Haswell Architecture Improvements

We have discussed the advantages that the Haswell core brings here in more detail. In a nutshell:

  • The core can sustain about 10% more integer instructions per clock cycle than its predecessor, Ivy Bridge. 
  • Virtualized applications should perform slightly better thanks to the lower VM exit/entry latency.
  • HPC applications could/should benefit much more if they are recompiled to make use of the improved AVX2 and Fused Multiply Add (FMA) support
  • Database transactional applications should benefit more thanks to the lower synchronization latency.
  • In-memory databases should benefit if they are adapted to make use of the AVX-2 256 bit integer vector operations.  

Again, the same is true about the Xeon E5-2600v3. So what makes the E7 special? 

Transactional Synchronization Extensions: I'll be back 

There is one "new" - or rather "now working" - feature: TSX or the famous Transactional Synchronization eXtensions. These extensions are all about making locking more "optimistic" (you let the CPU handle the bookkeeping to maintain consistency). TSX is quite powerful, but also can be a liability in the wrong use case. Developers will need a deep understanding of the locking and parallel programming to be able to make good use of TSX, as 

  1. ... you still have to rewrite your code (inserting hints)
  2. TSX may reduce performance in some situations: if indeed a pessimistic lock was necessary, the transaction has to be re-executed with a "traditional" conservative way of locking. You could call it a "lock misprediction".  

Introducing TSX in software requires assessing the different locks in application, using different libraries and quite a bit of of tuning. SAP and Intel did this for the expensive in-memory data mining SAP HANA software.  

 

The upgrade from "Ivy Bridge EX" to "Haswell-EX" yielded 50% performance, while introducing TSX roughly doubled performance. So in TSX enabled data mining software, Haswell-EX has the potential to reduce the waiting time by a factor of 3 and more. 

Xeon E7 v3 System and Memory Architecture Xeon E7 v3 SKUs and prices
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  • PowerTrumps - Saturday, May 9, 2015 - link

    Oracle has been unable to develop a power core let alone a processor. What they have done is created servers with many cores and many threads albeit weak cores/threads. The S3 core was an improvement and no reason to think the S4 won't be decent either. However, the M7 will come (again, true to form) with 32 cores per socket. It will be like 8 mini clusters of 4 cores because they are unable to develop a single SMP chip with shared resources across all of the cores. As such, these mini clusters will have their own resources which will lead to latency and inefficiencies. Oracle is a software business and their goal is to run software on either the most cores possible or the most inefficient. They have both of these bases covered with their Intel and SPARC business.

    Also, performance per Watt is important for Intel because what you see is what you get. With Power though, when you have strong single thread performance, strong multi-thread performance and tremendous consolidation efficiency due to Power Hypervisor efficiency means ~200W doesn't matter when you can consolidate 2, 4 maybe 10 Intel chips at 135W each into a single Power chip because of this hypervisor efficiency.
  • tynopik - Friday, May 8, 2015 - link

    pg4 - datam ining
  • der - Friday, May 8, 2015 - link

    Woo...we're bout to have another GHz War here!
  • usernametaken76 - Friday, May 8, 2015 - link

    I'm sure you mean figuratively. We've been stuck between 4-5 GHz on POWER architecture for closing in on a decade.
  • zamroni - Friday, May 8, 2015 - link

    My conclusion is Samsung should buy AMD to reduce Intel dominance.
  • alpha754293 - Friday, May 8, 2015 - link

    It would have been interesting to see the LS-DYNA benchmark results again (so that you can compare it against some of the tests that you've ran previously). But very interesting...
  • JohanAnandtech - Friday, May 8, 2015 - link

    Give me some help and we'll do that again on an update version :-)
  • alpha754293 - Tuesday, May 12, 2015 - link

    Not a problem. You have my email address right? And if not, I'll just send you another email and we can get that going again. :) Thanks.
  • andychow - Friday, May 8, 2015 - link

    If Samsung bought AMD, they would lose the licence for both x86 and x86_64 production. It would in fact ensure Intel's dominance of the market.
  • Kevin G - Friday, May 8, 2015 - link

    The x86 license can be transferred as long as Intel signs off on the deal (and it is in their best interest to do so). What will probably happen is that if any company buys AMD, the new owner will enter a cross licensing agreement with Intel.

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