Intel Xeon E5 Version 3: Up to 18 Haswell EP Cores
by Johan De Gelas on September 8, 2014 12:30 PM ESTWebsite Performance: Drupal 7.21
While there are few web servers that actually need such processing behemoths, we decided to go ahead and test in this area, just for the sake of satifying our curiosity. Most websites are based on the LAMP stack: Linux, Apache, MySQL, and PHP. Few people write HTML/PHP code from scratch these days, so we turned to running a Drupal 7.21 based site. The web server is Apache 2.4.7 and the database is MySQL 5.5.38 on top of Ubuntu 14.04 LTS.
Drupal powers massive sites like The Economist and MTV Europe and has a reputation of being a hardware resources hog. That is a price more and more developers pay happily for lowering the time to market for their work. We tested the Drupal website with our vApus stress testing framework and increased the number of connections from 5 to 1500.
First we report the maximum throughput achievable with 95% percent of requests being handled faster than 100 ms. It is important to note that there's a chance that a user experiences a much slower response time on a request, which could be much longer than 100 ms. Also, as each page view consists of many requests, there's an increased chance that one of the "slow responses" is among them. So the average response time is definitely a very bad indicator of user experience, and ensuring the 95% percentile is still fast enough is a lot safer.
In the case of our Drupal testing, the new Haswell EP Xeons definitely take the lead, but at the top of the stack we don't see a lot of scaling with additional cores – the E5-2699 v3 and the E5-2695 v3 deliver nearly the same result. There are several reasons for this. The first is that the database of our current test website is too small. The second is that we still need to fine tune the configuration of our website to scale better with such high core counts.
We'll remedy this in the future as we adapt our tuning. Right now, it seems that we get good scaling up to 24 physical cores, but beyond that our tuning probably needs more work. Nevertheless, we felt we should share this result as most website owners do not have a specialized "make it scale" engineering team like Google and Facebook. And yes, it is probably better to load balance your website over several smaller nodes.
Still, the results are quite interesting. It looks like the new Xeon v3 scales better. The Xeon E5-2690 has no trouble keeping up – thanks to its higher clock speed – with the Ivy Bridge EP Xeon, which features a higher core count. The Xeon E5-2650L v3 has a lower clock speed but is able to use its higher core count to perform better. One of the reasons might be the fact that synchronization latency has been significantly improved.
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LostAlone - Saturday, September 20, 2014 - link
Given the difference in size between the two companies it's not really all that surprising though. Intel are ten times AMD's size, and I have to imagine that Intel's chip R&D department budget alone is bigger than the whole of AMD. And that is sad really, because I'm sure most of us were learning our computer science when AMD were setting the world on fire, so it's tough to see our young loves go off the rails. But Intel have the money to spend, and can pursue so many more potential avenues for improvement than AMD and that's what makes the difference.Kevin G - Monday, September 8, 2014 - link
I'm actually surprised they released the 18 core chip for the EP line. In the Ivy Bridge generation, it was the 15 core EX die that was harvested for the 12 core models. I was expecting the same thing here with the 14 core models, though more to do with power binning than raw yields.I guess with the recent TSX errata, Intel is just dumping all of the existing EX dies into the EP socket. That is a good means of clearing inventory of a notably buggy chip. When Haswell-EX formally launches, it'll be of a stepping with the TSX bug resolved.
SanX - Monday, September 8, 2014 - link
You have teased us with the claim that added FMA instructions have double floating point performance. Wow! Is this still possible to do that with FP which are already close to the limit approaching just one clock cycle? This was good review of integer related performance but please combine with Ian to continue with the FP one.JohanAnandtech - Monday, September 8, 2014 - link
Ian is working on his workstation oriented review of the latest XeonKevin G - Monday, September 8, 2014 - link
FMA is common place in many RISC architectures. The reason why we're just seeing it now on x86 is that until recently, the ISA only permitted two registers per operand.Improvements in this area maybe coming down the line even for legacy code. Intel's micro-op fusion has the potential to take an ordinary multiply and add and fuse them into one FMA operation internally. This type of optimization is something I'd like to see in a future architecture (Sky Lake?).
valarauca - Monday, September 8, 2014 - link
The Intel compiler suite I believe already convertsx *= y;
x += z;
into an FMA operation when confronted with them.
Kevin G - Monday, September 8, 2014 - link
That's with source that is going to be compiled. (And don't get me wrong, that's what a compiler should do!)Micro-op fusion works on existing binaries years old so there is no recompile necessary. However, micro-op fusion may not work in all situations depending on the actual instruction stream. (Hypothetically the fusion of a multiply and an add in an instruction stream may have to be adjacent to work but an ancient compiler could have slipped in some other instructions in between them to hide execution latencies as an optimization so it'd never work in that binary.)
DIYEyal - Monday, September 8, 2014 - link
Very interesting read.And I think I found a typo: page 5 (power optimization). It is well known that THE (not needed) Haswell HAS (is/ has been) optimized for low idle power.
vLsL2VnDmWjoTByaVLxb - Monday, September 8, 2014 - link
Colors or labeling for your HPC Power Consumption graph don't seem right.JohanAnandtech - Monday, September 8, 2014 - link
Fixed, thanks for pointing it out.