Assessing IBM's POWER8, Part 2: Server Applications on OpenPOWER
by Johan De Gelas on September 15, 2016 8:01 AM ESTClosing Thoughts: Microarchitecture
Wrapping things up, let's first look at the POWER8 from a microarchitectural point of view. The midrange POWER8 is able to offer significantly higher performance than the best midrange contemporary Xeon "Haswell-EP" E5s. Even the performance per watt can be quite good, but only in the right conditions (high average CPU load, complex workloads).
IBM's engineers got their act together in 2014. That might seem like a trivial thing to say, but "Netburst", "Bulldozer" and "Cell" designs show that building a balanced architecture is not an easy task.
Considering POWER8 Scale Out Servers
The performance data and analysis is all very interesting, but at the end of the day, what if you are a server buyer? The POWER8 servers are definitely not for everyone. For many people, the superior performance per watt ratio of the Xeon E5-2600 v4 is more attractive. In most virtualized environments, the CPU load is relatively low, and saving lots of power at low loads (at least 100W per socket) will keep the TCO a lot lower.
An – admittedly smaller – part of the market does not care that much about electricity bills, but rather favors performance per dollar. And in that case, the S812LC model that can use cheaper DIMMs to reach the same capacity (32 DIMMs slots instead of 16-24) combined with the relatively cheap POWER8 CPU can make sense. It is important to note that our benchmarks are definitely not the showcases. According to IBM, MariaDB and Postgres have been more optimized for the POWER8 than MySQL. In those cases, IBM claims up to 40% better performance than the Xeon E5-2690 v4.
Those IBM benchmarks show of course the POWER8 in the best light, but we feel we should not dismiss them, just take them with grain of salt. If you read our very first article about OpenPOWER on Linux, you will notice we had trouble getting many workloads to even run. Once we got it working, performance was suboptimal. Now, less than a year later, most of the performance problems have either vanished (MySQL, Spark) or improved a lot (OpenJDK). The OpenPOWER Linux ecosystem gets better at a very fast pace.
IBM asks $13141 for the S822LC ("for Big Data") which includes two 10-core POWER8s, 256 GB DRAM, two 1 TB disks. A similarly configured DELL R730 with Xeon E5-2680 v4 costs around $12-13k, a similar HP DL380 costs around $15-17k. Though it is admittedly debatable how large the price advantage is as the actual street prices are hard to determine. HP and IBM tend to give bigger discounts, but those discounts get smaller for the most affordable servers.
So although IBM will not convert the masses as the price advantage is not that large, the new POWER8 servers are competitively priced. The bottom line: the IBM POWER8 LC servers can offer you better performance per dollar than a similar x86 server. But it's not a guarantee; as a server buyer you have to do your research and check whether your application is among the POWER8 optimized ones, and what kind of CPU load profile your application has. The Intel Xeons, by comparison, require less research, and are much more "general purpose".
Meanwhile the most expensive of the new server models, the S822LC HPC with six quad port NVLINKs and four Tesla P100s, is unique in the HPC market. Given a workload that has real and meaningful bus bandwidth needs, and it is very likely that any Xeon server with 4 GPUs will have a lot of trouble competing with it.
Overall the new POWER8 servers are not a broad full scale attack on Intel's Xeon. Rather they are a potent attempt to establish some strong beachheads in a number of niche but key markets (GPU accelerated HPC, Big Data).
And looking towards the future, it's worth considering that the POWER9 will offer a scale out version without the expensive and power hogging memory buffers. With that in the works, it's clear that IBM and the members of the OpenPOWER foundations are definitely on the right track to grab a larger part of the server market.
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PowerOfFacts - Friday, September 16, 2016 - link
trollBOMBOVA - Friday, October 7, 2016 - link
Rich info , good scoutPowerOfFacts - Friday, September 16, 2016 - link
Sigh ....PowerOfFacts - Friday, September 16, 2016 - link
That's strange, this site says you can buy a POWER8 server for $4800. https://www.ibm.com/marketplace/cloud/big-data-inf...Screwed up Power (so many times)? Please explain? Compared to what....SPARC? Itanium? If you are talking about those platforms, POWER has 70% of that marketshare. Do you mean against "Good Enough" Intel? Absolutely Intel is the market leader but only in share as it isn't in innovation. Power still delivers enterprise features for AIX and IBM i customers with features Intel could only dream about. Where the future of the data center is going with Linux, well it did take IBM a while to figure out they couldn't do it their way. Now, they are committed 100% (from my perspective as a non-IBMer while also being committed to AIX & IBM i as their is a solid install base there) which we all see in the form of IBM & even non-IBM solutions built by OpenPOWER partners and ISV solutions using little endian Linux. Yes, there are some workloads that require extra work to optimize but for those already optimized or those which can be optimized, those customers can now buy a server for less money that has the potential to outperform Intel by up to 2X, in a system using innovative technology (CAPI & NVLink) that is more reliable. I don't know, IBM may be late and Power has some work to do but I really don't think you can back up your statement that "IBM has screwed up power so many times". Latest OpenPOWER Summit was a huge success. Here is a Google interview https://www.youtube.com/watch?v=f0qTLlvUB-s&fe...
Oh, but you were probably just trying to be clever and take a few competitive shots.
CajunArson - Saturday, September 17, 2016 - link
Yeah, that $4800 Power server wasn't nearly equivalent to what was benchmarked in this review with the "midrange" server that costs over $11K on the same web page you cited.I could build an 8 or 12 core Xeon that would put the hurt on that low-end Power box for less money and continue to save money during every minute of operation.
JohanAnandtech - Saturday, September 17, 2016 - link
" it will cost anywhere from 5-10X" . What do you base this on? Several SKUs of IBM are in the $1500 range. "Something like $10K for the processor". This seems to be about the high-end. The E7s are in the $4.6-7k range. Even if IBM would charge $10k for the high end CPUs, it is nowhere near being 5x more expensive. Unless I am missing something, you seem to have missed that IBM has a scale out range and is offering much more affordable OpenPOWER CPUs.jesperfrimann - Wednesday, September 21, 2016 - link
IMHO, the place where POWER servers make sense right now, is for use with IBM software. So if you are using something DB2 or WebSphere, where the real cost is the Software licenses.Then it's really a Nobrainer. Not that your local IBM sales Guy will like that you'll do a switch to a Linux@Power solution :)
// Jesper
YukaKun - Thursday, September 15, 2016 - link
For the Java tests, did you change the GC collector settings? Also, why only 24GB for the JVM? I run JBoss with 32GB across our servers. I'd use more, but they still have issues with going to higher levels.Cheers!
madwolfa - Thursday, September 15, 2016 - link
Unless working with huge datasets you want to keep your JVM heap size as reasonably low as possible... otherwise there would be a penalty on GC performance. Granted, with this sort of hardware it would be pretty minuscule, but the general rule of thumb still applies...JohanAnandtech - Thursday, September 15, 2016 - link
No changes to the GC Collector settings. 24 GB for VM = 4x 24 GB + 4x 3 GB for Transaction Injector and 2 GB for the controllor = +/- 110 GB memory. We wanted to run it inside 128 GB as most of our DIMMs are 16 GB at DDR4-2400/2133.