Address review: add architecture-specific threshold selection
The push threshold map was labeled as sm100-specific but applied
unconditionally to all architectures. Now:
- PUSH_THRESHOLD_SM100 is only used on Blackwell (compute capability 10.x)
- PUSH_THRESHOLD_DEFAULT provides conservative 512 KB thresholds for
architectures without tuned values
- _THRESHOLD_BY_ARCH maps GPU major compute capability to threshold tables
- A log message is emitted when falling back to conservative defaults
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Committer
Alexander Matveev