Assessing IBM's POWER8, Part 1: A Low Level Look at Little Endian
by Johan De Gelas on July 21, 2016 8:45 AM ESTBenchmark Selection
Our testing was conducted on Ubuntu Server 15.10 (kernel 4.2.0) with gcc compiler version 5.2.1.
The choice of comparing the IBM POWER8 2.92 10-core with the Xeon E5-2699 v4 22-core might seem weird, as the latter is three-times as expensive as the former. However, for this review, where we evaluate single thread/core performance, pricing does not matter. As this is one of the lowest clocked POWER8 CPUs, an Intel Xeon with a high base clock - something that's common for Intel's chips with fewer cores - would make it harder to compare the two microarchitectures. We also wanted an Intel chip that could reach high turbo clockspeeds thanks to a high TDP.
And last but not least we did not have very many Xeon E5 v4 SKUs in the lab...
Configuration
IBM S812LC (2U)
The IBM S812LC is based up on Tyan's "Habanero" platform. The board inside the IBM server is thus designed by Tyan.
| CPU | One IBM POWER8 2.92 GHz (up to 3.5 GHz Turbo) |
| RAM | 256 GB (16x16GB) DDR3-1333 |
| Internal Disks | 2x Samsung 850Pro 960 GB |
| Motherboard | Tyan SP012 |
| PSU | Delta Electronics DSP-1200AB 1200W |
Intel's Xeon E5 Server – S2600WT (2U Chassis)
This is the same server that we used in our latest Xeon v4 review.
| CPU |
Xeon E5-2699 v4 |
| RAM | 256 GB (8x32GB) Samsung DDR4-2400 |
| Internal Disks | 2x Samsung 850Pro 960 GB |
| Motherboard | Intel Server Board Wildcat Pass |
| PSU | Delta Electronics 750W DPS-750XB A (80+ Platinum) |
Hyperthreading, Turbo, C1 and C6 were enabled in the BIOS.
Other Notes
All servers are fed by a standard European 230V (16 Amps max.) power line. The room temperature is monitored and kept at 23°C by our Airwell CRACs in our Sizing Servers Lab.
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jospoortvliet - Tuesday, July 26, 2016 - link
The point Johan makes is that his goal is not to get the best bechmark scores but the most relevant real life data. One can argue if he succeeded, certainly the results are interesting but there is much more to the CPU's as usual. And I do think his choice is justified, while much scientific code would be recompiled with a faster compiler (though the cost of ICC might be a problem in a educational setting), many businesses wouldn't go through that effort.I personally would love to see a newer Ubuntu & GCC being used, just to see what the difference is, if any. The POWER ecosystem seems to evolve fast so a newer platform and compiler could make a tangible difference.
But, of course, if you in your usecase would use ICC or xLC, these benches are not perfect.
Eris_Floralia - Friday, July 22, 2016 - link
Are these two processor both tested at the same frequency？or at their stock clock？tipoo - Friday, July 22, 2016 - link
The latter, page 52.92-3.5 GHz vs 2.2-3.6 GHz
abufrejoval - Thursday, August 4, 2016 - link
Well since Johan really only tested one core on each CPU, it would have been nice to have him verify the actual clock speed of those cores. You'd assume that they'd be able to maintain top speed for any single core workload independent of the number of threads, but checking is better than guessing.roadapathy - Friday, July 22, 2016 - link
22nm? *yawwwwwwwwwn* Come on IBM, you can do better than that, brah.Michael Bay - Saturday, July 23, 2016 - link
Nope, 22 is the best SOI has right now. You have to remember it`s nowhere near standard litographies customer-wise.tipoo - Monday, July 25, 2016 - link
In addition to what Michael Bay (lel) said, remember that only Intel really has 14nm, when TSMC and GloFlo say 14/16nm they really mean 20nm with finfetts.feasibletrash0 - Saturday, July 23, 2016 - link
using a less capable compiler (GCC) to test a chip, and not using everything the chip has to offer seems incredibly flawed to me, what are you testing exactlyaryonoco - Saturday, July 23, 2016 - link
He's testing what actual software people actually run on these things.On your typical Linux host, pretty most everything is compiled with GCC. You want to get into exotic compilers? Sure both IBM and Intel have their exotic proprietary costly compilers, so what. Very few people outside of niche industries use them.
You want to compare a CPU with CPU? You keep the compiler the same. That's just common sense. It's also how the scientific method works!
feasibletrash0 - Sunday, July 24, 2016 - link
right, but you're comparing, say 10% of the silicon on that chip, and saying that the remaining 90% of the transistors making the chip does not matter, they do; if the software is not using them, that's fine, but it's not an accurate comparison of the hardware, it's a comparison of the software