For debugging UEFI, print statements (“printf”) are often an engineer’s most powerful tool: some bugs are caused by complex sequences of events that are too long and intricate to root-cause using just breakpoints and watch windows. But printf has some drawbacks: its processing code can run hundreds of instructions in the target code being debugged, and this execution time added to the backpressure caused by transports such as serial console output can cause the performance of the boot code to slow significantly. This can mask timing-dependent bugs that are often the most intermittent or seemingly random. An at-speed version of print statements, enabled by the Intel Trace Hub, provides all the benefits of printf without the performance impact.
This webinar will provide advanced examples on the use of at-speed printf in conjunction with other debugging and trace tools to triage intermittent bugs on Intel platforms.