| AMD Confidential |
User Manual | November 21st, 2008 |
7.22 XTR Device
XTR is a trace record and playback mechanism that is instrumental for applications that are not dependent on the specific version of the CPU. An XTR trace contains the interaction of the processor with the rest of the system in an XML based log file. The XTR trace file can be played back and could be used to simulate behavior of one or more devices within a system, which in turn may be used to analyze the CPU's performance or to perform conformance analysis between various revs and models of the CPU. XTR may also be used in studies where the behavior of some devices needed but the use of an actual device or its software model is either difficult of impossible due to various constraints.
XTR has two files, a binary file which has the memory dump of the system and an XML based text file which contains the log of the events or messages that go in and out a non- coherent port of the Northbridge, including the DMA signals from devices on the (host‟s) secondary bus to the DIMM. XTR playback mechanism essentially replaces all the devices including the Northbridge and downwards and feeds the processor with the data present in the XTR XML file. The structure of both binary file and XML file is discussed below.
XTR can be used both in
There are two modes of XTR, XTR Record and XTR Playback. The simulator supports both modes and one mode does not necessitate the other. The simulator could be used to record XTR traces only or playback XTR traces generated from other sources as far as the XTR specification is followed correctly (see Section 7.22.4, “Limitations”, on page 117).
An XTR XML file contains Initialization Data, Events and Instructions. XTR Initialization data stores the state of CPU just before XTR recording is initiated. This data is used to initialize the CPU and memory parameters during Playback (the memory itself is initialized from the contents of the binary file). Any register that does not have corresponding initialization data in XTR XML file will be initialized with zero. XTR events fall into two categories:
∙Dormant Events, which record an event occurrence but do not trigger an event during playback.
∙Active events that are recorded in XTR file and are actively triggered during playback.
IOR, IOW, MEMR, MEMW, RDMSR are examples of dormant events and INTR, APIC, DMAW, EOT are examples of Active events. XTR Instructions are commands that are injected in the XTR trace to give special instructions during XTR playback. FJMP (Force Jump) is an XTR Instruction.
110 | Chapter 7: Device Configuration |
