scripts: dts: optimize gen_driver_kconfig_dts.py execution time

[gudnimg]

Replace yaml.compose() with a faster event-stream parser that extracts the first top-level compatible scalar without constructing the full YAML node tree.

This reduces per-file parsing overhead when iterating over thousands of binding files. Binding files are now opened in binary mode and passed directly to SafeLoader/CSafeLoader.

Benchmark (Windows, Python 3.12.3, 2913 bindings):

• before: 874ms, 641862 function calls
• after: 603ms, 188557 function calls

Benchmark (Ubuntu 24.04, Python 3.12, 3388 bindings).

• latest Zephyr main as of writing which is 5a58989:
• before: 466ms, 746041 function calls
• after: 170ms, 118802 function calls

So on my end I'm seeing the following improvements:

• Windows: ~30% improvement
• Linux: ~60% improvement

On Windows half the time, 300ms, is spent on opening 2913 binding files. While on Ubuntu it is only 32ms for 3388 files. Which explains a larger difference between the OS performance.

Testing Method

def main()
    import cProfile, pstats, io
    from pstats import SortKey
    pr = cProfile.Profile()
    pr.enable()
    
    # code under test is placed here

    pr.disable()
    s = io.StringIO()
    sortby = SortKey.CUMULATIVE
    ps = pstats.Stats(pr, stream=s).sort_stats(sortby)
    ps.print_stats()
    print(s.getvalue())

[sonarqubecloud]

Quality Gate passed

Issues
1 New issue
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[JarmouniA]

Does it work with child-bindings?
ex.

zephyr/dts/bindings/i2c/ti,tca9544a.yaml

Line 10 in 5a58989

compatible: "ti,tca9544a-channel"

[gudnimg]

Does it work with child-bindings? ex.

zephyr/dts/bindings/i2c/ti,tca9544a.yaml

Line 10 in 5a58989

compatible: "ti,tca9544a-channel"

@JarmouniA My initial thought is no, its just ignored as the value is not at root-level. The contents of the output file Kconfig.dts is the same as before so I wouldn't expect any change in behavior. I'll double check this again 👍

---

Unrelated, I just discovered why Windows is so slow on my end. Turns out one of my disk drives has a lot more file filters:

C: drive:

fltmc instances -v C:

Instances for C: volume:

Filter                  Altitude        Instance Name       Frame   SprtFtrs  VlStatus
--------------------  ------------  ----------------------  -----   --------  --------
bindflt                  409800     bindflt Instance          0     0000000f
UCPD                     385250.5   UCPD - Top Instance       0     0000000f
WdFilter                 328010     WdFilter Instance         0     0000000f
storqosflt               244000     storqosflt                0     0000000f
wcifs                    189900     wcifs Instance            0     0000000f
gameflt                  189850     gameflt Instance          0     0000000b
CldFlt                   180451     CldFlt                    0     0000000f
bfs                      150000     bfs                       0     0000000f
FileCrypt                141100     FileCrypt Instance        0     0000000f
luafv                    135000     luafv                     0     0000000f
Wof                       40700     Wof Instance              0     0000000f
FileInfo                  40500     FileInfo                  0     0000000f

While on my D drive:

fltmc instances -v D:

Instances for D: volume:

Filter                  Altitude        Instance Name       Frame   SprtFtrs  VlStatus
--------------------  ------------  ----------------------  -----   --------  --------
UCPD                     385250.5   UCPD - Top Instance       0     0000000f
WdFilter                 328010     WdFilter Instance         0     0000000f
gameflt                  189850     gameflt Instance          0     0000000b
bfs                      150000     bfs                       0     0000000f
Wof                       40700     Wof Instance              0     0000000f
FileInfo                  40500     FileInfo                  0     0000000f

I see almost 2x better performance in opening/closing files! 300ms reduced to 138ms. Very interesting... will look into this further :)

[JarmouniA]

The contents of the output file Kconfig.dts is the same

Huh, so we were ignoring child-bindings all this time, interesting! I hope there is no usage of a DT_HAS_{CHILD-COMPAT}_ENABLED Kconfig symbol in-tree.