent of an ARM Cortex-M series (such as the M4s used in a lot of cell phones as a GPS/motion sub-processor and other things). The Quark really is a modernized P54C (Pentium 1 pre-MMX) core, and more so than the Xeon Phi is (although, obviously, there is shared part design through both of them). I think the thing with Phi is, its rapidly evolving. Larrabee was closer to this design than first gen Phi was, and now they're shipping second gen Phi, and it looks more like how some GPUs have been historically designed than just x86 core spam (look at how the bus design is evolving, they're getting closer and closer to how AMD and Nvidia design theirs, and also how post-Skylake on-die GPU integration is evolving on multi-socket platforms). So, yeah. I don't agree that the Phi can be flat out called a P54C, but I agree they have been reusing modernized parts from that era because it is easier to do that than continually strip down existing designs to look like that. The Quark, however, looks a lot like how embedded family 286 and 486s have been kept alive for the embedded hardware sector, and now they're positioning the Quark for the IoT era (which, hey, they have my interest with that product, so they did something right); the Quark is more of a P54C than the Phi is.
  • aidenn0 11y ago
    Taped out in in 2010 before the r4 was announced.