Calxeda's ARM server tested
by Johan De Gelas on March 12, 2013 7:14 PM EST- Posted in
- IT Computing
- Arm
- Xeon
- Boston
- Calxeda
- server
- Enterprise CPUs
Measuring Bandwidth
Stream measures "sustainable memory bandwidth" and is thus a good indication of how a CPU will handle data intensive applications. Dr. John McCalpin is the developer and maintainer of the STREAM benchmark.
We compiled with gcc 4.7 on all platforms and used the -O3 -fopen -static settings. It is important to remark that this version of gcc has been optimized by the Linaro group, a non-profit software engineering effort. Linaro's objective is to optimize the kernel and typical tools for the ARM-Cortex A-series CPUs.
On the Intel CPUs we force the threads to make use of Hyper-Threading with taskset. So for example, the four threads measurement is done on two physical cores with four threads. This gives an idea of how a quad-core ARM server node compares to a virtual machine that gets a few physical and few logical cores from the hypervisor. It also allows us to evaluate how two threads on top of an Atom core compare to two ARM cores. When you compare CPUs with similar power consumption, you typically get two ARM cores for each Hyper-Threaded Atom core.
The ARM based server is a pretty bad choice right now for memory intensive workloads. Even with four cores and DDR3-1333, the useable bandwidth is less than one sixth of what one Xeon core can sustain.
In a similar vein, the ECX-1000 is not capable of providing more bandwidth than an Atom system equipped with DDR2-667. However, both the Atom and ARM cores are pretty bad when it comes to bandwidth. Although the specs claim that the CPUs can drive one channel of DDR3-1066, the measured bandwidth comes nowhere near the theoretical 8.5GB/s that such a DIMM can deliver.
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JohanAnandtech - Wednesday, March 13, 2013 - link
Thanks!SunLord - Wednesday, March 13, 2013 - link
Hmm if these didn't cost $20,000 they would make a nice front end for larger websites and forums using less rack space and power. What setup using these would you use for anandtech? Would you guys keep the intel DB server?Gunbuster - Wednesday, March 13, 2013 - link
I just got a Dell R720xd decked out with 384GB and 4.3TB of storage for a hair over that price.JohanAnandtech - Wednesday, March 13, 2013 - link
Intel Xeons are still by far a better choice for relational databases that are very hard to split up (sharding is only a last resort)zachj - Wednesday, March 13, 2013 - link
I'm not sure I agree with the absolutism that seems imlicit in your comment that Xeons are better for relational databases...I think there are cases where that won't be true.Database scale-out doesn't always require sharding...using any of a number of different off-the-shelf capabilities built right into most SQL engines, you can create multiple active replicas of your database. This is generally better-suited to workloads that aren't write-intensive, but both clustering and replication allow for writes. While this may seem like a quick-and-dirty solution that is architecturally "less good" than sharding, hardware is a lot cheaper than paying people to design a sharding solution and the dollars very often drive the conversation. As long as the database size isn't terribly large this can be a very cost-effective way to scale out a database.
I would wager that the Anandtech website database (not the forum database) would probably be well-suited to this type of scale-out. You do waste some money on redundant storage but you more than make up for that cost by not having to pay a development team to implement sharding. If the comments section of the Anandtech website gets stored in the same underlying database, the size constraints and the write activity may appear to be incompatible with this approach, but I would in fact argue that comments don't require relational capabilities of SQL and would be more rightly stored as blobs in Hadoop or Azure Storage Tables. Then the Anandtech database is strictly articles and is both much more compact and almost entirely read-only (except for a few new articles per day).
rwei - Friday, March 15, 2013 - link
To the best of my understanding, replication does well for scaling reads but doesn't do much for writes. I'd still imagine that this would work decently well with AnandTech, where I can't see the volume of writes being that large relative to the volume of reads.Kurge - Wednesday, March 13, 2013 - link
They would make a horrible front end for such websites. Just buy a single Xeon server and don't artificially limit it by using 24 VMs. Just run the app straight on the metal and it will perform massively better.Oldboy1948 - Wednesday, March 13, 2013 - link
Very interesting Johan as your tests often are!Interesting that the memory bw is so much lower than anything from Intel. In fact Iphone 5 looks much better...why? Only Intel has about the same rsults in compress and decompress.
JohanAnandtech - Wednesday, March 13, 2013 - link
Where did you see the stream results on the A6? I might have missed it somewhere. The only ones I could find reported only 1 GB/s in Triad. http://www.anandtech.com/show/6298/analyzing-iphon... The Quad ECX-1000 got 1.8 GB/sPCTC2 - Wednesday, March 13, 2013 - link
Do you know what would be an interesting concept for a future version of these cluster-in-a-box systems? A solution like ScaleMP. ScaleMP is basically a reverse VM. A hypervisor on each server clusters together to run a single OS with an aggregation of all resources (cores, RAM, network, and disk). ScaleMP running on 4x Dual-socket 8-core Xeon systems w/ 32GB RAM results in a usable system with 64-cores and 128GB RAM as if it was running natively on the hardware. This would be an interesting concept to transfer to the ARM space (if a form of hardware virtualization ever is designed). In a box like this, there would be 192 cores and 192GB of RAM available to a single Fedora instance. Cluster 2 of these together and suddenly there's a system with 384 cores and 384GB of RAM in 4U. Just some food for thought.