[coreboot] [RFC] How to add “nested” time stamps?

[Paul Menzel]

Dear coreboot folks,

I’d like to add more time stamps for instrumentation/benchmarking.

I started with the timer initialization, and submitted two change sets
[1][2].

After rebuilding the utility `cbmem`, the relevant output looks like
below.

```
  60:device initialization                             457,880 (9,886)
 120:starting timer init                               472,001 (14,121)
 121:finished timer init                               472,008 (6)
  70:device setup done                                 472,751 (742)
```

Would that be acceptable to have nested entries? The down side is, the
time from *device initialization* to *device setup done* has to be
calculated manually now.

Also, I just chose the numbers 120 and 121 arbitrarily. Are there any
best practices for that to keep that extensible?

Thanks,

Paul

PS: If somebody has an idea on the weird build error on the DMP
Vortex86EX [3], I’d appreciate any help.

```
    ROMCC      romstage.inc
timestamp_serialized.h:23.16: 
bad type specifier :ident:
src/arch/x86/Makefile.inc:254: recipe for target '/dev/cb-build/coreboot-gerrit.0/DMP_EX/mainboard/dmp/vortex86ex/romstage.inc' failed
make[1]: *** [/dev/cb-build/coreboot-gerrit.0/DMP_EX/mainboard/dmp/vortex86ex/romstage.inc] Error 1
make[1]: Leaving directory '/home/coreboot/slave-root/workspace/coreboot-gerrit'
```

[1] https://review.coreboot.org/17701
[2] https://review.coreboot.org/17702
[3] https://qa.coreboot.org/job/coreboot-gerrit/47088/testReport/junit/%28root%2...