August 25, 2011
Intel Raises the Curtain on Poulson
At the Hot Chips conference last week, Intel disclosed additional details about the upcoming Poulson Itanium CPU due for shipment early next year. For Itanium loyalists (essentially committed HP-UX customers) the disclosures are a ray of sunshine among the gloomy news that has been the lot of Itanium devotees recently.
Poulson will bring several significant improvements to Itanium in both performance and reliability. On the performance side, we have significant improvements on several fronts:
- Process – Poulson will be manufactured with the same 32 nm semiconductor process that will (at least for a while) be driving the high-end Xeon processors. This is goodness all around – performance will improve and Intel now can load its latest production lines more efficiently.
- More cores and parallelism – Poulson will be an 8-core processor with a whopping 54 MB of on-chip cache, and Intel has doubled the width of the multi-issue instruction pipeline, from 6 to 12 instructions. Combined with improved hyperthreading, the combination of 2X cores and 2X the total number of potential instructions executed per clock cycle by each core hints at impressive performance gains.
- Architecture and instruction tweaks – Intel has added additional instructions based on analysis of workloads. This kind of tuning of processor architectures seldom results in major gains in performance, but every small increment helps.
- Instruction replay – Beyond performance, Intel has added the ability to re-execute a failed instruction. This is a powerful capability for enhancing reliability, and a first for Intel. Instruction replay allows a failed instruction to be retried without the overhead of refetching all of the data, and is triggered by a number of low-level failures. The attraction of this technology is that it happens at a very low level of the hardware, and is completely hidden from the OS and application software. This feature will add to the already impressive reliability of HP-UX running on Itanium-based systems, complimenting the server level end-to-end retry capability in HP’s Superdome (primarily enabled in HP's SX3000 chipset on the Superdome II).
Does Anyone Care?
With the bloody divorce of HP and Oracle, with Intel as an embarrassed spectator, does anyone still care about Itanium? Simple answer – the thousands of Itanium customers who are either not running Oracle or understand that they have time, in some cases three to five years, before they have to migrate away from their current systems. While the Oracle breakup will definitely hurt HP’s Itanium business, it will not kill it outright, and HP-UX running on Itanium systems will still remain a highly reliable platform for many users. These users will be rewarded with an Itanium platform that will have improved reliability as well as an impressive boost in performance from today’s offerings. While HP has not made any public statements about systems or availability, there is nothing immediately evident about the current Superdome II architecture that makes it inappropriate for Poulson.
Beyond Poulson the future gets a bit fuzzy. Intel has one visible generation of Itanium beyond Poulson named Kittson. Kittson should appear in 22 nm process in approximately 2014. Beyond that our crystal ball gets a bit fuzzy. Intel is releasing no details, adn HP has clearly stated that they are committed to Itanium for the remainder of its life. Nontheless Kittson and one successive performance bump might be the end of the line for Itanium, which would mean that its evolution may stop on or about 2016, plenty of time for HP and its users to come to terms with HP-UX on an x86 platform based on x86 CPUs that will have gone through approximately three additional product cycles by then.