Sizing Up Servers: Intel's Skylake-SP Xeon versus AMD's EPYC 7000 - The Server CPU Battle of the Decade?
by Johan De Gelas & Ian Cutress on July 11, 2017 12:15 PM EST- Posted in
- CPUs
- AMD
- Intel
- Xeon
- Enterprise
- Skylake
- Zen
- Naples
- Skylake-SP
- EPYC
Multi-core SPEC CPU2006
For the record, we do not believe that the SPEC CPU "Rate" metric has much value for estimating server CPU performance. Most applications do not run lots of completely separate processes in parallel; there is at least some interaction between the threads. But since the benchmark below caused so much discussion, we wanted to satisfy the curiosity of our readers.
Does the EPYC7601 really have 47% more raw integer power? Let us find out. Though please note that you are looking at officially invalid base SPEC rate runs, as we still have to figure out how to tell the SPEC software that our "invalid" flag "-Ofast" is not invalid at all. We did the required 3 iterations though.
| Subtest | Application type | Xeon E5-2699 v4 @ 2.8 |
Xeon 8176 @ 2.8 |
EPYC 7601 @2.7 |
EPYC Vs Broadwell EP |
EPYC vs Skylake SP |
| 400.perlbench | Spam filter | 1470 | 1980 | 2020 | +37% | +2% |
| 401.bzip2 | Compression | 860 | 1120 | 1280 | +49% | +14% |
| 403.gcc | Compiling | 960 | 1300 | 1400 | +46% | +8% |
| 429.mcf | Vehicle scheduling | 752 | 927 | 837 | +11% | -10% |
| 445.gobmk | Game AI | 1220 | 1500 | 1780 | +46% | +19% |
| 456.hmmer | Protein seq. analyses | 1220 | 1580 | 1700 | +39% | +8% |
| 458.sjeng | Chess | 1290 | 1570 | 1820 | +41% | +16% |
| 462.libquantum | Quantum sim | 545 | 870 | 1060 | +94% | +22% |
| 464.h264ref | Video encoding | 1790 | 2670 | 2680 | +50% | -0% |
| 471.omnetpp | Network sim | 625 | 756 | 705 (*) | +13% | -7% |
| 473.astar | Pathfinding | 749 | 976 | 1080 | +44% | +11% |
| 483.xalancbmk | XML processing | 1120 | 1310 | 1240 | +11% | -5% |
(*) We had to run 471.omnetpp with 64 threads on EPYC: when running at 128 threads, it gave errors. Once solved, we expect performance to be 10-20% higher.
Ok, first a disclaimer. The SPECint rate test is likely unrealistic. If you start up 88 to 128 instances, you create a massive bandwidth bottleneck and a consistent CPU load of 100%, neither of which are very realistic in most integer applications. You have no synchronization going on, so this is really the ideal case for a processor such as the AMD EPYC 7601. The rate test estimates more or less the peak integer crunching power available, ignoring many subtle scaling problems that most integer applications have.
Nevertheless, AMD's claim was not farfetched. On average, and using a "neutral" compiler with reasonable compiler settings, the AMD 7601 has about 40% (42% if you take into account that our Omnetpp score will be higher once we fixed the 128 instances issue) more "raw" integer processing power than the Xeon E5-2699 v4, and is even about 6% faster than the Xeon 8176. Don't expect those numbers to be reached in most real integer applications though. But it shows how much progress AMD has made nevertheless...
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tamalero - Tuesday, July 11, 2017 - link
How is that different if AMD ran stuff that is extremely optimized for them?Friendly0Fire - Tuesday, July 11, 2017 - link
That's kinda the point? You want to benchmark the CPUs in optimal scenarios, since that's what you'd be looking at in practice. If one CPU's weakness is eliminated by using a more recent/tweaked compiler, then it's not a weakness.coder543 - Tuesday, July 11, 2017 - link
Rather, you want to test under practical scenarios. Very few people are going to be running 17.04 on production grade servers, they will run an LTS release, which in this case is 16.04.It would be good to have benchmarks from 17.04 as another point of comparison, but given how many things they didn't have time to do just using 16.04, I can understand why they didn't use 17.04.
Santoval - Wednesday, July 12, 2017 - link
A compromise can be found by upgrading Ubuntu 16.04's outdated kernel. Ubuntu LTS releases include support for rolling HWE Stacks, which is a simple meta package for installing newer kernels compiled, modified, tested and packaged by the Ubuntu Kernel Team, and installed directly from the official Ubuntu repositories (not via a Launchpad PPA). With HWE 16.04 LTS can install up to the kernel of 18.04 LTS.I also use 16.04 LTS + HWE (it just requires installing the linux-generic-hwe-16.04 package), which currently provides the 4.8 kernel. There is even a "beta" version of HWE (the same package plus an -edge at the end) for installing the 4.10 kernel (aka the kernel of 17.04) earlier, which will normally be released next month.
I just spotted various 4.10 kernel listings after checking in Synaptic, so they must have been added very recently. After that there are two more scheduled kernel upgrades, as is shown in the following link. Of course HWE upgrades solely the kernel, it does not upgrade any application or any of the user level parts to a more recent version of Ubuntu.
https://wiki.ubuntu.com/Kernel/RollingLTSEnablemen...
CajunArson - Tuesday, July 11, 2017 - link
Considering the similarities between RyZen and Haswell (that aren't coincidental at all) you are already seeing a highly optimized set of RyZen results.But I have no problem seeing RyZen be tested with the newest distros, the only difference being that even Ubuntu 16.04 already has most of the optimizations for RyZen baked in.
coder543 - Tuesday, July 11, 2017 - link
What similarities? They're extremely different architectures. I can't think of any obvious similarities. Between the CCX model, caches being totally different layouts, the infinity fabric, Intel having better AVX-256/512 stuff (IIRC), etc.I don't think 16.04 is naturally any more optimized for Ryzen than it is for Skylake-SP.
CajunArson - Tuesday, July 11, 2017 - link
Oh please, at the core level RyZen is a blatant copy-n-paste of Haswell with the only exception being they just omitted half the AVX hardware to make their lives easier.It's so obvious that if you followed any of the developer threads for people optimizing for RyZen they say to just use the Haswell compiler optimizations that actually work better than the official RyZen optimization flags.
ddriver - Tuesday, July 11, 2017 - link
Can't tell if this post is funny or sad.CajunArson - Tuesday, July 11, 2017 - link
It's neither: It's accurate.Don't believe me? Look at the differences in performance of the holy 1800X over multiple Linux distros ranging from pretty new (OpenSuse Tumbleweed) to pretty old (Fedora 23 from 2015): http://www.phoronix.com/scan.php?page=article&...
Nowhere near the variation that we see with Skylake X since Haswell was already a solved problem long before RyZen lauched.
coder543 - Tuesday, July 11, 2017 - link
Right, of course. Ryzen is a copy-and-paste of Haswell.Don't make me laugh.