NEW YORK – A bug found in Intel's Haswell processors may have the potential to disrupt some large database operations, but most users will likely not encounter any issues. The transactional synchronization extensions (TSX) built into Haswell add hardware transactional memory support, but aren't generally invoked by typical PC applications, analysts said.
Transactional memory is a data-locking technique that can help certain types of multithreaded applications, typically database programs, run faster. Intel published a report documenting the errata, which include incorrect address reports when an exception/interrupt occurs in 64-bit mode, uncorrectable errors resulting in system hang and internal timer errors, and unexpected updates to the last exception record. Intel disabled the bug through a microcode patch.
"TSX is still relatively obscure in terms of usage, so I don't look at it as being very serious," said David Kanter, a microprocessor analyst with The Linley Group and Real World Technologies.
Intel and an unnamed researcher found the bug as the Haswell debuted in June 2013. Reports said the error will be included in upcoming Broadwell Y-series chips for use in Core M-based tablets. Those Broadwell chips will also have TSX disabled via microcode.
"Hopefully it'll get fixed in Broadwell. What's more important is that it gets fixed in server versions,” that run the kind of big database programs that sometimes use transactional memory, Kanter said, adding the errata may not be fully fixed until Intel debuts its 22 nm Skylake architecture.
Intel declined comment on TSX beyond reaffirming the company's commitment “to correcting the issues with TSX and enabling the feature on future processors.”
Analyst Patrick Moorhead with Moor Insights and Strategy said he doesn't believe the TSX bug will affect Intel's business or developers' desire to work with the instruction set.
"I don't think it is a big deal en masse; I'm sure it's inconvenient for people who were hoping to have that functionality,” Moorhead told EE Times. "TSX is really the cherry on top, the other 99.9% of Haswell's installed base isn't going to be inconvenienced at all."
Processors geared for large servers have been adding support for transactional memory in recent years, a trend Intel was attempting to join with Haswell and TSX. Moorhead and Kanter said, at most, the errata is "a little embarrassing" for Intel.
— Jessica Lipsky, Associate Editor, EE Times