Intel disables TSX after bug is discovered in Haswell and some Broadwell CPUs

[Scorpus]

One of the new features included with Intel's Haswell CPUs was Transactional Synchronization Extensions, or TSX. This set of instructions can improve the performance of multi-threaded applications when a developer uses its corresponding library, and was touted as one of the main improvements in their latest CPUs.

Due to their relatively recent introduction, only a few software developers were testing out TSX-enabled applications. One such developer discovered a critical bug (or "errata" as Intel calls it) in the CPU's implementation of TSX that could cause software failures, which Intel subsequently acknowledged.

In response to the discovery of the bug, Intel has decided to disable TSX on all Haswell processors through a microcode update, which are delivered through motherboard firmware updates. The update should improve the stability of Haswell systems, at the expense of TSX functionality.

It's unusual for Intel to simply disable a feature rather than implement a workaround, suggesting the TSX issues are hardware-related and can't be addressed on any software level.

As the errata was discovered recently, it also affects Intel's upcoming server-oriented Haswell-EP products, as well as Haswell-E for enthusiast consumers, and the first line of Broadwell chips, Broadwell-Y (Core M). All will ship with TSX disabled, although developers testing TSX code on Haswell-EP machines will be able to enable TSX through an option in the firmware.

Intel is giving developers and option to enable TSX on their Xeon products so TSX-enabled software can be ready by the time higher-end Haswell-EX CPUs are released. Haswell-EX parts, along with all future Intel processors and the rest of their Broadwell line, will have the errata corrected by the time they're ready for production.

As TSX is geared towards server applications rather than consumer applications, there's not much to worry about for now. However this will undoubtedly slow the development of TSX-enabled software, which isn't ideal for Intel or those looking for more performance out of their CPUs.

Permalink to story.

https://www.techspot.com/news/57726-intel-disables-tsx-after-bug-is-discovered-in-haswell-and-some-broadwell-cpus.html

 

[ypsylon]

Somebody please explain to Intel what errata (since ancient times) means. Seems like some breakdown in communication and understanding of a simple word...

Or perhaps is that some kind of newspeak?

 

[captaincranky]

Somebody please explain to Intel what errata (since ancient times) means. Seems like some breakdown in communication and understanding of a simple word...

Or perhaps is that some kind of newspeak?

http://en.wikipedia.org/wiki/Erratum

 

[dividebyzero]

Somebody please explain to Intel what errata (since ancient times) means. Seems like some breakdown in communication and understanding of a simple word...

It's my understanding that erratum refers to a correction issued after printing. The fact that Intel are issuing a correction to expected program execution due to incorrect printing (lithography) of the IC's logic blocks seems within the purview of the word.
The term errata has been interchangeable between the actual list and the events contained within the list since they started publishing erroneous IC behaviour in February 1996 following the Pentium FDIV bug.

 

[yukka]

So this affects Haswell macs I assume as well?

 

[dividebyzero]

So this affects Haswell macs I assume as well?

Same silicon.
As for the degree the bug affects Haswell, the TSX ISA extension isn't used in any commercial software at this time.

 

[Darth Shiv]

There certainly won't be mature software based on the tech! Often when doing microcode updates for issues like this, they don't disable the feature entirely but put in a clunky workaround so it must have been a fair showstopper.

 

[Guest]

Ok.. basically some government detected that TSX was espionage for the NSA and forced intel to disable it, of course that the government that did this is corrupt... and received billions to shut up, very soon some government is going to show great economic success...

 

[Guest]

After reading this news some days ago I decided to check if TSX was still enabled on my DZ87KLT-75K + Core i7-4770K to my surprise the TSX was disabled by Intel on the DZ87KLT-75K by the BIOS 0452 which had a Processor Update/Microcode Update on the release note those were the only new things in that BIOS which we thought were for haswell refresh but we were told in the Intel community that it was not for haswell support rather a microcode update now I know what it was intended for.

 

[cowcreekgeek]

ERRATA, in regard to Intel, was what I thought to be an acronym created by upper-level management, for ERRoneous Atempts To Air-cool 5.0+GHz.

But, back to this one -- TSX is far more than merely some unimportant feature to some folks, and for far more than server-related applications. In fact? It's the most compelling reason I had for my latest build: This feature held the greatest potential for increasing productivity that I've seen in years, and seeing it disabled by default is a tragedy.