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Sun Microsystems is trying to rally an industry consortium
around its approach to supporting transactional memory, a key piece of
the puzzle of tomorrow's parallel programming systems. The move comes
at a time when Sun hopes to be the first to implement the technology in
a server microprocessor.
Sun will describe its Rock processor in a paper at the International Solid-State Circuits Conference in San Francisco Monday (Feb. 4). Abstracts released by ISSCC show the 2.3 GHz Rock aims to be the first CPU to implement transactional memory, also known as atomic transactions.
Sun Microsystems is trying to rally an industry consortium
around its approach to supporting transactional memory, a key piece of
the puzzle of tomorrow's parallel programming systems. The move comes
at a time when Sun hopes to be the first to implement the technology in
a server microprocessor.
Sun will describe its Rock processor in a paper at the International Solid-State Circuits Conference in San Francisco Monday (Feb. 4). Abstracts released by ISSCC show the 2.3 GHz Rock aims to be the first CPU to implement transactional memory, also known as atomic transactions.
By tagging groups of instructions to execute
at essentially the same time, the technique reduces the complexity and
inefficiency of current locking mechanisms used to synchronize
operations, especially in large database software. Computer
scientists have long seen the feature as one of the initial planks of a
new parallel programming model that will be needed for multi-core
architectures.
Today's use of locks represent "an inherently pessimistic approach. The
whole effort of locking files is wasted 99 percent of the time," said
Nathan Brookwood, principal of market watcher Insight64 (Saratoga,
Calif.).
As the first to implement atomic transactions, Sun risks being
ahead of broad industry support. So far, it's unclear whether industry
giants including IBM, Intel, Microsoft, Oracle and others will back Sun
approach in processors and database software.
Representatives from Microsoft—which has done significant research on
the topic--declined to respond for this article. It is still possible
competitors could be motivated to define a competing standard before
Rock-based systems ship.
As far as third-party databases
and other applications, "I believe we will have ISVs support for this
the day we ship [Rock-based] systems," said Marc Tremblay, chief
technology officer of Sun's microelectronics group.
Sun is working to create a consortium that would define an
applications programming interface for its implementation of atomic
transactions and make the API available as open source software. At least two large computer user organizations are backing the move, Tremblay said.
The synching mechanism in widely-used Java code maps well to the new
Rock instructions. In addition, Sun's Solaris operating system and
thread libraries will support atomic transactions so users can get
immediate benefits, he added.
The company is also developing a simulator for its approach that will
be released as open source software. Sun will deliver a paper at the Transact
conference in February describing the simulator and its early findings
on Rock's support for atomic transactions. The company hopes to release
the simulator at the conference.
"We have found some encouraging results and some pitfalls," working
with the simulator, said Mark Moir, a senior staff engineer developing
the simulator at Sun.
Moir said the implementation atomic transactions in Rock is
limited and is not intended to support all conditions or instructions.
Therefore Rock may abort an atomic transaction at any time, turning the
key synchronization effort back over to software.
"We are not trying to solve all the problems with transactional
memory--that's too hard," said Moir. "It will be easy to poke holes in
this implementation by finding things it is not useful for, but this
gives us a place to start from which we can improve," he added.
Indeed, one of the goals of the simulator is to get the
technology quickly into the hands of researchers who can find ways to
improve it. "We also have had some contact from developers who want to
explore how they can quickly support this new technology," said Moir.
The simulator is based on the Gems
simulator from the University of Wisconsin which is itself based on a
simulator from Virginia Tech. Sun hopes to release the simulator to the
Gems team in Wisconsin so they can release and maintain it as part of
their ongoing efforts.
The Sun version only approximates the atomic features of Rock and is
not meant to be an accurate model of its performance, Moir said.
Sun is a few weeks from getting a "version 2.0" of Rock back
from the fab. It expects to ship the part in systems within a year,
said Tremblay.
Read the original article: http://www.eetimes.com/showArticle.jhtml?articleID=206100676
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