script, doc: capture trace

On Linux, the perf user-space tool can be used for capturing.  With a few
scripts, the captured trace can be processed with ptxed and ptdump.

Also the Simple-PT project on github provides support for capturing and
decoding Intel PT on Linux.

Add those scripts and document everything.

Change-Id: Icaa54feec009ca7b8f1d4e578c502240bd5d4a94
Signed-off-by: Markus Metzger <markus.t.metzger@intel.com>
3 files changed