Recent Developments: OpenPOWER's Potential HPC Comeback

Those who suggested that IBM's scale out servers were just a half-hearted effort that would quickly get strangled by the desire to protect the high margin big iron servers could not have been more wrong. IBM just launched 3 new servers, and all of them are affordable scale out servers. IBM is now very aggressively going after the market it has (almost) completely lost to Intel's Xeon: HPC. At the same time IBM is emphasizing the determination to play an important role in the emerging "machine learning" and "Big Data" market.

The S822LC "Big Data" and S821LC use mature and proven – some would say "older" – technology: the "OpenPOWER version" of the POWER8 and NVIDIA's Tesla K80. There are some interesting new facts to discuss though. First of all, these servers are made by Supermicro, confirming the close relation between the two companies and that OpenPOWER is indeed "Open". Supermicro is the market leader in the HPC market, and the fact that Supermicro chose to invest in OpenPOWER is a promissing sign: IBM is on to something, it is not another "me too" effort.

Secondly, these servers use (registered) DDR4 RAM as opposed to DDR3 as found in servers like the S812LC and SL822. Since they are still communicating via the "Centaur" memory buffers, this will not give any tangible performance boost, but it means that the servers are making use of the most popular and thus cheapest server memory technology.

The 2U S822LC "Big Data" looks like a solid offering. Pricing starts at $5999 (one 3.3 GHz 8-core, 64 GB RAM, no GPU), but realistically a full equipped server (two 10-cores, one K80, 128 GB) is around $16000. If you do not need the GPU, a server with two 10-cores, 256 GB, 2x 10 GB and two 1 TB disks costs around $13341. The CPU inside is still the 190W TDP single chip 10-core (at 2.9-3.5 GHz boost) that we tested a while ago. There is also an 8-core (3.3 - 3.7 GHz boost) alternative.

The 1U S821LC starts at $5900. The 1U form factor limits the POWER8 to much lower power envelopes. The 8-core chip runs at 2.3 GHz (135W TDP), the 10-core is allowed to consume a greater 145W, but runs at a meager – for POWER8 standards – 2.1 GHz. We can imagine that this is indeed based upon the customer feedback of space constrained datacenters, as IBM claims. We feel however that it makes the S821LC server less attractive as one of the distinguishing features of the POWER8 is the high single threaded performance. The POWER8 was simply not designed to run inside a 1U server. On the other side of the coin, a 2.1 GHz 10-core might still be fast enough to feed the GPU with the necessary data in some HPC applications.

IBM's OpenPOWER efforts Future Visions: POWER8 with NVLink
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  • loa - Monday, September 19, 2016 - link

    This article neglects one important aspect to costs:
    per-core licensed software.
    Those licenses can easily be north of 10 000$ . PER CORE. For some special purpose software the license cost can be over 100 000 $ / core. Yes, per core. It sounds ridiculous, but it's true.
    So if your 10-core IBM system has the same performance as a 14-core Intel system, and your license cost is 10 000$ / core, well, then you just saved yourself 40 000 $ by using the IBM processor.
    Even with lower license fee / core, the cost advantage can be significant, easily outweighing the additional electricity bill over the lifetime of the server.
  • aryonoco - Tuesday, September 20, 2016 - link

    Thanks Johan for another very interesting article.

    As I have said before, there is literally nothing on the web that compares with your work. You are one of a kind!

    Looking forward to POWER 9. Should be very interesting.
  • HellStew - Tuesday, September 20, 2016 - link

    Good article as usually. Thanks Johan.
    I'd still love to see some VM benchmarks!
  • cdimauro - Wednesday, September 21, 2016 - link

    I don't know how much value could have the performed tests, because they don't reflect what happens in the real world. In the real world you don't use an old o.s. version and an old compiler for an x86/x64 platform, only because the POWER platform has problems with the newer ones. And a company which spends so much money in setting up its systems, can also spend just a fraction and buy an Intel compiler to squeeze out the maximum performance.
    IMO you should perform the tests with the best environment(s) which is available for a specific platform.
  • JohanAnandtech - Sunday, September 25, 2016 - link

    I missed your reaction, but we discussed this is in the first part. Using Intel's compiler is good practice in HPC, but it is not common at all in the rest of the server market. And I do not see what an Intel compiler can do when you install mysql or run java based applications. Nobody is running recompiled databases or most other server software.
  • cdimauro - Sunday, October 2, 2016 - link

    Then why you haven't used the latest available distro (and compiler) for x86? It's the one which people usually use when installing a brand new system.
  • nils_ - Monday, September 26, 2016 - link

    This seems rather disappointing, and with regards to optmized Postgres and MariaDB, I think in that case one should also build these software packages optimized for Xeon Broadwell.
  • jesperfrimann - Thursday, September 29, 2016 - link

    Optimized for.. simply means that the software has been officially ported to POWER, and yes that would normally include that the specific accelerators that are inside the POWER architecture now are actually used by the software, and this usually means changing the code a bit.
    So .. to put it in other words .. just like it is with Intel x86 Xeons.

    // Jesper
  • alpha754293 - Monday, October 3, 2016 - link

    I look forward to your HPC benchmarks if/when they become available.

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