[AUTO_SCHEDULER] Add feature extraction directly from PrimFunc (#10455)

* [AUTO_SCHEDULER] Add feature extraction directly from PrimFunc

Allow users to directly extract features from a PrimFunc. Extracted
features can be used to get an estimate of flops, memory load size, or
arithmetic intensity from a PrimFunc.

Also fix feature extraction to correctly measure the number of
arithmetic operations width vector datatypes.

* fix param name

* log scale in cc instead of python

* rename functions, remove load/store

* forgot rename in tests

* forgot to commit rename

Author: Tristan Konolige

include/tvm/auto_scheduler/feature.h

@@ -33,6 +33,7 @@
 
 #include <tvm/auto_scheduler/compute_dag.h>
 #include <tvm/auto_scheduler/measure.h>
+#include <tvm/tir/function.h>
 
 #include <string>
 #include <vector>
@@ -41,14 +42,15 @@ namespace tvm {
 namespace auto_scheduler {
 
 /*!
- * \brief Get per-store feature from a TIR Stmt
- * \param stmt The input lowered TIR statement
+ * \brief Get per-store features from a TIR PrimFunc
+ * \param func The input lowered TIR PrimFunc
  * \param cache_line_size The size of cache line in bytes
  * \param max_n_bufs The maximum number of extracted buffers for one statement
  * \param ret The returned feature vector
+ * \param log_scale Should the outputs be scaled by log2(1+x).
  */
-void GetPerStoreFeature(const Stmt& stmt, int cache_line_size, int max_n_bufs,
-                        std::vector<float>* ret);
+void GetPerStoreFeature(const PrimFunc& func, int cache_line_size, int max_n_bufs,
+                        std::vector<float>* ret, bool log_scale = true);
 
 /*
  * \brief Get the names of elements in the feature vector. Use this for debug and inspection.

python/tvm/auto_scheduler/feature.py

@@ -26,14 +26,15 @@
 The feature specification is defined by `src/auto_scheduler/feature.cc::FeatureSet`
 """
 
-from typing import List, Tuple, Union, Optional
+from typing import List, Tuple, Union, Optional, Dict
 import struct
 
 import numpy as np
 
 from .loop_state import State, StateObject
 from .measure import MeasureInput, MeasureResult
 from . import _ffi_api
+from ..tir import PrimFunc
 
 # The maximum number of extracted buffers for one statement
 DEFAULT_MAX_N_BUFS = 5
@@ -252,3 +253,78 @@ def get_per_store_feature_names(max_n_bufs: Optional[int] = None) -> List[str]:
         The names of elements in the flatten feature vector
     """
     return _ffi_api.GetPerStoreFeatureNames(max_n_bufs or DEFAULT_MAX_N_BUFS)
+
+
+def features_from_primfunc(
+    func: PrimFunc,
+    cache_line_bytes: int = 64,
+    max_n_bufs: Optional[int] = None,
+    log_scale: bool = False,
+) -> np.ndarray:
+    """Extract performance features from a PrimFunc.
+
+    Parameters
+    ----------
+    func: PrimFunc
+        PrimFunc from which features will be extracted. Each store operation to
+        a unique buffer in the function will result in one row of features in
+        the output.
+
+    cache_line_bytes: int, optional
+        Size of a cache line in bytes. Defaults to 64 which is the size for
+        most x86 processors.
+
+    max_n_bufs: int, optional
+        Maximum number of buffers in generated features. This determines the
+        length of the resulting feature vector.
+
+    log_scale: bool
+        Should entries in the feature vector be scaled by log2(x + 1). Defaults
+        to False. Use True if using features with a cost model.
+
+    Returns
+    -------
+    np.ndarray
+        Output features, one row per store into a unique buffer statement in `func`.
+    """
+    return _ffi_api.FeaturesFromPrimFunc(
+        func, cache_line_bytes, max_n_bufs or DEFAULT_MAX_N_BUFS, log_scale
+    ).numpy()
+
+
+def named_features_from_primfunc(
+    func: PrimFunc,
+    cache_line_bytes: int = 64,
+    max_n_bufs: Optional[int] = None,
+    log_scale: bool = False,
+) -> Dict[str, np.ndarray]:
+    """Extract performance features and associated names from a PrimFunc.
+
+    Parameters
+    ----------
+    func: PrimFunc
+        PrimFunc from which features will be extracted. Each store operation to
+        a unique buffer in the function will result in one row of features in
+        the output.
+
+    cache_line_bytes: int, optional
+        Size of a cache line in bytes. Defaults to 64 which is the size for
+        most x86 processors.
+
+    max_n_bufs: int, optional
+        Maximum number of buffers in generated features. This determines the
+        length of the resulting feature vector.
+
+    log_scale: bool
+        Should entries in the feature vector be scaled by log2(x + 1). Defaults
+        to False. Use True if using features with a cost model.
+
+    Returns
+    -------
+    Dict[str, np.ndarray]
+        Mapping from feature name to features. One element per store into a
+        unique buffer statement in `func`.
+    """
+    features = features_from_primfunc(func, cache_line_bytes, max_n_bufs, log_scale)
+    names = get_per_store_feature_names(max_n_bufs)
+    return {name: features[:, i] for i, name in enumerate(names)}