On 29/01/18 09:17 PM, Alvin Starr via talk wrote:
A number of groups have tried to develop extremely parallel processors but all seem to have gained little traction.
There was the XPU 128, the Epiphany(http://www.adapteva.com/) and more recently the Xenon Phi and AMD Epyc.
At one point I remember reading a article about sun developing an asynchronous CPU which would be interesting.
Many experiments of that era fell flat, as did the attempt at at an async Sun.
All these processors run into the same set of problems. 1) x86 silicon is amazingly cheap. 2) supporting multiple CPUs cause more software support for each new CPU architecture. 3) very little software is capable of truly taking advantage of many parallel threads without really funky compilers and software design tools. 4) having designed a fancy CPU most companies try very hard to keep their proprietary knowledge all within their own control where the x86 instruction set must be just about open source now days. 5) getting motherboard manufacturers to take a chance on a new CPU is not an easy thing.
My benchmark for processor success is: Does several of Asus,Supermicro,Tyan,Gigabyte et al make a motherboard for this CPU.
Even people with deep pockets like DEC with their Alpha CPU and IBM with their Power CPUs have not been able to make a significant inroad into the commodity server world. Mips has had some luck with low to mid range systems for routers and storage systems but their server business is long gone with the death of SGI. Sun/Oracle has had some luck with the Sparc but not all that much outside their own use and I am just speculating but I would bet that Sun/Oracle sells more x86 systems than Sparc systems.
All those companies, plus H-P, hit critical mass: people ported their software to them. Without that, you're stuck with x86 supersets. And if you don't keep succeeding, customers defect to the competition. Oracle fell off the table a few years back, recognized it and laid off their Solaris team. Their present is x86 and Fujitsu SPARC, and their future is purpose-built x86 with hyperchannel.
ARM seems to be having some luck but I believe that luck is because of their popularity in the small computer systems world sliding into supporting larger systems and not by being designed for servers from the get go.
I am a bit of a processor geek and have put lots of effort in the past into elegant processors that just seem to go nowhere. I would love to see some technologies other than the current von Neumann somewhat parallel SMP but I have a sad feeling that that will be a long time coming.
With the latest screw-up from Intel and the huge exploit surface that is the Intel ME someone may be able to get some traction by coming up with a processor that is designed and verified for security.
Compilers folks have given up on software-only magic: the T1/T5 showed that hardware could contribute greatly, and I suspect hardware-software co-design may be the next thing we see. A more secure non-speculative processor might suffice, but I don't know if it will be based on SPARC, POWER or something resembling an x86 microcode will be most attractive to the market. I do know it will run Linux. --dave
On 01/29/2018 05:36 PM, David Collier-Brown via talk wrote:
Kunle Olukotun didn't like systems that wasted their time stalled on loads and branches. He and his team at Afara Websystems therefor designed a non-speculating processor that did work without waits. It became the Sun T1.
-- David Collier-Brown, | Always do right. This will gratify System Programmer and Author | some people and astonish the rest davecb@spamcop.net | -- Mark Twain