AmazonEC2ComputeUnit性能评测

使用以下命令测试CPU性能:
time echo "scale=5000; 4*a(1)" | bc -l -q

Intel(R) Core(TM) i5-2300 CPU @ 2.80GHz
cpu MHz         : 2884.687
cache size      : 6144 KB
real    0m22.797s
user    0m22.787s
sys     0m0.003s

Intel(R) Xeon(R) CPU E5345  @ 2.33GHz
cpu MHz         : 2327.502
cache size      : 4096 KB
real    0m34.086s
user    0m33.954s
sys     0m0.011s

Amazon EC2 Small Instance
1 EC2 Compute Unit (1 virtual core with 1 EC2 Compute Unit)
 
One EC2 Compute Unit provides the equivalent CPU capacity of a 1.0-1.2 GHz 2007 Opteron or 2007 Xeon processor. This is also the equivalent to an early-2006 1.7 GHz Xeon processor referenced in our original documentation.

Intel(R) Xeon(R) CPU           E5507  @ 2.27GHz
cpu MHz         : 2266.746
cache size      : 4096 KB

第一次：
real    1m42.415s
user    1m39.924s
sys     0m0.546s

第二次:
real    1m42.580s
user    1m40.164s
sys     0m0.471s

总的看来， EC2一个计算单元性能相当于i5-2300 CPU @ 2.80GHz一个core的1/4~1/5， 和官方给的说法差不多。

High-CPU Extra Large Instance
7 GB of memory, 20 EC2 Compute Units (8 virtual cores with 2.5 EC2 Compute Units each), 1690 GB of local instance storage, 64-bit platform
Heavy Utilization Reserved: 1 year Term要$2210, 3 year Term要$3400

Cluster Compute Quadruple Extra Large Instance
23 GB memory,33.5 EC2 Compute Units (2 x Intel Xeon X5570, quad-core “Nehalem” architecture)--平均4.2 Compute Unit = 1 Xeon X5570 core
On-Demand 价格 $1.30 per hour 一年要7000+$ 很贵.
Heavy Utilization Reserved: 1 year Term要$4060

Cluster Compute Eight Extra Large Instance
60.5 GB memory, 88 EC2 Compute Units (eight-core 2 x Intel Xeon)-- 平均5 Compute Unit = 1 Xeon core
$2.40 per hour 

用openssl来测试cpu运算能力

命令： openssl speed rsa1024

在Intel(R) Core(TM) i5-2300 CPU @ 2.80GHz的表现如下:  2902 signs/s
       sign     verify      sign/s verify/s
rsa 1024 bits 0.000345s 0.000020s   2902.3  50950.2

Amazon EC2 small instance with 1 compute unit and 1.7GMem: 302 signs/s

EC2 actively limits CPU to what is assigned to your instance class. Micro instances are the only ones with burstable CPU assignment.
 
Rackspace cloud doesn't limit CPU, but how much CPU you get will depend on how much CPU the instance sharing your host are using. You will probably see less consistent performance over time.

Using an ELB is the best way to offload SSL processing.