Port Throttling

2011-10-25T20:42:33Z

195.146.245.223: /* Current Throttled Ports */

Sometimes the frame rate from Output Ports has to be rate limited. The ''ThrottledOutputPortDecorator'' allows rate limits to be configured on OutputPorts using a [http://en.wikipedia.org/wiki/Token_bucket Token Bucket Algorithm].

The following example shows applying the ''ThrottledOutputPortDecorator'' to an Output port to rate limit the output.

Before (no throttling):
<pre>
OutputPort *output_port = new UsbProOutputPort(this, 0, "");
</pre>

After (throttle to 190 frames per second)

<pre>
OutputPort *output_port = new ThrottledOutputPortDecorator(
new UsbProOutputPort(this, 0, ""), // the port to throttle
plugin_adaptor->WakeUpTime(), // the select server wake up time
10, // start with 10 tokens in the bucket
190); // throttle to 190 frames per second
</pre>

When port throttling is in place, messages will appear at log level 4 similar to:

<pre>
PortDecorators.h:48: Port rated limited, dropping frame
</pre>

=== Current Throttled Ports ===

* [[DMX USB Pro]] - 190 frames/second
* [[Arduino RGB Mixer]] - 20 frames/second
* [[DMX-TRI]] - 40 frames/second

For some devices, values can be changed in ~/.ola/ola-usbserial.conf

wiki.openlighting.org - User contributions [en]

Port Throttling