Feeds

AMD alleges Intel compilers create crash code for its chips

Fork off

  • alert
  • submit to reddit

Designing a Defense for Mobile Applications

The lawsuit AMD filed against its arch-rival, Intel, alleges that a tweak in Intel's compilers can hinder the performance of code running on AMD processors.

According to the complaint: "Intel has designed its compiler purposely to degrade performance when a program is run on an AMD platform. To achieve this, Intel designed the compiler to compile code along several alternate code paths. Some paths are executed when the program runs on an Intel platform and others are executed when the program is operated on a computer with an AMD microprocessor.

"The choice of code path is determined when the program is started, using a feature known as 'CPUID' which identifies the computer's microprocessor. By design, the code paths were not created equally.

"If the program detects a 'Genuine Intel' microprocessor, it executes a fully optimized code path and operates with the maximum efficiency. However, if the program detects an 'Authentic AMD' microprocessor, it executes a different code path that will degrade the program's performance or cause it to crash."

Of course, how much damage this may have done in the real world is open to question. As one poster on Slashdot, which first noted, there's hardly evidence of code falling over left, right and center on AMD systems.

Equally, would developers creating binaries intended to run on AMD processors use Intel's compilers? You can expect Intel to optimise its compilers' output for the idiosyncrasies of its own CPU architectures, but not to make sure the code runs equally well on a competitors product.

Still, it's a big step from 'not optimising for rival processor architectures' to 'actively making code run more slowly on rival processor architectures', as AMD alleges.

Another Slashdot contributor claims this kind of thing goes back at least to January 2004 and Intel C++ 8.0. The poster claims Intel's assembly code for the memcpy command was clearly designed to be less efficient on non-Intel processors than the company's own chips. Intel developer support, he claims, said the code was optimised for the Pentium 4 and the other code was the simplest implementation for older CPUs, such as the PIII.

"It turns out that their special 'Pentium 4' memcpy, which I tested thoroughly in all kinds of situations, worked perfectly fine on an AMD Athlon and a Pentium III," he concludes and notes his decision to adopt a different compiler as a result.

Again, it's a fine line between generating good code for, say, P4s and lowest-common denominator code for everything else, and creating intentionally bad code for AMD CPUs. Many of the examples cited by Slashdot posters could easily arise from Intel's focus on P4 optimisation rather than making things difficult for AMD. Intel is, after all, under no obligation to ensure the code its compilers generate are optimised for AMD CPUs unless it explicitly says they are so optimised, which we don't believe is the case.

Either way, it's going to make for an interesting trial. ®

Related stories

EC officials raid Intel offices
Intel 'ditches' high-end 'Centrino 3' chipset
Intel and Dell thrilled to join the dual-core server chip era
Dixons disses AMD claims
AMD wants Intel evidence from 30 firms
AMD Japan sues Intel for $50m damages - and then some

The Power of One eBook: Top reasons to choose HP BladeSystem

More from The Register

next story
Apple fanbois SCREAM as update BRICKS their Macbook Airs
Ragegasm spills over as firmware upgrade kills machines
Attack of the clones: Oracle's latest Red Hat Linux lookalike arrives
Oracle's Linux boss says Larry's Linux isn't just for Oracle apps anymore
THUD! WD plonks down SIX TERABYTE 'consumer NAS' fatboy
Now that's a LOT of porn or pirated movies. Or, you know, other consumer stuff
EU's top data cops to meet Google, Microsoft et al over 'right to be forgotten'
Plan to hammer out 'coherent' guidelines. Good luck chaps!
US judge: YES, cops or feds so can slurp an ENTIRE Gmail account
Crooks don't have folders labelled 'drug records', opines NY beak
Manic malware Mayhem spreads through Linux, FreeBSD web servers
And how Google could cripple infection rate in a second
FLAPE – the next BIG THING in storage
Find cold data with flash, transmit it from tape
prev story

Whitepapers

Designing a Defense for Mobile Applications
Learn about the various considerations for defending mobile applications - from the application architecture itself to the myriad testing technologies.
How modern custom applications can spur business growth
Learn how to create, deploy and manage custom applications without consuming or expanding the need for scarce, expensive IT resources.
Reducing security risks from open source software
Follow a few strategies and your organization can gain the full benefits of open source and the cloud without compromising the security of your applications.
Boost IT visibility and business value
How building a great service catalog relieves pressure points and demonstrates the value of IT service management.
Consolidation: the foundation for IT and business transformation
In this whitepaper learn how effective consolidation of IT and business resources can enable multiple, meaningful business benefits.