Mechanisms for time based context sampling of trace data with support for multiple virtual machines are provided. In response to the occurrence of an event, a plurality of sampling threads associated with a plurality of executing threads executing on processors of a data processing system are awakened. For each sampling thread, an execution state of a corresponding executing thread is determined with regard to one or more virtual machines of interest. For each sampling thread, based on the execution state of the corresponding executing thread, a determination is made whether to retrieve trace information from a virtual machine of interest associated with the corresponding executing thread. For each sampling thread, in response to a determination that trace information is to be retrieved from a virtual machine of interest associated with the corresponding executing thread, the trace information is retrieved from the virtual machine.