Address Trace Collection Technique
Technique for Obtaining Traces- We have a number of Tektronix TLA720 logic analyzers gathering data from
the pins of Intel Pentium, Pentium II, and Xeon processors. The software we
want to trace runs on the processor, under any of several different operating
systems. When the buffer
on the data analyzer is full, it sends a signal over to the Pentium's
parallel port, triggering an interrupt. A special driver written for it
sends it into a tight loop until the data analyzer is ready for more
data. Meanwhile, the data analyzer sends the contents of its buffer over the
network to a workstation that saves it into our tape array drive. A program on
the workstation then goes through the raw data, saving out only the desired
bits in a specific format, and then compresses it back to disk. This program
then signals the data analyzer that it is ready for more data, causing the
data analyzer to unlock the processor.
Currently, we are taking address traces from the chip, meaning that
we record memory requests that the chip generates. This is useful for
research involving caches. Here is the
trace format.
We are collecting traces from various operating systems, including Windows NT,
Linux, and Windows 95. Device drivers which halt the machines as described
above are available:
- Linux, available for kernel
2.2.x.
- Windows NT. not currently available online.
- Windows 95, not currently available online.
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