Austin, Texas -- IBM and Freescale, which had a parting of the ways after co-developing the Power microprocessor in the 1990s, have reunited their efforts through the Power.org group.
One of the biggest hurdles the companies face is whether they can resolve their longtime differences as to which on-chip bus they will ride into the multicore future. Freescale is holding close to one of the more promising candidates, its own CoreNet technology.
Though IBM has asked for technical details of the on-chip fabric, Freescale has not been forthcoming. A Freescale source who asked not to be identified said there is a debate within the company about whether it should keep the CoreNet technology proprietary, license it to IBM or open it up to all comers through Power.org.
Freescale considers its interconnect a key ingredient in a family of multicore processors it eventually will roll out across all of its chips, starting with 45-nm products next year. The bus can stretch to data rates beyond 1.8 GHz, linking as many as 32 cores.
"At the end of the day, we think our multicore architecture could help us get performance boosts of 2 to 3x," said Jeff Timbs, director of marketing for Freescale's networking group, who has been evangelizing the architecture.
A Power.org technical committee is about to issue a report concluding there is no immediate hope of creating a standard on-chip bus for the fledgling Power community, because all the players involved seem to be going their own way.
In addition to Freescale, with its CoreNet, Applied Micro Circuits Corp. (AMCC) has licensed the ARM AXI bus, and startup PA Semi has its own Connexium interconnect.
IBM is said to have delayed development on the next-generation of its Core Connect, the PLB6, hoping the issue would be resolved. The current PLB4 version is apparently adequate for any 2008-class designs the company has in the works. But IBM will likely reactivate the PLB6 design next year if no other alternative emerges.
All the players recognize the future is moving to system-on-chip designs that use multiple cores, accelerators and other blocks. They want to share resources as much as possible, since their architecture lacks the economies of scale of the competing X86 and ARM worlds. And they know it would be easier to attract third-party chip designers if they had a common, open interconnect.
Beyond that, little is known about the exact nature of the debates inside Freescale and IBM or the talks between them. But it's clear the matter needs to get resolved soon.
"You would think Freescale would be more open--after all, standards are what Power.org is supposed to be about," said Tom Starnes, a longtime embedded processor analyst and former Motorola employee. "This sounds like the old Motorola semiconductor group [that has become Freescale] is afraid of enabling a competitor," said Starnes, principal of Strategy Sanity (Austin).
"There are so many things that go into a complete chip that the details of the on-chip interconnect might not make that much difference," he added.
IBM and Freescale had a painful parting of the ways several years back, and reuniting is not easy. Their PowerPC aspired to rival the X86 in mainstream computers when it was conceived in 1991, but after a few years it became clear Apple would be their only child. When Apple CEO Steve Jobs publicly announced in 2005 that the company was switching to the X86, it was a body blow for the Power duo.
From 1998-2006, IBM and Freescale went their separate ways. IBM focused on its Power servers, sold its embedded Power business to AMCC and continued to provide Power cores to all comers. Freescale continued to develop embedded versions of Power for its own use.
But maintaining leading-edge fabs and design capabilities to keep pace with Intel Corp. is an ex- pensive business for Big Blue. IBM has always needed help funding that effort. So it got quite a boost when Microsoft, Nintendo and Sony all agreed to use Power-based chips for their current generation videogame consoles.
In March 2004, longtime IBM veteran Nicholas M. Donofrio made a speech to IBMers calling for them to take a cue from the rising world of Linux and open up the Power archi- tecture. A group of managers responded, creating Power.org in 2004. Freescale joined in 2006, and the group held its first technical conference--the Power Architecture Developer Conference--here this week as a sort of recommit- ment ceremony.