Assessing IBM's POWER8, Part 2: Server Applications on OpenPOWER
by Johan De Gelas on September 15, 2016 8:01 AM ESTEnergy Consumption
A large part of the server market is very sensitive to performance-per-watt. That includes the cloud vendors/hosts. For a smaller part of the market, top performance is more important than the performance/watt ratio. Indeed, for financial trading, big data analyses, large databases, and most HPC servers, total performance is the top priority. Energy consumption should not be outrageous, but it is not the most important concern.
We tested the energy consumption of our servers for a one-minute period in several situations. The first one is the point where the tested server performs best in MySQL: the highest throughput just before the response time goes up significantly. Then we look at the point where throughput is the highest (no matter what response time). This is the situation where the CPU is fully loaded.
| SKU | TDP (on paper) spec |
Idle Server W |
MySQL Best Throughput at Lowest Resp. Time (W) |
MySQL Max Throughput (W) |
Transaction /s |
Tr/watt |
| IBM POWER8 S812LC | 190 W | 221 | 259 | 260 | 14482 | 55 |
| Xeon E5-2699 v4 | 145 W | 67 | 213 | 235 | 18997 | 89 |
| Xeon E5-2690 v3 | 135 W | 84 | 249 | 254 | 11741 | 47 |
Throughput and single threaded performance were the priorities for designing POWER8. Power consumption stood probably much lower on the list, way behind RAS. The idle power shows us that you should not use the POWER8 in applications that run at low load for long periods.
Intel's "Broadwell-EP" (Xeon E5 v4), by comparison, is the clear victor when it comes to performance per watt, and even without looking at Intel's background, it's clear from the data alone that more thought was put into that aspect.
However, considering that the POWER8 was launched around the same time as Intel Haswell, IBM's multicore delivers a lot of integer performance per watt of energy it consumes. In fact, despite the power gobbling Centaur chips, despite the fact that MySQL is not the most POWER8 optimized application, IBM's medium range POWER8 is capable of defeating Intel's Haswell. While this is less relevant to the server buyer today, it does show that IBM's engineering capabilities are competitive with Intel, which is good news for the upcoming POWER9 chip. The POWER9 chip will be the first POWER chip which has specific SKUs for the affordable scale out servers.
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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
@nils_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.