Intel Investors - Merced Software Compilers , Code Generators and OS Support details are beginning to emerge.
Here is a review of the breadth of software development already underway for Merced!
This may turn out to be an immense Cottage Industry in its own write!
Paul
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techweb.cmp.com
Merced software is taking
shape
By Alexander Wolfe
SANTA CLARA, Calif. - Intel Corp. is
seeding the development of a new
generation of 64-bit compilers and operating
systems. Surprisingly, Java won't play a key
role when the Merced MPU hits the streets in
1999. Rather, the stalwart C++ programming
language will lead the Merced software
parade, with compilers currently in the works
at Intel, Hewlett-Packard and Microsoft. Two
lesser- known software companies
Metaware Inc. (Santa Cruz, Calif.) and
Edinburgh Portable Compilers Ltd.
(Edinburgh, Scotland) are also developing
heavy-duty, Merced-capable compilers.
On the operating-system front, a number of
Unix-related efforts now under way at
Hewlett-Packard, Sun Microsystems, Digital
Equipment and Sequent could spark a
resurgence for that OS. But Unix will be met
head-on by Microsoft, which is forging
ahead with a 64-bit version of Windows NT.
"Microsoft
is
really
under
the
gun
to
produce
a
good,
64-bit
Windows NT because there will definitely be
multiple versions of Unix for Merced," said
Michael Slater, principal analyst at
MicroDesign Resources (Sebastopol,
Calif.). "It's a big opportunity for Microsoft.
On the other hand, Unix can get entrenched
if NT is not seen as a strong option."
As for compilers, Slater sees Merced as
ushering in a new era of software
one-upmanship. "The quality of the compiler
will have a much bigger effect on
performance than do compilers for today's
architectures," he said. "With multiple efforts
in the works, there's probably never been
this competitive a compiler environment."
Both the compiler and the OS projects have
received scant attention amid the intense
emphasis on details of the chip's highly
parallel hardware architecture, but industry
experts believe that the software will be the
key factor in how rapidly Merced moves into
real-world usage.
At the same time, these experts see tough
challenges ahead for software developers.
Writing compilers for Merced is no easy
trick, because the microprocessor uses two
techniques-called speculation and
predication-which haven't yet been applied
extensively in real-world production
applications.
"If you look at what the RISC people went
through, it took them about six to eight years
after the introduction of the various
architectures to really get good, optimizing
compilers that worked well almost all the
time," said a noted compiler developer who
requested anonymity. "I see the same thing
happening with Merced. It will take a couple
of years for things to really solidify."
For its part, Intel sees rapid progress.
"There's a very clear synergy between the
compiler and the hardware," said Satya
Prasad, a senior marketing engineer at Intel.
"This enables us to achieve a very high
degree of instruction-level parallelism."
To attain such parallelism, Merced contains
many execution units which the compiler
must constantly feed with instructions that
have been organized into simultaneously
executable blocks. Moreover, to take
advantage of the key predication and
speculation techniques relied upon by
Merced, the compiler must be adept enough
to enable the MPU to skip over unnecessary
branches and to avoid memory latency,
respectively.
Indeed, Rich Fuhler, Merced lead developer
at compiler vendor Metaware Inc., sees
predication as "the most interesting
challenge" to come out of Merced. He
pointed out that feature is also used in the
ARM architecture, which has full predication,
and in HP's PA-RISC, which uses partial
predication.
Predication removes branches from an
application program by essentially executing
both pre- and post-branch instructions
simultaneously. The results from instructions
that wouldn't have been executing during a
real-world run through the code are then
thrown away.
The rub, Fuhler explained, is that predication
can't be done blindly. "Do you want to fill up
your cache with dead code?" he asked. "If
you're going down a very hot path in the
code, the answer is no.
So the question becomes, when do you
predicate? We're doing a lot of work on that
right now."
The second technique, speculation, masks
memory latency by taking load instructions
out of their normal place in the middle of a
branch, and moving them up to be executed
as early as possible in the program.
Here, too, Fuhler sees work for compiler
designers. "The challenge is to get good
speculation that doesn't affect performance
in another basic [code] block," he explained.
"The biggest question is, what happens to
cache locality? If you're going to be bringing
in a new cache line, then the load is not
movable."
To effectively use Merced with real-world
apps, Fuhler believes that software
developers will have to get their hands dirty.
"I don't think a compiler can be right 100
percent of the time," he said. "This kind of
stuff will have to be [aided] by performance
feedback analysis. As a developer, you're
going to have to take a more active role."
Such analysis tools are already making their
way into common usage. For example, Intel
offers VTune, which presents programmers
with graphical views of "hot spots" in their
code that can benefit from optimization.
Among compiler vendors, the big battle
could revolve around the back-end code
generator-the software "black box" which
handles the tough task of converting the
intermediate output of a compiler into a final
stream of machine code. Metaware is rolling
its own code generator; reportedly, HP and
Microsoft are also doing in-house
implementations.
Adopting a broader strategy, Intel is writing
its own code generator and is licensing it to
other vendors. "Merced has a lot of
challenging features and Intel wants to
ensure they're properly exploited to achieve
the performance that's expected," said Geoff
Millard, chief executive officer of Edinburgh
Portable Compilers. "We've been working
closely with Intel to integrate our compilers
with their code-generator technology."
Operating angle
Proving that the compiler efforts are not
occurring in isolation from the OS work,
Edinburgh has forged a potent link with
Sequent. According to Millard, his
company's new Merced C compiler is being
used by Sequent in their effort to port Digital
Unix to IA-64. Sequent is billing the
implementation as the only "little-endian" OS
that will offer compatibility across both
Merced and Alpha CPUs.
Along with Sequent, the flurry of
Merced-oriented Unix activity included the
announcement last week from HP that it is
putting together a Merced-capable version
of its HP-UX operating system and has
licensed the technology to Hitachi, NEC and
Stratus Computer.
Not to be left on the sidelines, Sun
Microsystems Inc. is also making a strong
play for its Solaris OS. Fujitsu, which is a
major Sun reseller in Japan, is helping port
Solaris to Merced.
While some observers see a Unix
juggernaut forming, Microsoft remains
unconvinced. "Merced hasn't even shipped
and the Unix market is already fragmenting,"
charged Ed Muth, Microsoft's group product
manager for Windows NT.
Muth said that Microsoft's 64-bit port of NT
to Merced will be ready when Merced ships
in volume. At the WinHEC conference in
March, Microsoft offered an early peek with
a preliminary release of its 64-bit software
developer's kit.
Microsoft has already prepared the code
base it will use to implement NT on Merced.
"The work we're doing on 64 bits is based
on NT 5.0 source code," said Muth. "We
have invested a great deal of effort to make
NT 5.0 64-bit-ready."
Once the OS ships, Microsoft is poised for
an increasingly aggressive thrust into the
engineering space. "We expect to make
major investments to more broadly position
NT as part of the technical workstation and
technical server markets," Muth said,
specifically pointing to applications such as
EDA.
From the compiler side of the equation,
however, some vendors are sticking with
Unix. "Microsoft is trying to defeat Unix with
NT and they're a formidable competitor,"
said Frank DeRemer, chief executive officer
of Metaware. "On the other hand, they tend
to usurp all of the business opportunities on
their side of the field. So for us, the more
profitable niche is Unix." |
