App compilation timing

[dido18]

Motivation

Test the decrease of the compilation using the arduino-cli arduino/arduino-cli#2961 (comment)

Calculate the timing of the three steps

1. arduino-cli init : ~1.5 seconds
2. arduino-cli compile (see difference below)
3. arduino-cli upload (ram) 6-7 seconds

The compile timings are the following, based on different scenarios

Scenario	arduino-cli 1.4.1	arduino-cli PR #2961	arduino-cli PR #3105
First compile	~1m40s	~1m40s	~1m40s
Compile (sketch changed)	~30–40s	~30–40s	~30-40s
Compile (sketch unchanged)	~30–40s	~6–7s	~1s

Change description

• sketch used for the test sketch.zip

Additional Notes

Reviewer checklist

• PR addresses a single concern.
• PR title and description are properly filled.
• Changes will be merged in main.
• Changes are covered by tests.
• Logging is meaningful in case of troubleshooting.

[dido18]

This is the companion issue to check the time to compile a sketch into the board arduino/arduino-cli#2961 (comment)

• command arduino-app-cli app start user:scratch-arduino-app --log-level=info

On board

With arduino-cli 1.4.1

1st run

-  INFO arduino-cli init completed duration=1.249965538s
-  INFO arduino-cli compile completed duration=1m39.797685934s
-  INFO arduino-cli upload (ram) completed duration=6.920289734s

2nd run

-  INFO arduino-cli init completed duration=1.27567175s
-  INFO arduino-cli compile completed duration=34.020548559s
-  INFO arduino-cli upload (ram) completed duration=6.843204067s

3rd run

INFO arduino-cli init completed duration=1.278461544s
INFO arduino-cli compile completed duration=33.523823675s
INFO arduino-cli upload (ram) completed duration=6.83991578s

with arduino-cli 0.4.2 XXX

rm -rf .cache/ && arduino-app-cli app start user:scratch-arduino-app --log-level info

1st run

2026/02/13 10:57:19 INFO arduino-cli init completed duration=1.223487315s
2026/02/13 10:59:01 INFO arduino-cli compile completed duration=1m41.83323615s
2026/02/13 10:59:08 INFO arduino-cli upload (ram) completed duration=6.821932623s

2nd run

2026/02/13 11:01:58 INFO arduino-cli init completed duration=1.274086375s
2026/02/13 11:02:15 INFO arduino-cli compile completed duration=17.301468765s
2026/02/13 11:02:22 INFO arduino-cli upload (ram) completed duration=6.840720267s

3rd

2026/02/13 11:05:01 INFO arduino-cli init completed duration=1.243830519s
2026/02/13 11:05:07 INFO arduino-cli compile completed duration=6.020854974s
2026/02/13 11:05:14 INFO arduino-cli upload (ram) completed duration=6.829373269s

4th

2026/02/13 11:06:31 INFO arduino-cli init completed duration=1.227051477s
2026/02/13 11:06:37 INFO arduino-cli compile completed duration=6.043601243s
2026/02/13 11:06:44 INFO arduino-cli upload (ram) completed duration=6.824612425s

using Applab with 0.4.2-xxxx

1st compilation: 1m40

Feb 13 11:28:58 didoi arduino-app-cli[6833]: 2026/02/13 11:28:58 INFO arduino-cli init completed duration=1.310814348s
Feb 13 11:30:40 didoi arduino-app-cli[6833]: 2026/02/13 11:30:40 INFO arduino-cli compile completed duration=1m42.386061684s
Feb 13 11:30:47 didoi arduino-app-cli[6833]: 2026/02/13 11:30:47 INFO arduino-cli upload (ram) completed duration=6.848861146s

A file is edited: 30s

Feb 13 11:20:00 didoi arduino-app-cli[6833]: 2026/02/13 11:20:00 INFO arduino-cli init completed duration=1.29211581s
Feb 13 11:20:34 didoi arduino-app-cli[6833]: 2026/02/13 11:20:34 INFO arduino-cli compile completed duration=34.292129436s
Feb 13 11:20:41 didoi arduino-app-cli[6833]: 2026/02/13 11:20:41 INFO arduino-cli upload (ram) completed duration=6.885485761

NO sketch edit: 6-7seconds

Feb 13 11:25:22 didoi arduino-app-cli[6833]: 2026/02/13 11:25:22 INFO arduino-cli init completed duration=1.30363116s
Feb 13 11:25:28 didoi arduino-app-cli[6833]: 2026/02/13 11:25:28 INFO arduino-cli compile completed duration=6.278227968s
Feb 13 11:25:35 didoi arduino-app-cli[6833]: 2026/02/13 11:25:35 INFO arduino-cli upload (ram) completed duration=6.852994717

[Xayton]

@dido18 it would be nice to also compare the "compile an unchanged sketch" vs "compile a changed sketch".
Those are two different, but both interesting cases:

• in one case you are working on the sketch code, and that is the time you wait to recompile and upload each change
• in the other case your sketch does not change, are you are probably working on the Python code

[dido18]

@dido18 it would be nice to also compare the "compile an unchanged sketch" vs "compile a changed sketch". Those are two different, but both interesting cases:

• in one case you are working on the sketch code, and that is the time you wait to recompile and upload each change
• in the other case your sketch does not change, are you are probably working on the Python code

With 1.4.1

The "compile unchanged sketch" and "compile a changed sketch" take around ~30-40 seconds

With 1.4.2.xxx

• "compile a changed sketch": 30-40 seconds
• "compile unchanged sketch": around 7seconds

I will update the PR with a table summarising with the timing

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