Pdelta is a multithreaded daemon with rate limiting. You can specify the amount of bandwidth you would like it to use as well as the concurrency of importing processes. In this way, you can control how much of the Network and how much CPU it uses. Other than this, it tries to naturally overlap computation and network transfer. pdelta runs continuously with a fixed periodicity, which determines how often data is synchronized from the nodes. Currently, the period is about 2 hours. At the end of every period, it performs certain accounting actions such as tracking how many nodes it was able to contact, how much data was transferred, etc. This information goes into the accounting interface available at planetflow.planet-lab.org.
The set of IP addresses from which to fetch data are retrieved from PLC. At first, these addresses are fed into a local file called 'green', which defines the default level of priority. Sometimes, you may wish to treat a certain node in priority - for example when a complaint is received in its context. In such acses, you can add the IP address of the node to one of two files in the same directory, 'blue' and 'red', both of which define additional (higher) levels of priority. pdelta will suck in these files before refreshing its list from pLC, or going back to 'green'.