The goal of this section is to laugh through the multiple attempts at defining new DSPs , next craze DSPs, further than DSPs, beyond DSPs , everything and their contrary as we went from 1995 to 2005 . Among the most notables we will have a quick pass at: Media processors.
Now, the obvious question is: why should we care? Once more, the answer is that there is a very large difference in use model between a GP full market CPU and a COP.
What is ridiculous in one case becomes brilliant and maybe most effective for the given application (see NVIDIA evolution). Also some of the brightest architects of our time were involved in the design of these new machines. Finally this is still one of the riches vein of ideas available publicly (but not freely) (IEEE, ACM, MDR, etc..).
BACKGROUND
There are two reasons why we feel sad about this "Idiot Wind" period .- Too many people were getting carried away and too many arguments just did not make sense.
- For instance we computed it would take 1200 men years of application software (not tools) just to meet the minimum requirements of fulfilling the claim of being a Media processor.
- For a while, we went in the same direction, (and we have to thank the influence of Jim Turley for that) (mind you he changed his mind pretty quickly too).
DESCRIPTION AND TYPES
- Type 1
- Video Signal Processors
- Video DSP
- Media Processors
- Type 2 Legoland
- Multi IP DSP, Cluster Based DSP
- Bops, Cell, Improv, Equator
- atsana, chipswright, clearspeeed, craddle, e-lite, powerFFT, sandbridge, siroyan, synputer, telairity, tops, trips
- Infinite-tech RADarray (neil stollon ICSPAT 99)
- RADarray of RADcore coprocessors connected to host
- Host and peripherals are 3rd-party IP
- Each RADcore is a reconfigurable stream algorithm coprocessor.
- Each RADcore is made of user selected Execution Units (EXUs) interconnected by reconfigurable data path bus architecture
- EXUs form independent elemental processing blocks such as ALUs, MACs, memories, I/O,etc..
- Type 3 Domain DSP
- Wireless DSP,
- Speech, Audio DSP
- Broadband DSP
- Custom DSP, configurable DSP,
- Reconfigurable DSP
Media Processor (MP) (or MVP) (V for Video)
Born around 92-94, the MVP had a peak around 1997, went through multiple "down and up"s before final death by 2005.The most famous (first wave) names were TriMedia, MicroUnity, Chromatics, NVidia [ref.1]They had several characteristic in common:
- It was a new type of processor (the MEDIA processor)
- from our DSP perspective it was a bit baffling. Why not use a DSP?
- They were the latest incarnation of the MultiMedia (MM) craze.
- very soon followed by MM extensions. Compare MP and MM extension
- For some reasons most were based on VLIW.
- Why?
- While 5 of 7 MM functions could be done by a DSP, they rightly believed that a DSP would not be able to do the last 2 (video and graphics).
- But then why do they think they could?
- What were the 7 functions?
- Finally, the most obvious characteristic was their disdain for the Pentium. In a typical Silicon Valley Fashion, after loosing the Risc war, that was the new frontier.In a nutshell:
- First they lost the PC seat to the Pentium (that was CISC versus RISC)
- Then they (re lost) the PC MM seat to the Pentium (that was GP processor versus Media processor)
- Finally they could not even find a small coprocessor seat in the PC, i.e. to be used as a Media COP!!
- This is the point which merits attention. See NVIDIA below
- In their final days, to add insult to injury they were totally inadequate for the embedded market.
- Mind you, good luck trying DVD in 1999 or cell phone in 2000 with a 288 bit wide opcode and no software support!
In the most remarkable feat of the century, NVIDIA changed direction by focusing on graphics instead of a rainbow of applications [ref.2].
Not sure about their recent direction towards general purpose, people never learn it seems!
TriMedia
In another example of adaptation, the champion of VLIW, after years of trying software optimization instead redesigned their chips with two multiple powerful video coprocessors. Also important, Phillips concentrated on platforms and Trimedia became "the other core" of the Nexperia platform. Instead of ARM+DSP it was MIPS+TriMedia. Mind you, the latest instantiation of the platform could be ARM + COPs.
Definitely a good DSP core, the TriMedia was a relatively simple 5 issue machine, had some neat tricks (fusing of operations at the register file ports) and very eearly code compression. [ref 6,7,8,9]
MicroUnity MediaProcessor
Original coiner of the term, famous for John Moussouris, MicroUnity was the first on the scene and the first to die; they set the architecture standard for a single core parallelism pretty high. [ref 10,11]. They had a following with Equator.
Chromatics MPACT
The other Media Processor, noticed for its 792-bit datapath (if today it sounds peanuts, at the time the standard was 64-bit)... currently dead. [ref 12]
Offer from the East
As can one expect, Japan and its all powerful integrated consumer industry were not the last to follow the hype with their own offering
- Sharp DDMP (1997)
- NEC MP98 (MPR March2000)
- Toshiba MEP (after giving up MPACT) (EPF 2002)
- Fujitsu (was their VLIW a Media Processor?)
- Hitachi ??
- Matsushita ??
Among the Noise
While not serious commercial products, the MVPs developed by Universities and Research labs had interesting features. These are 2 examples we were familiar at the time but there are litteraly 100s of them [ref 13,14].
- University of Hannover HiPAR {search Johannes Kneip} (IEEE Video for Circuit and systems 1996)
- Impressive X,Y memory
- Infineon VIP {search Uli Ramacher} (Hot Chips 13)
The TI C80 also known as MVP (1993) remains an excellent architecture example. It is NOT a Media processor. Its was designed like any other DSP, with an ambitious target in MIPS which happened to be video conferencing. Now as part of the strategy obviously the target was anything in the same order of MIPS magnitude. Most interesting it was a host+4xDSP core solution. Even more: how can you be so wrong in the memory model? (refer to somewhere else in this Blog).
Lessons Learnt
NVIDIAHeadline1: MultiMedia processor becomes UniMedia processor.
Headline2: Media processor becomes Graphics solution..
And they had enormous success as Pentium "Coprocessor" .
Now this is an important lesson, for co-processing. As a general purpose co-processing MM chip, the MVP architecture was a complete failure. As a "very focused" co-processing solution point, it is part of the standard PC architecture.
Microunity, Chromatics, TriMedia
It would be silly to forget these architectures. On one hand, more recent and better architectures have been developed but on the other hand they are not so visible.
Further: the GPU story
Obviously these are still questions (we have to wait another 3-5 years to learn the lesson):
- KEY: is there a place for another type of computing (the GPU)?
One has to bear in mind that in 40 years of silicon computing (except for a short time of DSP) all attempts to compete with the general purpose model ended up in abject failures.
- what kind of the processing model is the dual head(CPU+GPU) adopted by AMD ?
- in the same way, what kind CPU+GPU is the Apple model?
References
- John.A.Watlington "Video signal processors" , circa 1997, http://wad.www.media.mit.edu/peole/wad/vsp/node1.htm from a web site which (as usual) has gone pining for the woods. Too bad , it contained an excellent and succint table of comparison.
- Section news" NVIDIA changes direction" EBN December 23,1996 issue:1038
- Bernard Cole "New processors up multimedia's punch" EET February 3, 1997.
8. Lee, W., Kim, Y., Gove, R.J., and Reed, C.J., “MediaStation 5000: Integrating Video an - it is more the answer from CPUs (MM extensions) to MM processors.
- Jim Turley "Multimedia chips complicate choices" MDR Feb 12, 1996 page 14
- Maury Wright "Media Procesors target digital video Roles" EDN sep 1, 1998
- Tom Halfill "Philips Trimedia goes Mobile " MPR dec 5, 2005
- Gert Slavenburg and his biking pal "DSPCPU operations for TM1100" 1999, Appendix A, Preliminary information
- Gert Slavenburg, etc..'Custom operations for Multimedia" Chapter 4 of the same reference
- Peter Clarke " Compressed VLIW meets multimedia" EE Dec, 1995
- Craig Hansen "MicroUnity MediaProcessor Architecture" IEEE micro, 1996
- quote "A broadband mediaprocessor extends and streamlines a general-purpose computer system to attain the goal of communicating and processing digital video, audio, data and RF signals (SIC!) at broadband rates using compiled, downloadable, software rather than special-purpose hardware. The instruction set, system facilities, and initial implementations of an architectural family of broadband mediaprocessors are introduced, and compiled software development is illustrated with an example and description of the development environment".
- John Moussouris (easy to remember mouse+souris) "A roadmap of the Mediaprocessor Design space" Microdesign Resources Dinner May 9, 1996
- Yong Yao " Chromatics's Mpact2 boosts 3D, MPR Nov 18, 1996
- SSC 27 12, dec 92 p1886
- SSC 29 12, dec 94 p1474
- http://www.cse.fau.edu/~borko/Chapter21_mc.pdf
- Just added this morning, just wished I had read it before.kind of complement to our MM splash. Hey Borko is it public?
Answer to questions
The 7 functions:- graphics including 3D
- video (compression, editing , conferencing)
- high quality Audio
- computer telephony, Speech
- communications, Fax, Modems
- real time 3D games
- DVD?
No comments:
Post a Comment