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I have an embedded system with code that I'd like to benchmark. In this case, there's a single line I want to know the time spent on (it's the creation of a new object that kicks off the rest of our application).

I'm able to open Trace->Chart->Symbols and see the time taken for the region selected with my cursor, but this is cumbersome and not as accurate as I'd like. I've also found Perf->Function Runtime, but I'm benchmarking the assignment of a new object, not of any particular function call (new is called in multiple places, not just the line of interest).

Is there a way to view the real-world time taken on a line of code with Trace32? Going further than a single line: would there be a way to easily benchmark the time between two breakpoints?

codehearts
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2 Answers2

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The solution by codehearts, which uses the RunTime commands, is just fine if you don't have a real-time trace. It works with any Lauterbach tool and any target CPU.

However if you have a real-time trace (e.g. CPU with ETM and Lauterbach PowerTrace hardare), I recommend to use the command Trace.STATistic.AddressDURation <start-addr> <end-addr> instead. This command opens a window which shows the average time between two addresses. You get best results, if you execute the code between the two addresses several times.

If you are using an ARM Cortex CPU, which supports cycle-accurate timing information (usually all Cortex-A, Cortex-R and Cortex-M7) you can improve the accuracy of the result dramatically by using the setting ETM.TImeMode.CycleAccurate (together with ETM.CLOCK <core-frequency>).

If you are using a Lauterbach CombiProbe or uTrace (and you can't use the ETM.TImeMode.CycleAccurate) I recommend the setting Trace.PortFilter.ON. (By default the port-filter is set to PACK, which allows to record more data and program flow, but with a slightly worse timing accuracy.)

Holger
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Opening the Misc->Runtime window shows you the total time taken since "laststart." By setting a breakpoint on the first line of your code block and another after the last line, you can see the time taken from the first breakpoint to the second under the "actual" column.

codehearts
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    The RunTime command of TRACE32 measures only the time between starting the CPU and detecting a stopped CPU. However there might be a big delay between an actually stopping CPU and the debugger detecting the halt via JTAG polling. You can view the possible measurement error with command `PRINT RunTime.ACCURACY()` (or by hovering with the mouse cursor over the "laststart" value). – Holger May 29 '17 at 14:28
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    You can improve accuracy with command `SYStem.POLLING.CONTinuous` – Holger May 29 '17 at 14:36