Tuning for HTTP 1.1-Style Workload

In general, it is a trade-off between throughput and latency while tuning server-persistent connection handling. The keep-alive poll interval and timeout control latency. Lowering the value of these settings is intended to lower latency on lightly loaded systems (for example, reduce page load times). Increasing the values of these settings is intended to raise aggregate throughput on heavily loaded systems (for example, increase the number of requests per second the server can handle). However, if there's too much latency and too few clients, aggregate throughput suffers as the server sits idle unnecessarily. As a result, the general keep-alive subsystem tuning rules at a particular load are as follows:

• If there's idle CPU time, decrease the poll interval.

• If there's no idle CPU time, increase the poll interval.

Also, chunked encoding could affect the performance for HTTP 1.1 workload. Tuning the response buffer size could positively affect the performance. A higher response buffer size in the configuration's Performance tab ⇒ HTTP tab would result in sending a Content-length: header, instead of chunking the response. To set the buffer size using the CLI, use the wadm set-http-prop command's output-buffer-size property.

You can also set the buffer size for a Service-class function in the obj.conf file, using the UseOutputStreamSize parameter. UseOutputStreamSize overrides the value set using the output-buffer-size property. If UseOutputStreamSize is not set, Web Server uses the output-buffer-size setting. If the output-buffer-size is not set, Web Server uses the output-buffer-size default value of 8192.

The following example shows using the CLI to increase the output buffer size, then deploying the configuration (used if UseOutputStreamSize is not specified in obj.conf):

./wadm set-http-prop --user=admin-user --password-file=admin-password-file 
--config=config-name output-buffer-size=16384
./wadm deploy-config --user=admin-user --password-file=admin-password-file
 --config=config-name

The following example shows setting the buffer size for the nsapi_test Service function:

<Object name="nsapitest">
 ObjectType fn="force-type" type="magnus-internal/nsapitest"
 Service method=(GET) type="magnus-internal/nsapitest" fn="nsapi_test"
 UseOutputStreamSize=12288
</Object>