Feeds

Intel disables hot new TSX tech in early Broadwells and Haswells

Attention devs: this one weird tick might just bork your boxen

Choosing a cloud hosting partner with confidence

One of Intel's new ways to make software go faster is called Transactional Synchronization Extensions (TSX), an innovation that gives developers fine control over how multi-threaded code uses a CPU's resources.

TSX is a reasonably big deal, because as Intel never tires of pointing out it long-ago decided that grunt alone is not the way to keep Moore's Law alive. Chipzilla instead decided that cleverness is the way to go, hence today's multi-core chips and innovations like TSX that allow developers to use just about every cycle they offer.

So far so good … except for one small problem first noticed by Techreport, namely that TSX is broken in early batches of CPUs that are supposed to offer the feature.

The problem is described in this errata document (PDF) for the Xeon E3-1200 v3 Product Family. Errata are Intel's notes about chip performance.

The one for TSX offers the following advice:

Problem: Under a complex set of internal timing conditions and system events, software using the Intel TSX instructions may result in unpredictable system behavior. Implication: This erratum may result in unpredictable system behavior. Workaround: It is possible for the BIOS to contain a workaround for this erratum.

That workaround is a motherboard firmware update that, once installed, pushes a microcode patch to the processor to simply turn TSX off. Once it's off, so is the chance of “unpredictable system behavior”.

Intel's saying the workaround, and the bug, are not a big deal and won't be present in Haswell products once they ship in volume. That will happen with the forthcoming Haswell-EX, an 18-to-20-core bruiser expected to land in early 2015.

Chipzilla's also advising that you can, if you choose to do so, tweak firmware so that TSX will work in current CPUs. With “a complex set of internal timing conditions and system events” required to trigger the bug, that may well mean that developers can at least play with TSX in non-production environments. Which may well be the dominant use for the technology at this point in its life anyway. ®

Beginner's guide to SSL certificates

More from The Register

next story
Ex-US Navy fighter pilot MIT prof: Drones beat humans - I should know
'Missy' Cummings on UAVs, smartcars and dying from boredom
Don't wait for that big iPad, order a NEXUS 9 instead, industry little bird says
Google said to debut next big slab, Android L ahead of Apple event
Xperia Z3: Crikey, Sony – ANOTHER flagship phondleslab?
The Fourth Amendment... and it IS better
Netscape Navigator - the browser that started it all - turns 20
It was 20 years ago today, Marc Andreeesen taught the band to play
A drone of one's own: Reg buyers' guide for UAV fanciers
Hardware: Check. Software: Huh? Licence: Licence...?
The Apple launch AS IT HAPPENED: Totally SERIOUS coverage, not for haters
Fandroids, Windows Phone fringe-oids – you wouldn't understand
Apple SILENCES Bose, YANKS headphones from stores
The, er, Beats go on after noise-cancelling spat
Here's your chance to buy an ancient, working APPLE ONE
Warning: Likely to cost a lot even for a Mac
prev story

Whitepapers

Forging a new future with identity relationship management
Learn about ForgeRock's next generation IRM platform and how it is designed to empower CEOS's and enterprises to engage with consumers.
Cloud and hybrid-cloud data protection for VMware
Learn how quick and easy it is to configure backups and perform restores for VMware environments.
Three 1TB solid state scorchers up for grabs
Big SSDs can be expensive but think big and think free because you could be the lucky winner of one of three 1TB Samsung SSD 840 EVO drives that we’re giving away worth over £300 apiece.
Reg Reader Research: SaaS based Email and Office Productivity Tools
Read this Reg reader report which provides advice and guidance for SMBs towards the use of SaaS based email and Office productivity tools.
Security for virtualized datacentres
Legacy security solutions are inefficient due to the architectural differences between physical and virtual environments.