Real-world virtualization benchmarking: the best server CPUs compared
by Johan De Gelas on May 21, 2009 3:00 AM EST- Posted in
- IT Computing
Caches, Memory Bandwidth, or Pure Clock Speed?
We currently only have one Xeon 55xx in the lab, but we have four different CPUs based on the AMD "K10" architecture. That allows us to do some empirical testing to find out what makes the most impact: larger caches, faster memory, or mostly clock speed?
Every bit of extra clock speed seems to benefit our test. Bandwidth has a smaller effect. Even if we reduce the bandwidth of the Shanghai Opteron by one third, the score only lowers by 6%. Given that we only run four VMs this seems reasonable. Shanghai got three times as much L3 cache, a faster L3 cache, DDR2-800 instead of DDR2-667, and lower world switch times. The Opteron 2377 2.3GHz allows us to test at the same clock speed: the Shanghai Opteron is about 9.5% faster clock-for-clock than the Barcelona chip. If we run both chips with the same memory, the Shanghai Opteron is 6.5% faster. That's a small difference, but the Opteron EE promises much lower power consumption (40W ACP, 60W TDP) than the Barcelona chip (75W ACP, 115W TDP).
Notice that the Dual Opteron is a lot more bandwidth sensitive: improve bandwidth by 20% and you get 14% higher performance. Four VMs are fighting for only 4x1MB of cache, while running on the dual "Shanghai" Opteron each VM in theory has two 512KB L2 caches plus a 3MB chunk of L3.
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Bandoleer - Thursday, May 21, 2009 - link
I have been running Vmware Virtual Infrastructure for 2 years now. While this article can be useful for someone looking for hardware upgrades or scaling of a virtual system, CPU and memory are hardly the bottlenecks in the real world. I'm sure there are some organizations that want to run 100+ vm's on "one" physical machine with 2 physical processors, but what are they really running????The fact is, if you want VM flexability, you need central storage of all your VMDK's that are accessible by all hosts. There is where you find your bottlenecks, in the storage arena. FC or iSCSI, where are those benchmarks? Where's the TOE vs QLogic HBA? Considering 2 years ago, there was no QLogic HBA for blade servers, nor does Vmware support TOE.
However, it does appear i'll be able to do my own baseline/benching once vSphere ie VI4 materializes to see if its even worth sticking with vmware or making the move to HyperV which already supports Jumbo, TOE iSCSI with 600% increased iSCSI performance on the exact same hardware.
But it would really be nice to see central storage benchmarks, considering that is the single most expensive investment of a virtual system.
duploxxx - Friday, May 22, 2009 - link
perhaps before you would even consider to move from Vmware to HyperV check first in reality what huge functionality you will loose in stead of some small gains in HyperV.ESX 3.5 does support Jumbo, iscsi offload adapters and no idea how you are going to gain 600% if iscsi is only about 15% slower then FC if you have decent network and dedicated iscsi box?????
Bandoleer - Friday, May 22, 2009 - link
"perhaps before you would even consider to move from Vmware to HyperV check first in reality what huge functionality you will loose in stead of some small gains in HyperV. "what you are calling functionality here are the same features that will not work in ESX4.0 in order to gain direct hardware access for performance.
Bandoleer - Friday, May 22, 2009 - link
The reality is I lost around 500MBps storage throughput when I moved from Direct Attached Storage. Not because of our new central storage, but because of the limitations of the driver-less Linux iSCSI capability or the lack there of. Yes!! in ESX 3.5 vmware added Jumbo frame support as well as flow control support for iSCSI!! It was GREAT, except for the part that you can't run JUMBO frames + flow control, you have to pick one, flow control or JUMBO.I said 2 years ago there was no such thing as iSCSI HBA's for blade servers. And that ESX does not support the TOE feature of Multifunction adapters (because that "functionality" requires a driver).
Functionality you lose by moving to hyperV? In my case, i call them useless features, which are second to performance and functionality.
JohanAnandtech - Friday, May 22, 2009 - link
I fully agree that in many cases the bottleneck is your shared storage. However, the article's title indicated "Server CPU", so it was clear from the start that this article would discuss CPU performance."move to HyperV which already supports Jumbo, TOE iSCSI with 600% increased iSCSI performance on the exact same hardware. "
Can you back that up with a link to somewhere? Because the 600% sounds like an MS Advertisement :-).
Bandoleer - Friday, May 22, 2009 - link
My statement is based on my own experience and findings. I can send you my benchmark comparisons if you wish.I wasn't ranting at the article, its great for what it is, which is what the title represents. I was responding to this part of the article that accidentally came out as a rant because i'm so passionate about virtualization.
"What about ESX 4.0? What about the hypervisors of Xen/Citrix and Microsoft? What will happen once we test with 8 or 12 VMs? The tests are running while I am writing this. We'll be back with more. Until then, we look forward to reading your constructive criticism and feedback.
Sorry, i meant to be more constructive haha...
JohanAnandtech - Sunday, May 24, 2009 - link
"My statement is based on my own experience and findings. I can send you my benchmark comparisons if you wish. "Yes, please do. Very interested in to reading what you found.
"I wasn't ranting at the article, its great for what it is, which is what the title represents. "
Thx. no problem...Just understand that these things takes time and cooperation of the large vendors. And getting the right $5000 storage hardware in lab is much harder than getting a $250 videocard. About 20 times harder :-).
Bandoleer - Sunday, May 24, 2009 - link
I haven't looked recently, but high performance tiered storage was anywhere from $40k - $80k each, just for the iSCSI versions, the FC versions are clearly absurd.solori - Monday, May 25, 2009 - link
Look at ZFS-based storage solutions. ZFS enables hybrid storage pools and an elegant use of SSDs with commodity hardware. You can get it from Sun, Nexenta or by rolling-your-own with OpenSolaris:http://solori.wordpress.com/2009/05/06/add-ssd-to-...">http://solori.wordpress.com/2009/05/06/add-ssd-to-...
pmonti80 - Friday, May 22, 2009 - link
Still it would be interesting to see those central storage benchmarks or at least knowing if you will/won't be doing them for whatever reason.