Bulldozer for Servers: Testing AMD's "Interlagos" Opteron 6200 Series
by Johan De Gelas on November 15, 2011 5:09 PM ESTPower Management in Windows Server 2008 SP2
Enabling the C-states in ESX 5i might bring the Opteron 6276 an improved performance/watt ratio. The question is whether the low power consumption at light loads will negate the performance impact. Although power consumption is lowered by using the "C-state enable" tweak, it is not spectacular: 10% lower energy consumption in idle will probably not give the Opteron 6276 an amazing performance/watt ration in ESXi. The impact of this tweak will make a difference in our EWL testing, not in the "full speed ahead" benchmarks. Also, our vApus FOS EWL testing showed that the Xeon consumed 25% less energy, so it will remain ahead.
As the virtualization benchmarks require more time to run, we will have to delay investigating them for a later article. But what about Windows 2008 R2? The idle power of the Opteron 6276 was excellent there. So which power policy should be chosen in Windows 2008? We compared Opteron performance in "High performance" to the Opteron 6276 performance when the power management policy was set to "Balanced.
|
Opteron 6276 "High Performance" |
Opteron 6276 "High Performance" + C6 enable. |
Xeon X5670 "High performance" vs. Xeon X5670 "Balanced" |
|
| Cinebench Single-threaded | +16% | +18% | +1% |
| Cinebench Multi-threaded | +5% | +5% | +1% |
| Blender | +4% | +13% | +1% |
| Encryption/Decryption AES | +43% / +42% | +43% / +44% | +28% / +28% |
| Encryption/Decryption Twofish/Serpent | +8% / +8% | +8 / +8% | +0 / +0% |
| Compression/decompression | +9% / +4% | +9 / +4% | +0 / +2% |
If we combine the our idle power consumption measurements with these numbers, things get a lot clearer. The "balanced" power policy disables turbo. Therefore, the maximum performance boost from enabling "high performance" should be 13%. The TrueCrypt benchmarks show much larger increases (see (*)), which we honestly don't understand. The performance boost (40%) is only possible if the CPU boosts to 3.2GHz, but that is not supposed to happen. First, the TrueCrypt software is well threaded and uses all clusters (32 threads). Second, we disabled C6, so normally the CPU is not able to boost to 3.2GHz. Third, our monitoring clearly indicated a 2.6GHz clock as expected.
We also did a quick x264 4.0 benchmark (1st pass) which is lightly threaded and showed the same performance (46%!) increase by simply switching from "Balanced" to "High performance" (turbo limited to 2.6GHz, no C6). The Xeon only got a 13% increase in performance..
Closer monitoring reveals that "Balanced" frequently reduces the cores to 1.4GHz. So we have a similar situation as the one where we found power management problems on the AMD "Istanbul" Opteron when the power policy was set to "Balanced".
Basically "Balanced" brings the clock speed down to a low P-state even when a thread is demanding the maximum processing power. Or in other words, the power manager is too eager to bring the clock speed down instead of looking ahead: the polling is blind for the very near future. The result is that quite often the workload gets processed at 1.4GHz (for a short time).
In contrast, the high performance setting does not make use of frequency scaling besides Turbo. So the CPU runs at 2.3GHz at the very minimum and frequently reaches 2.6GHz. So if you buy an Opteron 6200 server, it is strongly advised to chose the "High Performance" setting. Under light load, the balanced power manager saves a few percentage of power running idle, but in our opinion, it is not worth the large performance degradation. Notice also that the Xeon hardly suffers from the same problem with the exception of the AES-NI enabled TrueCrypt bench, and even then the performance impact is significantly lower.
In a nutshell: the power policy "Balanced" strongly favors the Xeon as the performance impact is non-existent or much lower. Let us see some raw performance numbers.
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zappb - Tuesday, November 29, 2011 - link
Thanks Johan for the ungodly amount of time you and your team spent on this review, also thanks to all contributors to the comments which was very useful to get more context to someone like myself who is not very up to speed with server tech.The 45 Watt and 65 watt Opterons not mentioned on the front page of the article (but mentioned in the comments - are these based on Interlagos?)
To me it looks like a big win for AMD - and these benchmarks are are not even optimised for the architecture (Linux kernel 3 was not used - can't wait to see updated benchmarks, something like FreeBSD or when we get an updated scheduler for the windows server OS's...should make a big difference.
Really low idle power consumption is nice, and Im planning to pick one of these up (for home use) to play around with FreeBSD, vm's, etc...just for training purposes,
The other point about Intel's sandybridge Xeons, these are just going to be 8 core 3960x right? Which may not change the current server landscape very much depending on their prices.
JWesterby - Friday, February 10, 2012 - link
Respect is due, Johan! You did a very useful review under significant limitations. The very best part is to point an unbiased light at a damned interesting CPU. There is an important "next step," which I will address shortly.As always, just the mention of AMD brings out hysterical attacks. One would think we were talking about Stem Cell research!! There is no real discussion -- it's pitchforks, lit torches, and a stake ready for poor Johan and anyone else ready and willing to consider the mere possibility that AMD have produced worthy technology!!
Computer technology - doing it, anyway - has changed. It's become ALL about the bloody money, and the "culture" of the people doing technology has also changed -- it has become much more cut-throat, there is far less collegiality, and the number of people willing to take risks on projects has become really uncommon. Qualified people doing serious technology just because they can is uncommon.
There is no end to posers (including some on this board), Machiavellian Fortune 500 IT managers, and "Project Managers" who are clueless (there ARE some great IT managers and wonderful PM's but their numbers are shrinking). My hat to those in Open Source - they are the Last Bastion of decency for the sake of decency, and technology merely for the joy of doing it !!
"Back in the day" people seemed really into the technology, solving difficult problems, and making good things happen. There was truly a culture. For example not taking a moment to help someone on the team or otherwise made you a jerk. Development was a craft or an art, and we were all in it together. We are loosing that, and it's become more dog-eat-dog with a kind of mean spirit. What a shame. Many of the comments here are perfect examples -- people who would rather burn down the temple than give a new and challenging technology a good think.
Personally I can't wait to get my hands on a couple of AMD's new CPU's, build a decent server, and carefully work out the issues with patience. These new Opterons are like a whole new tech that may be the beginning of all new territory.
My passion and some professional work is coding at the back end in C/C++ and I'm just beginning to understand CUDA and using GPU's to beef up parallel code. My work is all around (big) data warehousing, cutting edge columnar databases, almost everything running virtual, all the way through to analytics on BI platforms. I do all of that both on MS Server 2008, Solaris and FreeBSD. All that is a perfect environment to test AMD's "new territory."
Probably worth a blog at some point because these processors are new territory and using them well will take some work just keeping track of all the small things that shake out. That's the "next step" that this and other reviews require to really understand AMD's Bulldozers. Doing that well, if AMD is right with these chips, means being able to build some great back-end servers at a much more approachable price; more importantly without paying an "Intel" tax, and in the end having two strong vendors and thereby more freedom to make the best choice for the requirement.
PhotoPrint - Sunday, December 25, 2011 - link
you should make fair comparison at the same price range!lts like comparing GTX580 VS AMD RADEON 6950!
g101 - Wednesday, January 11, 2012 - link
Wow, anad let the truth about bulldozer leak out.ppennisi - Wednesday, March 7, 2012 - link
To obtain maximum performance from my Dell R715 server equipped with dual Interlagos processor I had to DISABLE C1E in the BIOS.Under VMware the machines performance changed completely, almost doubled in performance.
Maybe you should try it.
anti_shill - Monday, April 2, 2012 - link
Here's a more accurate reflection of Bulldozer/ interlagos performance, untainted by intel ad bucks...http://www.phoronix.com/scan.php?page=article&...
But if u really want to see what the true story is, have a look at AMD's stock price lately, and their server wins. They absolutely smoke intel on virtualization, and anything that requires a lot of threads. It's not even close. That would be the reason this review pits Interlagos against an Intel processor that costs twice as much.