Kbase P91597: Windows Webspeed application responses slow under increased load when large amount of agents are add
| Autor |
Progress Software Corporation - Progress |
| Acesso |
Público |
| Publicação |
29/10/2008 |
|
Status: Verified
SYMPTOM(s):
Webspeed application responses slow under increased load
The more agents running, the slower the response
CPU utilisation never goes above 40%
Multiple CPU machine
Lots of context-switching when more agents are added
No apparent bottleneck on any resources, i.e., CPU, memory, disk and network
Problem not reproducible on UNIX platforms
FACT(s) (Environment):
OpenEdge 10.x
Windows NT 32 Intel/Windows 2000
CAUSE:
WebSpeed is a high performance, application server which runs web based applications. The actual work done is handled agents. Scalability is handled through the creation and use of multiple agents. Generally speaking, the more agents handling the workload, the greater the throughput is. This is true unless some barrier is encountered in the environment, whether it be a restriction in bandwidth or CPU.
In a highly tuned application run on a Windows system, after a certain number of processes have been started, throughput may be restricted by CPU capacity because of the high overhead incurred by Windows in starting and maintaining processes. Essentially, Windows has a high overhead for starting and maintaining processes. This overhead is much higher than encountered in Unix or Linux based operating systems. For a small number of processes this overhead has no effect, but for larger loads it becomes significant.
FIX:
For a Windows based WebSpeed application, optimal performance will come from using just enough agents and not starting more than is needed.