Autodetect tiny mode in AS #27893

[eivanov89]

Changelog entry

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Changelog category

• Not for changelog (changelog entry is not required)

Description for reviewers

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[Copilot]

Pull Request Overview

This PR enhances the scheduler configuration logic to automatically detect and enable "tiny mode" based on CPU count. Previously, tiny mode was only enabled through explicit configuration; now it will automatically activate for systems with 4 or fewer CPU cores.

Key Changes:

• Introduced CPU count-based auto-detection for tiny mode (≤4 cores)
• Extracted magic numbers into named constants for better maintainability

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[github-actions]

⚪ 2025-11-06 12:32:26 UTC Pre-commit check linux-x86_64-release-asan for 9d07c25 has started.
⚪ 2025-11-06 12:32:30 UTC Artifacts will be uploaded here
⚪ 2025-11-06 12:33:54 UTC ya make is running...
🟡 2025-11-06 14:41:10 UTC Some tests failed, follow the links below. This fail is not in blocking policy yet

Ya make output | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
17479	17014	0	218	220	27

🟢 2025-11-06 14:41:24 UTC Build successful.
🟢 2025-11-06 14:41:51 UTC ydbd size 3.8 GiB changed* by +1.6 KiB, which is < 100.0 KiB vs main: OK

ydbd size dash	main: fe60a68	merge: 9d07c25	diff	diff %
ydbd size	4 071 193 640 Bytes	4 071 195 304 Bytes	+1.6 KiB	+0.000%
ydbd stripped size	1 511 147 368 Bytes	1 511 147 880 Bytes	+512 Bytes	+0.000%

^{*please be aware that the difference is based on comparing your commit and the last completed build from the post-commit, check comparation}

[github-actions]

🟢 2025-11-06 12:32:50 UTC The validation of the Pull Request description is successful.

[github-actions]

⚪ 2025-11-06 12:34:53 UTC Pre-commit check linux-x86_64-relwithdebinfo for 9d07c25 has started.
⚪ 2025-11-06 12:34:59 UTC Artifacts will be uploaded here
⚪ 2025-11-06 12:37:21 UTC ya make is running...
🟡 2025-11-06 14:10:47 UTC Some tests failed, follow the links below. Going to retry failed tests...

Ya make output | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
33901	32487	0	4	1385	25

⚪ 2025-11-06 14:11:13 UTC ya make is running... (failed tests rerun, try 2)
🟢 2025-11-06 14:20:55 UTC Tests successful.

Ya make output | Test bloat | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
53 (only retried tests)	38	0	0	0	15

🟢 2025-11-06 14:21:06 UTC Build successful.
🟢 2025-11-06 14:21:27 UTC ydbd size 2.3 GiB changed* by +1.3 KiB, which is < 100.0 KiB vs main: OK

ydbd size dash	main: fe60a68	merge: 9d07c25	diff	diff %
ydbd size	2 430 800 280 Bytes	2 430 801 648 Bytes	+1.3 KiB	+0.000%
ydbd stripped size	516 352 072 Bytes	516 352 456 Bytes	+384 Bytes	+0.000%

^{*please be aware that the difference is based on comparing your commit and the last completed build from the post-commit, check comparation}