We add Grizzly Nio engine to one of existing server, which used to be one
thread per connection classic model. During load test we noticed that NIO
server consumes twice CPU power than the classic model when serving the same
amount of connections.
Here's our configurations:
Here are some statistics:
Hardware: Dells 2950 with 16 GB RAM, total 8 processors, Intel(R) Xeon(R)
CPU E5345 @ 2.33GHz, Linux kernel 2.6
Software: JDK v1.5.6
There are 4 instance of the server application configured on one box
Grizzly Configs:
100 max worker threads (8K buffer size)
150 max output buffer pool size (4K buffer size)
use_direct_buffer = true
selector timeout = 500
Keep alive is true (persistent connections)
Tested with : 7200 client connections
Total CPU usage for all 4 instances are 44.59% (with NIO engine)
CPU usage is 24.76% (without Nio engine)
So far as memory, NIO server uses slightly less memory in this case.
The memory consumption could be linear because we keep lots of state
information for each connection (user). Other than that, what other
parameters should I pay attention to in order to scale the server to serve
10,000 or more connections without burning up CPU?
The old server can serve 12000 connections with 4 instance at <= 50% CPU
usage.
Would it be better to run 2 instances of NIO server instead of 4?
Your opinion and suggestion is greatly appreciated.
thanks,
Fay