[HELP] What is the pre-condition to run gprof?

### Description

I am trying to get LVGL profile with `gprof`.
I followed the nuttx `gprof` document, here is the configuration.

```
CONFIG_PROFILE_MINI=y
CONFIG_PROFILE_ALL=y
CONFIG_SYSTEM_GPROF=y
CONFIG_SYSTEM_GPROF_PRIORITY=100
CONFIG_SYSTEM_GPROF_STACKSIZE=4096
CONFIG_FRAME_POINTER=y
```
The LVGL is built with GNU Compiler with `-pg` added.
The steps for profiling LVGL are:
```
nsh> mount -t tmpfs /tmp
nsh> gprof start
nsh> lvgldemo "benchmark" &
nsh> gprof stop
nsh> gprof dump /tmp/gmon.out
nsh> ls -l /tmp/
/tmp:
-rwxrwxrwx 1121704 gmon.out
nsh> hexdump /tmp/gmon.out
/tmp/gmon.out at 00000000:
0000: d0 01 10 80 e0 3c 32 80 a8 1d 11 00 79 18 05 00 .....<2.....y...
0010: e8 03 00 00 02 00 00 00 fe ff ff ff 50 a4 81 80 ............P...
0020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0030: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0040: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0050: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0060: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0070: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0090: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0110: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0120: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0130: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0140: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0150: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0160: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0170: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0190: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
01a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
01b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
01c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
01d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
01e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
01f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
/tmp/gmon.out at 00000200:
0000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0030: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0040: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0050: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0060: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0070: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0090: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0110: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0120: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0130: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0140: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0150: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0160: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0170: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0190: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
01a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
01b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
01c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
01d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
01e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
01f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
....
```
What I got is all-zeros!
So what is the precondition to run gprof correctly?

### Verification

- [x] I have verified before submitting the report.

Start with the NuttX gprof documentation and the listed profiling configuration, then reproduce the nsh sequence using tmpfs, gprof start/stop/dump, and the LVGL benchmark. Compare the resulting gmon.out with the expected profile format; done means identifying the required preconditions or documenting the remaining failure with a reproducible nonzero profile.

Written by the indexing model from the issue text.