Files
ollama/x/imagegen/mlx
Daniel Hiltgen 8968740836 mlx: Improve M5 performance with NAX (#15345)
* mlx: Improve M5 performance with NAX

This modifies the Mac release to now have 2 builds of MLX for broader
compatibility while supporting the latest M5 hardware features.  NAX requires
building with xcode 26.2 and targetting support only for OS v26 and up.  Since
we want to support older MacOS versions as well, we now need 2 different MLX
builds and runtime detection logic to select the optimal version.  The newer
build will detect NAX missing at runtime, so it is safe to run on pre M5 macs.

* mac: prevent generate on cross-compiles

For some versions of Xcode, cmake builds are failing due to header problems in
cross-compiling during the generate phase.  Since generate is producing arch
independent generated output, we can skip this during cross-compiling.
2026-04-07 08:12:24 -07:00
..
2026-03-23 11:28:44 -07:00
2026-03-23 11:28:44 -07:00
2026-03-23 11:28:44 -07:00

MLX Memory Management

| This package will get consolidated with x/ml/backend/mlx in the future.

Automatic Tracking

All arrays are automatically tracked when created. On Eval(), non-kept arrays are freed.

API

result := mlx.Matmul(x, w) // arrays automatically tracked
mlx.Eval(result)           // free non-kept, eval result (auto-kept)

Key Functions

  • mlx.Eval(outputs...) - free non-kept arrays, then evaluate (outputs auto-kept)
  • mlx.AsyncEval(outputs...) - async version of Eval (outputs auto-kept)
  • mlx.Keep(arrays...) - mark arrays to survive cleanup (for weights, caches)
  • array.Free() - mark array for cleanup on next Eval

Loop Pattern

for step := 0; step < maxTokens; step++ {
    logits := model.Forward(token, caches)
    oldToken := token
    token = sample(logits)

    // Keep cache state across iterations
    for _, c := range caches {
        mlx.Keep(c.State()...)
    }

    oldToken.Free()       // mark for cleanup
    mlx.AsyncEval(token)  // frees old, evals new
}

Notes

  • Eval() and AsyncEval() auto-keep their outputs
  • Free() marks for cleanup - actual free happens during next Eval
  • Use Keep() for weights and cache state that must survive multiple Eval cycles
  • Arrays created inside compiled closures are managed by MLX, not tracked